In The Sky This Month – January 2011

This feature highlights a number of meteor showers, comets and asteroids which are visible during the month of January 2011.

January 2011 Highlights
* Quadrantids Meteor Shower peaks on Jan 4
* Jupiter rules the evening sky, while...
* Venus dominates the morning sky with ...
* Mercury also in the midst of a good morning apparition

Note: If anyone has pictures or observations of these objects/events and want to share them with my readers, send them to the Transient Sky at <transientsky1@yahoo.com>.

Planets

Moon - The table below lists important lunar dates for the month, including the phases of the Moon and nights of lunar-planetary and lunar-stellar conjunctions.

Jan 1 - Moon 3° from bright star Antares
Jan 2 - Moon 4° from Mercury
Jan 4 - New Moon
Jan 10 - Moon 6° from Jupiter and Uranus
Jan 12 - First Quarter Moon
Jan 15 - Moon 1.3° from Pleiades
Jan 16 - Moon 8° from bright star Aldebaran
Jan 19 - Full Moon 9° from bright star Pollux
Jan 20 - Moon 4° from Beehive Cluster
Jan 21 - Moon 5° from bright star Regulus
Jan 25 - Moon 8° from Saturn and 3° from bright star Spica
Jan 26 - Third Quarter Moon
Jan 29 - Moon 3° from bright star Antares
Jan 30 - Moon 4° from Venus

Jupiter (and Uranus, too…) - The ‘King of the Planets’ continues his reign as the uncontested ‘King of the Evening Sky’ though fading from magnitude -2.3 to -2.2, nothing but the Moon rivals it in brightness. Located on the Pisces/Aquarius border, Jupiter is easy to find in the south as it gets dark. Jupiter then spends the rest of the evening getting lower in the southwest sky.

If you have a pair of binoculars or small telescope take a look at Jupiter. See if you can see any of its 4 bright Galilean moons or its large atmospheric belts (there are usually 2 prominent belts but 1 has recently disappeared though it may make a comeback at any time). In addition, Jupiter is close to Uranus all month long. On Jan 4 the two are 0.5° apart.

Jan 4 - Jupiter and Uranus within 0.5° of each other
Jan 10 - Moon within 6-7° of Jupiter and Uranus

Saturn – Saturn rises during the middle of the night. Located in Virgo, the ringed planet is a close match in brightness (mag +0.7) to Spica, the brightest star in Virgo (mag +1.0). Saturn spends the entire month within 8-9° of Spica.

Jan 25 - Moon within 8° of Saturn

Venus – After passing through inferior conjunction in late October , Venus is now the dominant sight in the morning sky. On Dec 1, Venus rises almost 3 hours before the Sun in the eastern sky. Unlike this year’s evening apparition which was poorly placed, Venus’ current stay in the morning sky will be a good one for northern observers. Through a telescope it currently looks like a brilliant ‘half moon’.

Jan 8 - Venus at Greatest Elongation West
Jan 17 - Venus within 8° of bright star Antares
Jan 30 - Moon within 3.5° of Venus

Mercury – Mercury is in the middle of a good morning apparition all month long.

Jan 2 - Moon within 4° of Mercury
Jan 9 - Greatest Elongation West

Mars – Too close to the Sun for observation.

Meteors

Meteor activity starts to plummet in January. The year is usually split in 2 with January through June having low rates with few major showers while July through December (really through the 1st week of January) have high rates with many major showers.

Sporadic Meteors

Sporadic meteors are not part of any known meteor shower. They represent the background flux of meteors. Except for the few days per year when a major shower is active, most meteors that are observed are Sporadics. This is especially true for meteors observed during the evening. During September, 10-16 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

Quadrantids (QUA) [Max Date = Jan 4, Max Rate = ~60-150 per hour under dark skies]

The Quadrantids are the best shower that you’ve probably never heard of. It’s bad enough that this shower peaks in the middle of winter in the northern hemisphere, but it is also named after a long defunct constellation. When first identified in the early 1800s, the meteors were observed to radiate from the small faint constellation of Quadrans Muralis (the Mural Quadrant). Unfortunately, the constellation didn’t make the cut when the official list of 80 constellations was set in 1930. Today, Quadrans Muralis and the radiant of the Quadrantids can be found on the northern reaches of the constellation Bootes.

Another strike against observing the Quadrantids is their short duration. Most showers, like the Perseids and Orionids, produce high rates of meteors for a few days near their maximum. The Quadrantids are only highly active for 12-24 hours. As a result, the shower can be missed if the peak does not coincide with your early morning observing.

The peak time for this shower is always uncertain on the order of half a day or so and the IMO prediction calls for a peak some time between 21:00 UT on Jan 3 and 6:00 UT on Jan 4. This well placed for observers in Europe. Here in the US activity during the prime early morning hours should be rapidly tailing off.

Back in 2009 this shower put on a great show with the peak well observed from the US. Peak rates that year reached a ZHR of ~150-160. But in 2008, rates “only” reached into the 80s. With the Moon near New the sky will be dark. Who knows what we’ll get this year so we’ll just have to brave the cold and see.

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors. Starting this month, info on most of the minor showers will be provided on a weekly basis by Robert Lunsford’s Meteor Activity Outlook.

Additional information on these showers and other minor showers not included here can be found at the following sites: Wayne Hally’s and Mark Davis’s NAMN Notes, and the International Meteor Organization’s 2010 Meteor Shower Calendar.

Comets

Naked Eye Comets (V < 6.0)

None

Binocular Comets (V = 6.0 – 8.0)

None

Small Telescope Comets (V = 8.0 – 10.0)

Comet 103P/Hartley 2 – Comet 103P/Hartley 2 continues its retreat from the Earth and Sun. Well past its late October peak in brightness, the comet starts January around magnitude 8-9 and should steadily fade to around magnitude 9-10 by the end of the month.

.
103P was discovered at Siding Spring Observatory (Australia) on March 15, 1986 by  Malcolm Hartley. With an orbital period of 6.47 years, the comet’s orbit currently stretches from 1.06 AU to 5.89 AU from the Sun. Though not an especially big comet, this year it passed 0.12 AU from Earth on October 21 allowing the comet to get much brighter than usual.The comet starts the month at a distance of 1.37 AU from the Sun and 0.47 AU from Earth. By mid-month it will be 1.49 AU from the Sun and 0.57 AU from Earth. At the end of the month, Hartley 2 will be 1.62 AU and 0.73 AU from the Sun and Earth, respectively.
The comet is located in the southern part of the winter Milky Way. Slowly moving north 103P will spend most of the month in Canis Major before crossing the border back into Monoceros near the end of the month. It is a month past opposition and is highest in the sky during the middle of the night.
 

.

On November 4 the NASA EPOXI (ex-Deep Impact) spacecraft encountered Hartley 2 giving us close-up views of the comet’s nucleus. This is the xth comet visited by a spacecraft after Comets 21P/Giacobini-Zinner (1985), 1P/Halley (1986), 19P/Borelly (2001), 81P/Wild 2 (2004), 9P/Tempel 1 (2005). On February 15, 2011, Tempel 1 will be the first comet to be re-visited by a spacecraft.

A finder chart for Comet Hartley 2 can be found at Comet Chasing and Sky and Telescope.

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida’s Comet Homepage.

Asteroids

Binocular and Small Telescope Asteroids (V < 9.0)

(7) Iris

Iris is an inner Main-Belt asteroid that can occassionally get as bright as any asteroid. This year, Iris will not get as bright but will still become a binocular object at opposition on January 24 at magnitude 7.9. During December, it is located in the constellation of Cancer a few degrees to the southwest of the Beehive Cluster. It starts the month at magnitude 8.3, brightens to 7.9 at opposition on the 24th and then fades to 8.1 at the end of the month..

With a size of 240 x 200 x 200 km, Iris is the 5th largest stoney S-type asteroid. It was discovered in 1847 by John Russel Hind, the 1st of 10 asteroids he discovered.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Ceres from Heavens Above.

In The Sky This Month – December 2010

This feature highlights a number of meteor showers, comets and asteroids which are visible during the month of December 2010.

December 2010 Highlights
* Great Total Lunar Eclipse for the Americas and Eastern Asia on Dec 21
* Geminid Meteor Shower peaks on Dec 14
* Jupiter dominates the evening sky, while…
* Venus dominates the morning sky
* Comet 103P/Hartley 2 slowly fades as it moves away from the Earth and Sun

Note: If anyone has pictures or observations of these objects/events and want to share them with my readers, send them to the Transient Sky at <transientsky1@yahoo.com>.

Planets

Moon - The big event this month is a Total Lunar Eclipse on the night of Dec 20/21. The Moon will be located nearly overhead during the peak of the eclipse for North American observers.

The start of the umbral eclipse (when the darkest part of Earth’s shadow covers the Moon) will occur at 6:32 UT (1:32 EST / 12:32 CST / 11:32 MST / 10:32 PST) with mid-eclipse at 8:16 UT (3:16 EST / 2:16 CST / 1:16 MST / 12:16 PST)

The table below lists important lunar dates for the month, including the phases of the Moon and nights of lunar-planetary and lunar-stellar conjunctions.

Dec 1 - Moon 7° from Saturn
Dec 2 - Moon 6° from Venus and 3° from Spica
Dec 5 - New Moon
Dec 6 - Moon 0.8° from Mars
Dec 7 - Moon 2° from Mercury
Dec 11 - Moon 5° from Neptune
Dec 13 - First Quarter Moon 7° from Jupiter
Dec 14 - Moon 6° from Uranus
Dec 19 - Moon 1.5° from Pleiades and 8° from Aldebaran
Dec 21 - Full Moon and Total Lunar Eclipse
Dec 23 - Moon 8° from Pollux
Dec 24 - Moon 4° from Beehive Cluster
Dec 25 - Moon 5° from Regulus
Dec 28 - Third Quarter Moon 7° from Saturn
Dec 29 - Moon 3° from Spica
Dec 31 - Moon 7° from Venus

Mercury – Mercury is in the middle of a evening apparition at the start of the month. It’s all downhill (literally) after that as the innermost planet creeps back into the bright twilight and out of view by mid-month. At the end of the month Mercury is back as it peeks above the SE horizon right before dawn.

Dec 1 - Greatest Elongation East
Dec 7 - Moon 2° from Mercury 

Mars - Mars is practically out of view this month for most of us. Those with exceptionally clear skies and unobstructed view of the SW sky in the evening might still catch a glimpse of this +1.3 magnitude planet.

Dec 6 - Moon 0.8° from Mars

Jupiter (and Uranus, too...) - The 'King of the Planets' continues his reign as the uncontested 'King of the Evening Sky'. though fading from magnitude -2.5 to -2.3, nothing but the Moon rivals it in brightness. Located on the Pisces/Aquarius border, Jupiter is easy to find in the south-south-east as it gets dark.

If you have a pair of binoculars or small telescope take a look at Jupiter. See if you can see any of its 4 bright Galilean moons or its large atmospheric belts (there are usually 2 prominent belts but 1 has recently disappeared though it may make a comeback at any time). In addition, Jupiter is within 2.9° of +5.8 magnitude Uranus on Dec 1 and 0.7° on Dec 31.

Dec 13 - First Quarter Moon 7° from Jupiter

Saturn - Saturn rises a few hours before the Sun. Located in Virgo, the ringed planet is a close match in brightness (mag +0.9) to the Spica, the brightest star in Virgo (mag +1.0). Saturn spends the entire month within 9-10° of Spica. It's rings are slowly opening up and are currently 9° from edge-on.

Dec 1 - Moon 7° from Saturn
Dec 28 - Moon 7° from Saturn

Venus - After passing through inferior conjunction in late October , Venus is now the dominant sight in the morning sky. On Dec 1, Venus rises 3 hours before the Sun in the eastern sky. By the end of the month, it is up almost 4 hours before sunrise. Unlike this year's evening apparition which was poorly placed, Venus' current stay in the morning sky will be a good one for northern observers.

Dec 2 - Venus at its brightest (magnitude -4.5 to -4.9 depending on the source)
Dec 2 - Moon 6° from Venus
Dec 31 - Moon 7° from Venus

Meteors

Meteor activity is still quite high in December. The year is usually split in 2 with January through June having low rates with few major showers while July through December (really through the 1st week of January) have high rates with many major showers.

Sporadic Meteors

Sporadic meteors are not part of any known meteor shower. They represent the background flux of meteors. Except for the few days per year when a major shower is active, most meteors that are observed are Sporadics. This is especially true for meteors observed during the evening. During September, 10-16 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

Geminids (GEM) [Max Date = Dec 14, Max Rate = ~60-120 per hour under dark skies]

Along with the Perseids of August, the Geminids are one of the best meteor showers delivering great displays year after year. This year's Geminids are nicely timed with the First Quarter Moon will be setting around midnight.

According to Sirko Molau's analysis of video data, the Geminids are already observable at the beginning of the month though their rates are very low. The peak is predicted for the night of December 13/14 though numerous meteors should be visible for a day or two on either side of the peak. With a radiant near the star Castor in the constellation of Gemini, the Geminids are one of the rare major showers that are observable before midnight and can be observed as early as 8:00 pm though rates are usually best after 10:00 pm (though with the caveat for this year that the Moon will spoil the show until it sets around midnight). Under a dark rural moon-less sky, the Geminids can produce as many as 100+ meteors per hour. Observers under suburban skies will see lower rates.

The Geminids are the result of the break-up and subsequent activity of the "asteroid" (3200) Phaethon. Why asteroid in quotes? Most meteor showers come from comets yet Phaethon is on a very non-cometary orbit and has never shown any cometary activity. There is still much scientific discussion about what exactly Phaethon is.

More details on the Geminids and their parent "asteroid" Phaethon will be posted as we get closer to its peak.

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors. Starting this month, info on most of the minor showers will be provided on a weekly basis by Robert Lunsford's Meteor Activity Outlook.

Additional information on these showers and other minor showers not included here can be found at the following sites: Wayne Hally's and Mark Davis's NAMN Notes, and the International Meteor Organization's 2010 Meteor Shower Calendar.

Comets

Naked Eye Comets (V < 6.0)

None

Binocular Comets (V = 6.0 - 8.0)

Comet 103P/Hartley 2 - Comet 103P/Hartley 2 continues its retreat from the Earth and Sun. Well past its late October peak in brightness, the comet starts December around magnitude 6 and should steadily fade to around magnitude 8 by the end of the month.

.103P was discovered at Siding Spring Observatory (Australia) on March 15, 1986 by  Malcolm Hartley. With an orbital period of 6.47 years, the comet's orbit currently stretches from 1.06 AU to 5.89 AU from the Sun. Though not an especially big comet, this year it passed 0.12 AU from Earth on October 21 allowing the comet to get much brighter than usual.The comet starts the month at a distance of 1.16 AU from the Sun and 0.29 AU from Earth. By mid-month it will be 1.24 AU from the Sun and 0.36 AU from Earth. At the end of the month, Hartley 2 will be 1.36 AU and 0.46 AU from the Sun and Earth, respectively. 

Even though the comet is currently 6th magnitude and theoretically bright enough to be an easy binocular object, in reality this is a difficult object to observe. With a coma diameter approaching 1° across, the light of the comet is spread over a wide area. As a result, even small amounts of light pollution renders much of the coma invisible. Dark skies are always a plus and will help in observing this challenging comet.

The comet is located in the southern part of the winter Milky Way. The start of December sees the comet in Puppis just to the south of the bright open clusters M46 and M47. By the end of the month it will have retrograded into Canis Major. It is a morning object and is visible after midnight.

.

On November 4 the NASA EPOXI (ex-Deep Impact) spacecraft encountered Hartley 2 giving us close-up views of the comet's nucleus. This is the xth comet visited by a spacecraft after Comets 21P/Giacobini-Zinner (1985), 1P/Halley (1986), 19P/Borelly (2001), 81P/Wild 2 (2004), 9P/Tempel 1 (2005). On February 15, 2011, Tempel 1 will be the first comet to be re-visited by a spacecraft.

A finder chart for Comet Hartley 2 can be found at Comet Chasing and Sky and Telescope.

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida's Comet Homepage.

Small Telescope Comets (V = 8.0 - 10.0)

Comet P/2010 V1 (Ikeya-Murakami) - Probably the surprise comet of the year, Comet Ikeya-Murakami is a rare visual find. Not long ago most bright comets were discovered by amateur astronomers visually through the eyepiece of their telescopes without the help of computers. Nowadays, the professional surveys are able to scan large swathes of sky and with the help of digital CCD cameras and detection software find most comets.

The reason Ikeya and Murakami could discover P/2010 V1 is probably because it is a small and usually weakly or even inactive comet. The fact that the comet was not visible to other comet hunters (including Ikeya) a day or two before discovery suggests it has recently undergone an outburst. CCD images of its rapidly expanding coma also point to a recent event. At discovery the comet was as bright as magnitude 7.5 to 8.0. At the start of this month the comet is around magnitude 9 to 10 and, baring another outburst, should quickly fade.

Another interesting thing about this comet is its orbit. With an aphelion of only ~4.2 AU, the comet does not extend far enough to reach the orbit of Jupiter. Unlike most cometary orbits, this orbit is very asteroidal and suggests that it more closely related to volatile-rich Main belt comets than the typical comet from the outer Solar System.

Perihelion occurred on 2010 Oct. 11 at 1.57 AU. The comet is now outbound and at mid-month is located 1.68 AU from the Sun and 2.21 AU from Earth. Starting the month in Virgo the comet will cross into Libra by mid-month.

A finder chart for Comet Ikeya-Murakami can be found at Comet Chasing.

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida's Comet Homepage.

Asteroids

Binocular and Small Telescope Asteroids (V < 9.0)

(7) Iris

Iris is an inner Main-Belt asteroid that can occassionally get as bright as any asteroid. This year, Iris will not get as bright but will still become a binocular object at opposition on January 24 at magnitude 7.9. During December, it is located in the constellation of Cancer a few degrees to the southwest of the Beehive Cluster. It starts the month at magnitude 8.9 and ends it at magnitude 8.3.

With a size of 240 x 200 x 200 km, Iris is the 5th largest stoney S-type asteroid. It was discovered in 1847 by John Russel Hind, the 1st of 10 asteroids he discovered.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Ceres from Heavens Above.

In The Sky This Month – November 2010

This feature highlights a number of meteor showers, comets and asteroids which are visible during the month of November 2010.

November 2010 Highlights
* Comet 103P/Hartley 2 is still a naked eye object (though fading) under very dark skies
* Jupiter dominates the eastern evening sky
* Uranus remains within 3 degrees of Jupiter all month
* Venus rockets into the morning sky
* Leonids meteor shower has a weak peak on the 17th

Note: If anyone has pictures or observations of these objects/events and want to share them with my readers, send them to the Transient Sky at <transientsky1@yahoo.com>.

Planets

Moon - The table below lists important lunar dates for the month, including the phases of the Moon and nights of lunar-planetary and lunar-stellar conjunctions.

Nov 1 - Moon 5° from Regulus
Nov 4 - Moon 7° from Saturn and 3° from Spica
Nov 5 - Moon 1° from Venus (but 12° from Sun)
Nov 6 - New Moon
Nov 7 - Moon 2° from Mars
Nov 8 - Moon 3° from Antares
Nov 13 - First Quarter 
Nov 16 - Moon 7° from Jupiter and 6° from Uranus
Nov 21 - Full Moon
Nov 21 - Moon 2° from Pleiades
Nov 22 - Moon 8° from Aldebaran
Nov 25 - Moon 9° from Pollux
Nov 26 - Moon 4° from Beehive Cluster
Nov 28 - Last Quarter
Nov 28 - Moon 5° from Regulus

Mercury – Mercury pops above the southwestern horizon around mid-month for a relatively poor evening apparition for northern observers (it is a pretty good one for those south of the equator). For most of the month Mercury hangs out with Mars and Antares. At magnitude -0.4, it is much brighter than the ‘Red Planet’. This evening apparition will continue into December.

Nov 15 - Mercury, Mars and Antares can fit within a 5° circle
Nov 20 - Mars and Mercury within 2° of each other 

Mars – Mars has fun this month with conjunctions with Mercury and 1st magnitude star Antares. Unfortunately, you’ll need an ultra-flat and ultra-clear southwestern horizon to see any of this. For most of us, the current Martian apparition is over. For the next few months the planet will be on the far side of the Sun and out of view.

Nov 7 - Mars 2° from the Moon
Nov 11 - Mars 4° from Antares 
Nov 15 - Mercury, Mars and Antares can fit within a 5° circle
Nov 20 - Mars and Mercury within 2° of each other 

Jupiter (and Uranus, too…) – ‘King of the Planets’ continues his reign as the uncontested ‘King of the Evening Sky’. though fading from magnitude -2.8 to -2.6, nothing but the Moon rivals it in brightness. Located on the Pisces/Aquarius border, Jupiter is easy to find in the south-south-east as it gets dark.

If you have a pair of binoculars or small telescope take a look at Jupiter. See if you can see any of its 4 bright Galilean moons or 2 large atmospheric belts. In addition, Jupiter is within 3.4° of +5.8 magnitude Uranus all month long.

Nov 16 - Moon within 7° of Jupiter and 6° of Uranus

Saturn – Saturn rises a few hours before the Sun. Located in Virgo, the ringed planet is a close match in brightness (mag +0.9) to the Spica, the brightest star in Virgo (mag +1.0). It’s rings are slowly opening up and are currently 9° from edge-on.

Nov 4 - Saturn within 7° of the Moon

Venus – After passing through inferior conjunction last month, Venus begins a 10-month stay in the morning sky. On Nov 1, Venus rises only a half an hour before the Sun in the eastern sky. By the middle of the month, it is up 2 hours before sunrise and 3 hours before sunrise by the end of the month. Unlike this year’s evening apparition which was poorly placed, Venus’ current stay in the morning sky will be a good one for northern observers.

Nov 5 - Moon 1° from Venus (but 12° from Sun)

Meteors

Meteor activity is near a yearly maximum in October. The year is usually split in 2 with January through June having low rates with few major showers while July through December (really through the 1st week of January) have high rates with many major showers.

Sporadic Meteors

Sporadic meteors are not part of any known meteor shower. They represent the background flux of meteors. Except for the few days per year when a major shower is active, most meteors that are observed are Sporadics. This is especially true for meteors observed during the evening. During September, 10-16 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

Leonids (ORI) [Max Date = Nov 17, Max Rate = ~10-20 per hour]

The Leonids are the only November shower which can approach major shower status. Though this shower has produced some of the greatest meteor storms in history, in most year’s it produces a rather pedestrian 10-20 meteors per hour under dark skies. Now that we are 12 years removed from the last perihelion of Comet Tempel-Tuttle, the parent comet of the Leonids, rates should be low with little likelihood of any enhanced activity.

The following summary from the IMO  2010 Meteor Calendar states: “This year is not expected to produce enhanced rates, but theoretical work by Mikhail Maslov suggested peak ZHRs of ~ 20 might occur around November 17, 15h UT instead of at the usual nodal crossing time above [Nov 17, 21:15 UT]. ZHRs from that later possible peak are likely to be ~ 10–20. The waxing gibbous Moon will not set until 2 to 3 a.m. local time on November 17 across the mid-latitude globe (later moonsets for places further north). As the Leonid radiant rises usefully only around local midnight (or indeed afterwards south of the equator), there will still be plenty of dark-sky time between moonset and the onset of morning twilight to observe whatever happens this year. The ~ 15h UT peak timing would coincide with moonless skies from the extreme east of Russia east to Alaska and places at similar longitudes on the Pacific Ocean. The ~ 21h UT timing would favour locations at comparable longitudes to central-eastern Asia, from roughly India east to Japan/western Australia. Other possible maxima are not excluded, and observers should be alert as often as conditions allow throughout the shower, in case something unexpected happens.”

The Leonids appear to radiate from a spot in the ‘sickle’ of Leo. Like many showers, the radiant does not rise till after midnight and is not well placed until after 3 am.

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors. Starting this month, info on most of the minor showers will be provided on a weekly basis by Robert Lunsford’s Meteor Activity Outlook.

Additional information on these showers and other minor showers not included here can be found at the following sites: Wayne Hally’s and Mark Davis’s NAMN Notes, and the International Meteor Organization’s 2010 Meteor Shower Calendar.

Comets

Naked Eye Comets (V < 6.0)

Comet 103P/Hartley 2 – Comet 103P/Hartley 2 is now in retreat from the Earth and Sun. Though past peak brightness the comet starts the month only a few tenths of a magnitude fainter than at its best (around magnitude +4.7). By the end of the month the comet will have faded by a magnitude or more.

103P was discovered at Siding Spring Observatory (Australia) on March 15, 1986 by  Malcolm Hartley. With an orbital period of 6.47 years, the comet’s orbit currently stretches from 1.06 AU to 5.89 AU from the Sun. Though not an especially big or active comet, this year it passes 0.12 AU from Earth on October 21 allowing the comet to get much brighter than usual.

The comet starts the month at a distance of 1.06 AU from the Sun and 0.14 AU from Earth. By mid-month it will be 1.09 AU from the Sun and 0.20 AU from Earth. At the end of the month, Hartley 2 will be 1.15 AU and 0.28 AU from the Sun and Earth, respectively.

Even though the comet is currently 4th to 5th magnitude and theoretically bright enough to be seen with the naked eye, in reality this is a difficult object to observe. With a coma diameter greater than 1° across, Under very dark skies the comet can be seen with the naked eye. For most of us under brighter skies, the comet is not visible naked eye object but is visible in small binoculars as a large (30′+) diffuse fuzz ball. Under my moderately light polluted sky (LM +5.5), the comet was a faint but easy object in 10×50 binoculars if you know exactly where to look. As always, the darker the sky the better.

The comet is still racing south along the winter Milky Way. It starts the month in southern Gemini before crossing through Canis Minor and Monoceros and ending the month in Puppis between the bright open clusters M46 and M47. It is a morning object and is highest in the sky before the start of dawn.

.

On November 4 the NASA EPOXI (ex-Deep Impact) spacecraft will encounter the comet giving us close-up views of the comet’s nucleus.

A finder chart for Comet Hartley 2 can be found at Comet Chasing and Sky and Telescope.

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida’s Comet Homepage.

Binocular Comets (V = 6.0 – 8.0)

None

Small Telescope Comets (V = 8.0 – 10.0)

None

Asteroids

Binocular and Small Telescope Asteroids (V < 9.0)

(6) Hebe

(6) Hebe is a S-type asteroid with dimensions 205 x 185 x 170 km. Recent research suggests that it is the source of many ordinary chondrite meteorites and near-Earth asteroids.

This month Hebe is in Cetus and will fade from magnitude 8.4 to 9.0.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Hebe from Heavens Above.

Moon and Jupiter This Evening

This week Comet Hartley 2 is at its biggest and brightest and the Moon will wreck the show. This week the Orionid meteor shower is at its best and the Moon will wreck the show. But at least the Moon will  give us a consolation prize tonight as it teams up with the King of the Planets this evening.

Right after it gets dark this evening check out the Moon in the eastern sky. That brilliant ‘star’ below it is the planet Jupiter. If you have a pair of binoculars check out Jupiter up close. See if you can tell that Jupiter is a small globe rather than just a stellar point. Count how many of its 4 Galilean satellites are visible nearby. For a real challenge hunt for 5th magnitude Uranus only a few degrees away. For a finder chart for Uranus go here.

In the Sky This Month – October 2010

This feature highlights a number of meteor showers, comets and asteroids which are visible during the month of October 2010.

October 2010 Highlights 
* Comet 103P/Hartley 2 is a naked eye object under very dark skies
* Jupiter dominates the eastern evening sky
* Uranus remains within 3 degrees of Jupiter all month
* Orionids meteor shower will be washed out by bright Moonlight

Note: If anyone has pictures or observations of these objects/events and want to share them with my readers, send them to the Transient Sky at <transientsky1@yahoo.com>.

Planets

Moon - The table below lists important lunar dates for the month, including the phases of the Moon and nights of lunar-planetary and lunar-stellar conjunctions.

October 1 - Last Quarter 
October 2 - Moon 8° from Pollux 
October 3 - Moon 4° from Beehive Cluster 
October 4 - Moon 5° from Regulus
October 7 - New Moon 
October 9 - Moon 3° from Venus
October 10 - Moon 3° from Mars
October 11 - Moon 3° from Antares 
October 14 - First Quarter  
October 20 - Moon 7° from Jupiter and Uranus
October 23 - Full Moon
October 25 - Moon 1.5° from Pleiades 
October 26 - Moon 8° from Aldebaran
October 29 - Moon 8° from Pollux
October 30 - Last Quarter
October 30 - Moon 4° from Beehive Cluster

Venus – Venus starts the month very low in the SW sky at sunset. By the end of twilight it has already set. Conditions only get worse as it descends towards the Sun. By mid-month, Venus is invisible in the evening sky. After passing inferior conjunction on the 29th, Venus will rapidly climb higher in the morning sky and should be visible by early next month.

October 1 - Venus 7° S of Mars
October 9 - Moon passes within 3.4° of Venus 
October 29 - Venus at inferior conjunction

Mars – Mars continues its slow grind lower in the southwestern evening sky. At a relatively faint (for a planet anyway) magnitude of +1.5, Mars is only visible low in the SW during evening twilight.

October 1 - Mars 7° N of Venus
October 10 - Moon passes within 3° of Mars

Jupiter (and Uranus, too…) – This month the ‘King of the Planets’ is also the ‘King of the Evening Sky’. At magnitude -2.8 Jupiter is the brightest ‘star’ in the eastern evening sky. It is currently located on the Pisces/Aquarius border.

If you have a pair of binoculars or small telescope take a look at Jupiter. See if you can see any of its 4 bright Galilean moons or 2 large atmospheric belts. In addition, Jupiter is within 3° of +5.7 magnitude Uranus all month long.

October 20 - Moon within 7° of Jupiter and 6° of Uranus

Saturn – Saturn starts the month behind the Sun. By the end of the month, the +0.9 magnitude planet can be seen very low  in the eastern sky during dawn. It is currently located in Virgo and will be for the next year or so.

October 1 - Saturn at conjunction with Sun

Mercury - Mercury is rapidly dropping towards the Sun at the beginning of the month. By  the end of the first week of October it will be too close to the Sun to be seen.

October 17 - Mercury at Superior Conjunction

Meteors

Meteor activity is near a yearly maximum in October. The year is usually split in 2 with January through June having low rates with few major showers while July through December (really through the 1st week of January) have high rates with many major showers.

Sporadic Meteors

Sporadic meteors are not part of any known meteor shower. They represent the background flux of meteors. Except for the few days per year when a major shower is active, most meteors that are observed are Sporadics. This is especially true for meteors observed during the evening. During September, 10-16 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

Orionids (ORI) [Max Date = Oct 21, Max Rate = ~20-70 per hour]

The Orionids are one of the most reliable and productive showers of the year. Another point in their favor, is their high level of activity over the course of ~5 nights or so. This gives ample opportunity to catch a few Orionid meteors. Unfortunately this year the nearly Full Moon will severely hamper watching this shower.

The meteors that make up the Orionid shower were originally released by the one comet everyone has heard of, Comet Halley. Computer simulations of the past movements of Halley and its dust suggest that many of this year’s Orionid meteors were released by Halley between 1265 BC and 910 BC (for some points of reference, the Trojan War took place around 1200 BC and King David ruled around 1000 BC).

The Orionids are usually active from Oct 3 to Nov 11 with a broad peak between Oct 18 and 24. During their peak, rates can be as high as 20-70 meteors per hour. During the last  two years rates reached 40-45 meteors per hour which is nearly half the rate observed in 2007 (70 per hour). With a bright Moon-lit sky, actual rates will be much lower making this a dificult year to see the Orionids.

The Orionids appear to come from an area in northern Orion. This area, called the radiant, rises around 10pm local time. It is best to wait till the radiant is high in the sky before looking for meteors (say 1am). The radiant is highest around 3:30am which is the best time to look. As you can see on the sky chart, the Moon is almost on top of the radiant. Meteors can appear anywhere in the sky so you don’t have to look at the radiant.

More can be found at earlier Orionids posting from 2008 and 2009.

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors. Starting this month, info on most of the minor showers will be provided on a weekly basis by Robert Lunsford’s Meteor Activity Outlook.

Additional information on these showers and other minor showers not included here can be found at the following sites: Wayne Hally’s and Mark Davis’s NAMN Notes, and the International Meteor Organization’s 2010 Meteor Shower Calendar.

Comets

Naked Eye Comets (V < 6.0)

Comet 103P/Hartley 2 – Comet 103P/Hartley 2 should be the comet of the year. Currently as bright as magnitude +5.5 to +6.5 magnitude, naked eye sightings of this comet have already been reported from very dark sites. The comet will continue to brighten during the course of the month.

.

103P was discovered at Siding Spring Observatory (Australia) on March 15, 1986 by  Malcolm Hartley. With an orbital period of 6.47 years, the comet’s orbit currently stretches from 1.06 AU to 5.89 AU from the Sun. Though not an especially big or active comet, this year it passes 0.12 AU from Earth on October 21 allowing the comet to get much brighter than usual.

The comet starts the month at a distance of 1.12 AU from the Sun and 0.18 AU from Earth. By mid-month it has moved into Andromeda and will be 1.21 AU from the Sun and 0.29 AU from Earth. Closest approach to Earth occurs on October 21 at 0.12 AU while closest approach to the Sun happens on October 28 at 1.06 AU. At the end of the month, Hartley 2 will be 1.06 AU and 0.14 AU from the Sun and Earth, respectively.

Last month there was concern that the comet was running much fainter than expected. Due to the large diffuse nature of its coma, many observers were underestimating the brightness of the comet. The comet still appears to be a little fainter than predicted but it should still brighten to a nice magnitude +4.5 to +5.0 by the end of October.

Under very dark skies the comet can already be seen with the naked eye. For most of the rest of us, Hartley 2 is a large (30′+) diffuse fuzz ball. Under my moderately light polluted sky (LM +5.5), the comet was a difficult object in 10×50 binoculars. As always, the darker the sky the better.

The comet is traversing the winter Milky Way and starts the month in Cassiopeia before running the length of Perseus and Auriga and ending the month in Gemini. It is visible all night long at the start of the month but becomes solely a morning object by mid-month.

.

In early November the NASA EPOXI (ex-Deep Impact) spacecraft will encounter the comet giving us close-up views of the comet’s nucleus.

A finder chart for Comet Hartley 2 can be found at Comet Chasing and Sky and Telescope.

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida’s Comet Homepage.

Binocular Comets (V = 6.0 – 8.0)

None

Small Telescope Comets (V = 8.0 – 10.0)

None

Asteroids

Binocular and Small Telescope Asteroids (V < 9.0)

(6) Hebe and (8) Flora

These 2 large inner Main Belt asteroids will move in tandem this fall. Both are S-type asteroids with similar compositions and albedos. (6) Hebe is the larger of the pair (205 x 185 x 170 km). Recent research suggests that it is the source of many ordinary chondrite meteorites and near-Earth asteroids. (8) Flora is a little smaller (136 x 136 x 113 km) and is the largest surviving member of a numerous asteroid family created by a long ago impact.

This month Hebe is retrograding in Cetus and will fade from magnitude 7.7 to 8.4. Just across the border in Aquarius Flora fades from magnitude 8.5 to 9.1.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Hebe from Heavens Above.

Around the Sky in 28 Days – Days 14-16

Tonight marks the Full Moon (9:18 UT, 2:18 am PDT, 3:18 am MDT, 4:18 am CDT, 5:18 am EDT). But that’s not it! Today is also the 1st day of Spring. Also both Jupiter and Uranus were at opposition only  2 days ago. As a result, the 1st Full Moon of autumn is located right next to a brilliant Jupiter and an easy to find Uranus.

The charts below show the location of the Moon, Jupiter and Uranus for the next 3 nights. Each chart is for the early evening a few hours after sunset.

Eastern sky a few hours after sunset on Sept. 22.

Eastern sky a few hours after sunset on Sept. 23.

Eastern sky a few hours after sunset on Sept. 24.

.

Definitely take the opportunity to use a pair of binoculars or a telescope to take a peak at Jupiter. The planet is large enough to appear as a small globe even in the smallest of instruments. Also obvious are its 4 Galilean satellites (Io, Europa, Ganymede and Callisto). The moons are surprisingly bright at 4th-5th magnitude and would be easy naked eye objects under a dark sky if they weren’t swamped by the glow of Jupiter. Note, all 4 moons may not be visible at any particular time since the moons can be located behind or even in front of Jupiter’s disk. The chart below shows the positions of the moons in the early evening of the 22nd.

Uranus is as bright as the faintest Galilean satellites and located not that much further away from Jupiter. While Jupiter is located 3.95 AU from Earth (about as close as it can get), Uranus is farther away at a distance of 19.09 AU. In small scopes, Uranus will probably look like a green star. At high magnifications one might notice the planet as a very small disk.

In The Sky This Month – September 2010

This feature highlights a number of meteor showers, comets and asteroids which are visible during the month of September 2010.

September 2010 Highlights

* Venus, Mars and Spica together in evening sky at start of month
* The above 3 joined by the Moon on the 11th
* Jupiter at opposition (21st) with Full Moon (23rd) and Uranus nearby
* Mercury has a good morning apparition
* Comet 103P/Hartley 2 is bright enough for small telescopes and binoculars

Note: If anyone has pictures or observations of these objects/events and want to share them with my readers, send them to the Transient Sky at <transientsky1@yahoo.com>.

Planets

Moon - This month brings a new addition to the “In The Sky This Month” lineup. The table below lists important lunar dates for the month, including the phases of the Moon and nights of lunar-planetary and lunar-stellar conjunctions.

September 1 - Last Quarter
September 1 - Moon 1° South of Pleiades
September 1 - Moon 8° North of Aldebaran
September 4 - Moon 8° SSW of Pollux
September 5 - Moon 4° SSW of Beehive Cluster
September 8 - New Moon
September 9 - Moon 7° SSW of Saturn
September 10 - Moon 3° SSW of Spica
September 11 - Moon 5° SSW of Mars
September 12 - Moon 0.6° from Venus
September 14 - Moon 2° NNW of Antares
September 15 - First Quarter
September 23 - Full Moon
September 23 - Moon 7° from Jupiter
September 28 - Moon 1.5° from Pleiades
September 29 - Moon 8° North of Aldebaran

Saturn – Saturn is located low in the west during evening twilight. By month’s end the +1.0 magnitude planet will be too close to the Sun to be seen easily by most observers.

September 9 - Moon within 7° of Saturn

Mars – Mars is the second of three planets visible in the west after sundown. This month +1.5 magnitude Mars starts a few degrees to the upper right of brilliant Venus. Though the planets will slowly move apart they will stay within 7° of each other all month long.

September 11 - Moon passes within 5° of Mars

Venus – Venus is the third and by far the brightest planet visible in the early evening (at magnitude -4.6 to -4.8). For northern observers this is a poor apparition. Though the planet is at its brightest and located almost as far from the Sun as it gets, the angle between the ecliptic and the horizon results in the planet staying close to the horizon. A clear view of the WSW horizon is needed in order to see Venus (and Mars and Saturn, as well). The planet sets 1.5 hours after sunset at the start of September and less than an hour by the end of the month. See the notes in the Mars section above about seeing Mars in the vicinity of Venus.

September 1 - Venus within 1° of Spica
September 11 - Moon passes within 0.6° of Venus
September 27 - Venus at its brightest (magnitude -4.6)

Jupiter (and Uranus, too…) – This month Jupiter rules the heavens. On the 21st, the ‘King of the Planets’ will be at opposition (meaning it is located directly opposite the Sun on the sky). All month Jupiter will shine at its brightest (near magnitude -2.9). Opposition also means it will be visible all night long, rising in the evening, reaching its highest elevation around midnight and setting during dawn.

If you have a pair of binoculars or small telescope take a look at Jupiter. See if you can see any of its 4 bright Galilean moons or 2 large atmospheric belts. In addition, Jupiter is within a degree of +5.7 magnitude Uranus all month long.

September 18 - Jupiter and Uranus within 0.8° of each other
September 21 - Jupiter and Uranus at opposition
September 23 - Moon within 7 of Jupiter and 6 of Uranus

Mercury - Mercury starts the month too close to the Sun to be seen. By mid-month, it is in the midst of its best morning apparition (for northern observers).

September 19 - Mercury at Greatest Elongation West (18 from Sun)

Meteors

Meteor activity is near a yearly maximum in September. The year is usually split in 2 with January through June having low rates with few major showers while July through December (really through the 1st week of January) have high rates with many major showers.

Sporadic Meteors

Sporadic meteors are not part of any known meteor shower. They represent the background flux of meteors. Except for the few days per year when a major shower is active, most meteors that are observed are Sporadics. This is especially true for meteors observed during the evening. During September, 10-16 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

No major showers this month.

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors. Starting this month, info on most of the minor showers will be provided on a weekly basis by Robert Lunsford’s Meteor Activity Outlook.

Additional information on these showers and other minor showers not included here can be found at the following sites: Wayne Hally’s and Mark Davis’s NAMN Notes, and the International Meteor Organization’s 2010 Meteor Shower Calendar.

Comets

Naked Eye Comets (V < 6.0)

None

Binocular Comets (V = 6.0 – 8.0)

Comet 103P/Hartley 2

If it behaves as expected, Comet 103P/Hartley 2 should be the comet of the year. Currently magnitude +11.5, the comet is predicted to reach naked eye visibility (for dark sky observers) in October/November.

103P was discovered at Siding Spring Observatory (Australia) on March 15, 1986 by  Malcolm Hartley. With an orbital period of 6.47 years, the comet’s orbit currently stretches from 1.06 AU to 5.89 AU from the Sun. Though not an especially big or active comet, this year it passes 0.12 AU from Earth on October 21 allowing the comet to get much brighter than usual.

The comet starts the month in the faint constellation of Lacerta at a distance of 1.31 AU from the Sun and 0.39 AU from Earth. By mid-month it has moved into Andromeda and will be 1.21 AU from the Sun and 0.29 AU from Earth. By month’s end, the comet will just south of the brightest star in Cassiopeia (Alpha Cas) and 1.13 AU from the Sun and 0.19 AU from Earth.

[Note: The following paragraph has been updated to reflect recent observations.]

Now that the Moon is out of the morning sky, visual observers have been able to estimate the brightness of the comet. Observations over the past few days show the comet to be around magnitude 8.5. This is very close to its predicted brightness and suggests the comet may live up to its expected maximum brightness of 5th or 6th magnitude this Oct/Nov. The comet is large and diffuse with much of its brightness contained in a large, faint outer coma. As a result, the comet may appear much fainter to observers using large telescopes or observing from bright sites. By the end of the month the comet should be around magnitude 6.5 making it an easy binocular object.

In early November the NASA EPOXI (ex-Deep Impact) spacecraft will encounter the comet giving us close-up views of the comet’s nucleus.

A finder chart for Comet Hartley 2 can be found at Comet Chasing.

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida’s Comet Homepage.

Small Telescope Comets (V = 8.0 – 10.0)

Comet 10P/Tempel 2

’10P’ says it all. This was only the 10th comet to be observed at a 2nd apparition meaning we’ve been following this comet for a long time. Discovered by prolific German comet discoverer Ernst Wilhelm Leberecht Tempel in Marseille, France on July 4, 1873, Tempel 2 has been observed at nearly every return since then. The comet’s current orbit brings it to within 1.42 AU of the Sun on July 4 and to within 0.65 AU of Earth in late August.

The comet is currently at a brightness of 9.0 to 9.5 magnitude. This is a large diffuse object so it will be more difficult to see than your average 9th magnitude comet or deep sky object. From my moderately light polluted backyard and 12″ telescope, the comet was a difficult object and was estimated to be magnitude 10.0. From a dark site and 30×125 binoculars, the comet was much brighter (magnitude 9.5), larger and easier to see. The added brightness was probably due to the dark site allowing me to see much more of the comet’s coma.

At mid-month the comet will be 1.61 AU from the Sun and 0.67 AU from Earth. Tempel 2 is a morning object moving through the constellation of Cetus.

A finder chart for Comet Tempel 2 can be found at Comet Chasing.

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida’s Comet Homepage.

Asteroids

Binocular and Small Telescope Asteroids (V < 9.0)

(1) Ceres

Ceres is the biggest asteroid in the Main Belt with a diameter of 585 miles or 975 km. It is so big that it is now considered a Dwarf Planet. Classified as a carbonaceous (carbon-rich) Cg-type asteroid, there are suggestions that it may be rich in volatile material such as water. Some even propose that an ocean exists below its surface. Ceres is the other target of NASA’s Dawn spacecraft which is scheduled to visit it in 2015.

This month Ceres is an evening object moving from Ophiuchus into Saggitarius. The asteroid will start the month at magnitude 8.6 and fade to magnitude 9.0 by the end of the month.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Ceres from Heavens Above.

(6) Hebe and (8) Flora

These 2 large inner Main Belt asteroids will move in tandem this fall. Both are S-type asteroids with similar compositions and albedos. (6) Hebe is the larger of the pair (205 x 185 x 170 km). Recent research suggests that it is the source of many ordinary chondrite meteorites and near-Earth asteroids. (8) Flora is a little smaller (136 x 136 x 113 km) and is the largest surviving member of a numerous asteroid family created by a long ago impact.

This month Hebe is retrograding in Cetus and will brighten from magnitude 8.0 to 7.7. Just across the border in Aquarius Flora will brighten from magnitude 8.4 and peak at magnitude 8.2 in early September before fading back to 8.4 at the end of the month.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Hebe from Heavens Above.

In the Sky This Month – January 2010

This feature highlights a number of meteor showers, comets and asteroids which are visible during the month of January 2010. Mars is at its closest and brightest towards the end of the month. Bright red Mars anchors the eastern sky in the early evening while even brighter yellow Jupiter rules the western sky. The month’s single major meteor shower, the Quadrantids, will be washed out by bright moonlight (they will have already passed by the time you read this due to this entry’s late posting).

Note: If anyone has pictures or observations of these objects/events and want to share them, send me a comment and I’ll post them on the blog.

Planets

Mercury and Venus - Both planets start the month to close to the Sun for observation. Venus slowly moves into the evening sky after ~9 months in the morning sky. By month’s end it will still be a very difficult object to observe. Only those with a clear sky and no obstructions on their WSW horizon have a chance of catching Venus a few minutes after sunset. This coming evening apparition will allow for easy Venus viewing from March through September. For observers in the Southern Hemisphere this will be a great apparition, especially from July to October.

Mercury is traveling the other way and will pop out in the morning sky by mid-month. It will be located in the SE sky an hour or less before sunrise. This apparition is also better for southern observers.

Jan 4 - Mercury at Inferior conjunction
Jan 11 - Venus at Superior conjunction
Jan 27 - Mercury at Greatest elongation (West/Morning)

Jupiter - Jupiter is slowly sinking in the SW sky during the early evening hours. At magnitude -2.1, Jupiter is still many times brighter than the brightest stars. This is the last month to easily see the king of the planets.

  Jan 18 - Moon passes 4° from Jupiter

Neptune – Jupiter is rapidly pulling away from Neptune after the third of their 3 conjunctions last year. As a result, it is getting harder to use Jupiter as a guide to locate Neptune. A detailed PDF star chart for finding Neptune can be downloaded at the end of this Sky & Telescope article.

Uranus – Uranus is located in western Pisces and is bright enough to be seen in small binoculars at magnitude +5.9 but will still require a telescope in order to see it as anything other than a star (it’s disk is only 3.5″ across). A detailed PDF star chart for finding Uranus can be downloaded at the end of this Sky & Telescope article.

Mars – This month Mars is at opposition (the point opposite the Sun in the sky) on January 29. Opposition means Mars is closest to Earth and at its brightest. It also means it is visible nearly all night long, rising in east in the early evening, at its highest around midnight, and setting in the west around dawn.

Mars spends the whole month retrograding (moving from east to west) in the constellation of Cancer. Already a bright magnitude -0.7 at the start of the month, Mars will peak at magnitude -1.3 on opposition before slightly fading to -1.2 by month’s end. It’s opposition brightness almost matches that of Sirius, the brightest star. Note that unlike the stars which twinkle, Mars shines with an unwavering red glow.

Jan 3 - Moon passes close (6°) to Mars
Jan 27 - Closest to Earth (0.664 AU)
Jan 29 - Opposition
Jan 30 - Moon passes close (6°) to Mars

Saturn – Saturn is easy to observe during the morning hours and is sufficiently high enough to be observed in the eastern sky by midnight. Located in Virgo, the planets will appear as bright as a magnitude +0.8 star. Telescope users should note that Saturn’s rings are still close to edge-on.

Jan 6 - Moon and Saturn within 7° of each other

Meteors

January hosts one of the better annual showers of the year in the Quadrantids. Unfortunately this year’s display will be wrecked by bright moonlight. The background rate of meteors crashes in January.  The year is usually split in 2 with January through June having low rates with few major showers while July through December (really through the 1st week of January) have high rates with many major showers.

Sporadic Meteors

Sporadic meteors are not part of any known meteor shower. They represent the background flux of meteors. Except for the few days per year when a major shower is active, most meteors that are observed are Sporadics. This is especially true for meteors observed during the evening. During January, 8-10 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

Quadrantids (QUA)

The Quadrantids are the best shower that you’ve probably never heard of. It’s bad enough that this shower peaks in the middle of winter in the northern hemisphere, but it is also named after a long defunct constellation. When first identified in the early 1800s, the meteors were observed to radiate from the small faint constellation of Quadrans Muralis (the Mural Quadrant). Unfortunately, the constellation didn’t make the cut when the official list of 80 constellations was set in 1930. Today, Quadrans Muralis and the radiant of the Quadrantids can be found north of the constellation of Bootes.

Another strike against observing the Quadrantids is their short duration. Showers, like the Perseids and Orionids, produce high rates of meteors for a few days near their maximum. The Quadrantids are only highly active for 12-24 hours. As a result, the shower can be missed if the peak does not coincide with your early morning observing.

This years display was predicted to peak on the night of Jan 2/3. A very bright nearly full Moon will keep rates very low.

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors. Starting this month, info on most of the minor showers will be provided on a weekly basis by Robert Lunsford’s Meteor Activity Outlook.

Additional information on these showers and other minor showers not included here can be found at the following sites: Wayne Hally’s and Mark Davis’s NAMN Notes, and the International Meteor Organization’s 2008 Meteor Shower Calendar.

Comets

Naked Eye Comets (V < 6.0)

None

Binocular Comets (V = 6.0 – 8.0)

None

Small Telescope Comets (V = 8.0 – 10.0)

Comet 81P/Wild 2

Comet Wild 2 is a short-period Jupiter-family comet on a 6.4 year orbit. In 1974 a close approach to Jupiter placed the comet on its current orbit which allows (relatively) close approaches to the Sun and Earth. Swiss professional astronomer Paul Wild found the comet photographically on its first close perihelion in 1978. During its last perihelion passage it was the target of the NASA Stardust spacecraft which flew through its coma, collected cometary dust, and returned the dust to Earth. Though Wild 2 has become bright enough to be seen in small backyard telescopes before, this year’s apparition will be its best since discovery. Not till 2042 will it come closer, and even then only marginally so.

This year Wild 2 will reach perihelion on February 22 at 1.60 AU and closest approach to Earth will occur on April 5 at 0.67 AU. Though the comet will only reach a brightness of magnitude ~9.2 to 9.5 in March, it will remain brighter than magnitude 10.0 from January through May.

Currently the comet is around magnitude 10.0 to 10.5 and should be around magnitude 10.0 or even brighter by the end of the month. Currently the comet is located in Virgo (not far from Saturn) at a distance of 1.64 AU from the Sun and 1.10 AU from Earth.

A finder chart for Comet Siding Spring can be found at Comet Chasing and Aktuelle Kometen (in German).

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida’s Comet Homepage.

Comet C/2007 Q3 (Siding Spring)

This long-period comet was first seen on 2007 August 25 by Donna Barton of the Siding Spring Survey in Australia. This past Oct. 7th the comet reached a rather distant perihelion at 2.25 AU from the Sun. Unfortunately, the comet and Earth are located on opposite sides of the Sun so the comet is rather far from Earth. Still the comet is observable in the early morning hours as a slowly fading ~9.5 to 10.5 magnitude comet in Bootes. At mid-month the comet is 2.52 AU from the Sun and 2.23 AU from Earth.

A finder chart for Comet Siding Spring can be found at Comet Chasing and Aktuelle Kometen (in German).

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida’s Comet Homepage.

Asteroids

Binocular and Small Telescope Asteroids (V < 9.0)

(4) Vesta

Though not as large as Ceres, Vesta is more reflective making it the brightest asteroid in the Main Belt. Vesta is peculiar in that it appears to have evidence of volcanism on its surface. Similar to the Moon, Vesta may be covered with large expanses of frozen lava flows. It is classified as a V-type asteroid and is the only large asteroid with this classification. Many of the smaller V-type asteroids are chips of Vesta blasted off it by past asteroid and comet impacts. Vesta is similar in size to Pallas with dimensions of 347x336x275 miles or 578×560×458 km. Vesta will also be visited by NASA’s Dawn spacecraft which will arrive in 2010.

Vesta is once again observable in the morning sky before the start of dawn. It is brightening from magnitude 7.1 to 6.5 as it travels to the northeast of Regulus in Leo.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Vesta from Heavens Above.

In the Sky This Month – December 2009

This feature highlights a number of meteor showers, comets and asteroids which are visible during the month of December 2009. Jupiter continues its reign as not only king of the planets but king of the evening sky. Though not visible until about 10pm or so, Mars will start to contest Jupiter’s reign this month. December also brings the Geminids which are one of the best meteor showers of the year.

Note: If anyone has pictures or observations of these objects/events and want to share them, send me a comment and I’ll post them on the blog.

Planets

Mercury - Mercury will be an evening object this month. Though not a great apparition for northern observers, it should be easy to see if you have an unobstructed view of the southwestern horizon. The best time to see Mercury will be when the Moon passes near it on during the evenings of Dec 17 and 18. At that time Mercury will be magnitude -0.5. By the end of the month, it will be rapidly fading and getting closer to the Sun.

Dec 18 - Moon within 1.3° of Mercury

Jupiter - Jupiter continues to dominate the early evening sky. At magnitude -2.2, Jupiter is ~10 times brighter than the brightest stars in the sky this month. Of all the planets, only Venus, and on very rare occasions Mars, are brighter.

Jupiter is located high in the southwestern sky by the end of dusk for easy observation. As has been the case all year, it is slowly moving through the southern constellation of Capricornus.

Dec 21 - Moon passes 4° from Jupiter
Dec 21 - Jupiter passes 0.5° from Neptune

Neptune – For those with a telescope or binoculars and a dark sky, Neptune is located within a few degrees of Jupiter. This month Jupiter and Neptune will experience the 3rd of this year’s triple conjunction as they pass ~0.5° from each other on the night of Dec 20/21. For most of the month, the 2 planets will be very close to each other and within the same field of view of most small telescopes and binoculars. This is a great opportunity to use the easy-to-find Jupiter to help locate the usually hard-to-find Neptune. Jupiter will be a bright magnitude -2.2 while Neptune will be a faint +8.0. Even Jupiter’s 4 large Galilean moons are about a dozen times brighter than Neptune even though they are much smaller. The big reason for the faintness of Neptune is its distance from both the Earth and Sun. It is roughly 6 times further away from us and the Sun as Jupiter. The distance also explains its apparent small size of 2.3″. A good sized telescope will be required to see Neptune as anything other than a faint star.

Dec 21 - Jupiter passes 0.5° from Neptune

Uranus – Uranus is located in western Pisces and is bright enough to be seen in small binoculars at magnitude +5.9 but will still require a telescope in order to see it as anything other than a star (it’s disk is only 3.5″ across).

Mars – Mars can be seen rising in the eastern sky late in the evening (~9:30 pm at the start of the month and ~8 pm at the end of the month). Mars is rapidly brightening and will double in brightness this month as it rises from +0.0 to -0.7 magnitude. By the end of the month, Mars will be brighter than all stars expect Sirius and far southern Canopus. Mars will continue to brighten to a max of magnitude -1.3 at its opposition on Jan 29 of next year. This month Mars will appear roughly stationary as it starts its retrograde motion near the Leo/Cancer border.

Dec 6 - Moon passes close (5°) to Mars

Saturn – Saturn is easy to observe during the last few hours of the night. Located in Virgo at magnitude +0.9, Virgo only rises right before the start of dawn. Telescope users should note that Saturn’s rings are still close to edge-on.

Dec 10 - Moon and Saturn within 7° of each other

Venus - Venus will be too close to the Sun this month for most observers. Some with unobstructed views of the southeastern horizon may catch a glimpse of Venus rising 30-50 minutes or so before sunrise.

Dec 15 - Venus and Moon within 3° of each other

Meteors

December hosts one of the best showers of the year in the Geminids. In addition, the background rate of meteors is still rather high. The year is usually split in 2 with January through June having low rates with few major showers while July through December (really through the 1st week of January) have high rates with many major showers.

Sporadic Meteors

Sporadic meteors are not part of any known meteor shower. They represent the background flux of meteors. Except for the few days per year when a major shower is active, most meteors that are observed are Sporadics. This is especially true for meteors observed during the evening. During December, 10 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

Geminids (GEM)

Along with the Perseids of August, the Geminids are one of the best meteor showers delivering great displays year after year. This year’s Geminids are perfectly timed as the Moon will be nearly New and will not spoil the show.

According to Sirko Molau’s analysis of video data, the Geminids are already observable at the beginning of the month though their rates are very low. The peak is predicted for the night of December 13/14 though numerous meteors should be visible for a day or two on either side of the peak. With a radiant near the star Castor in the constellation of Gemini, the Geminids are one of the rare major showers that are observable before midnight and can be observed as early as 8:00 pm though rates are usually best after 10:00 pm. Under a dark rural moon-less sky, the Geminids can produce as many as 100+ meteors per hour. Observers under suburban skies will see lower rates.

The Geminids are the result of the break-up and subsequent activity of the “asteroid” Phaethon. Why asteroid in quotes? Most meteor showers come from comets yet Phaethon is on a very non-cometary orbit and has never shown any cometary activity. There is still much scientific discussion about what exactly Phaethon is.

More details on the Geminids and their parent “asteroid” Phaethon will be posted as we get closer to its peak.

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors. Starting this month, info on most of the minor showers will be provided on a weekly basis by Robert Lunsford’s Meteor Activity Outlook.

Ursids (URS)

The Ursids will produce up to 10 meteors per hour at their peak on December 22-23. That rate makes it a borderline major/minor shower though the Ursids have experienced a number of outbursts in the past. With a radiant near the “bowl” of Ursa Minor (the “Little Dipper”), this shower is also observable all night long though the best time to observe it is during the last hours of the night.

Additional information on these showers and other minor showers not included here can be found at the following sites: Wayne Hally’s and Mark Davis’s NAMN Notes, and the International Meteor Organization’s 2008 Meteor Shower Calendar.

Comets

Naked Eye Comets (V < 6.0)

None

Binocular Comets (V = 6.0 – 8.0)

None

Small Telescope Comets (V = 8.0 – 10.0)

Comet C/2007 Q3 (Siding Spring)

This long-period was first seen on 2007 August 25 by Donna Barton of the Siding Spring Survey in Australia. This past Oct. 7th the comet reached a rather distant perihelion at 2.25 AU from the Sun. Unfortunately, the comet and Earth are located on opposite sides of the Sun so the comet is rather far from Earth. Still the comet is observable in the early morning hours as a ~9.0 to 9.5 magnitude comet in Coma Berenices. At mid-month the comet is 2.38 AU from the Sun and 2.43 AU from Earth.

A finder chart for Comet Siding Spring can be found at Comet Chasing and Aktuelle Kometen (in German).

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida’s Comet Homepage.

Comet 88P/Howell

P/Howell is an evening comet and currently the brightest in the sky. Howell is a short-period comet and takes only 5.49 years to orbit the Sun. Ellen Howell was a student at Caltech when she found the comet on photographic plates taken on 1981 August 29 with the 48″ Palomar schmidt.

In 1981 the comet was on an orbit that never brought it closer to the Sun than 1.62 AU (perihelion distance). As a result, it never got very bright. A relatively close approach to Jupiter in 1990 changed its perihelion distance to 1.40 AU. Further perturbations by Jupiter have decreased its perihelion distance to 1.36 AU. The closer perihelion distance allows the comet to get bright enough for small backyard telescopes. In addition, the comet seems to be running about ~2 magnitude brighter than usual. No obvious reason for the additional brightening has been observed yet.

This year perihelion occurred on Oct 12 so the comet is currently moving away from the Sun and should be fading. A day after perihelion I observed the comet from Tucson with a 12″ dobsonian. The comet was very difficult to observe from the city. At the time, I estimated its brightness at magnitude 8.5. The comet should be a fainter (95 mag or fainter) this month. The comet is located low in the southwest sky after dusk and will spend the monthcrossing Capricornus. At mid-month P/Howell will be 1.53 AU from the Sun and 2.02 AU from Earth.

A finder chart for Comet Howell can be found at Comet Chasing and Aktuelle Kometen (in German).

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida’s Comet Homepage.

Asteroids

Binocular and Small Telescope Asteroids (V < 9.0)

(4) Vesta

Though not as large as Ceres, Vesta is more reflective making it the brightest asteroid in the Main Belt. Vesta is peculiar in that it appears to have evidence of volcanism on its surface. Similar to the Moon, Vesta may be covered with large expanses of frozen lava flows. It is classified as a V-type asteroid and is the only large asteroid with this classification. Many of the smaller V-type asteroids are chips of Vesta blasted off it by past asteroid and comet impacts. Vesta is similar in size to Pallas with dimensions of 347x336x275 miles or 578×560×458 km. Vesta will also be visited by NASA’s Dawn spacecraft which will arrive in 2010.

Vesta is once again observable in the morning sky before the start of dawn. It is brightening from magnitude 7.7 to 7.2 as it travels just north of Regulus in Leo.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Vesta from Heavens Above.

In The Sky This Month – October 2009

This feature highlights a number of meteor showers, comets and asteroids which are visible during the month of October 2009. Jupiter continues its reign as not only king of the planets but king of the evening sky. October also brings the Orionids, one of the year’s better meteor showers.

Note: If anyone has pictures or observations of these objects/events and want to share them, send me a comment and I’ll post them on the blog.

Planets

Jupiter - Jupiter continues to dominate the evening sky. Based on the comments left on this blog, many people have been noticing Jupiter in the southeast sky during the evening. At magnitude -2.6, Jupiter is ~11 times brighter than the brightest stars in the sky this month. Of all the planets, only Venus, and on very rare occasions Mars, are brighter.

Jupiter is located high  in the southern sky by the end of dusk for easy observation. As has been the case all year, it is slowly moving through the southern constellation of Capricornus.

Oct 27 - Moon passes 3° from Jupiter

Oct_evening

View of the evening sky around 8pm on Oct 16. Sky chart made with Stellarium planetarium software.

Neptune – For those with a telescope or binoculars and a dark sky, Neptune is located within 1/2 to 3/4 degrees of Jupiter. Jupiter will be a bright magnitude -2.6 while Neptune will be a faint +7.9. That makes Jupiter over ~16,000 times brighter than Neptune. Even Jupiter’s 4 large Galilean moons are about a dozen times brighter than Neptune even though they are much smaller. The big reason for the faintness of Neptune is its distance from both the Earth and Sun. It is roughly 6 times further away from us and the Sun as Jupiter. The distance also explains its apparent small size of 2.3″. A good sized telescope will be required to see Neptune as anything other than a faint star.

Though Neptune wasn’t discovered until 1846, it was actually observed by Galileo on two occasions in 1612 and 1613. Similar to this month’s circumstances, Jupiter was passing very close to Neptune. Galileo observed and recorded Neptune as a star in the vicinity of Jupiter. There is also evidence that he noticed that Neptune had moved but didn’t follow up on it. So when you observe these 2 planets imagine what Galileo must have been thinking nearly 400 years ago.

Uranus – This month Uranus is a month past opposition and still near its maximum in brightness. Uranus is located in western Pisces and is bright enough to be seen in small binoculars at magnitude +5.7 but will still require a telescope in order to see it as anything other than a star (it’s disk is only 3.5″ across).

Mars – Mars can be seen in the eastern sky during the 2nd half of the might. It rises around midnight though it won’t get high enough to clear most trees and building till about 1-2 am. Mars is rapidly brightening from magnitude +0.9 to +0.6, its brightness matching that of many of the brightest stars visible in the morning sky. Mars will continue to brighten as it approaches its opposition on Jan 29 of next year. This month Mars marches through eastern half of the constellation of Gemini into Cancer. By Halloween, the planet will be moving through the Beehive,  a big bright star cluster in Cancer.

Oct 12 – Moon within 1.1° of Mars

Venus - Venus rises an hour before dawn. When it is visible it is easily the brightest “star” in the sky. It was at its highest in the morning sky back in August and is continuing its slow crawl lower. For binocular and telescope users, Venus will appear nearly full and is much smaller than it appeared this spring (now 11″ across versus 50″ last spring).

Oct 13 – Saturn and Venus within 0.5° of each other
Oct 16
– Moon passes 6° from Venus

Mercury - Mercury puts on its best morning show of the year for northern observers. Below the equator, this is one of Mercury’s worst displays and probably worth skipping. For the 1st 3 weeks of the month, Mercury will be visible about 30 minutes before the start of dawn in the evening sky. The dates below highlight some of the best mornings to observe Mercury.

Oct 6 – Mercury furthest above eastern horizon at dawn
Oct 8 – Saturn and Mercury within 0.3° of each
Oct 17 – Moon and Mercury within 7° of each other

Saturn – After spending the last month or so too close to the Sun to be seen, Saturn is once again visible. Located in Virgo at magnitude +1.0, Virgo only rises right before the start of dawn. For those of you lucky enough to be up every morning and have access to a clear eastern horizon, October will provide a month long show as Venus, Mercury and Saturn dance among themselves. Telescope users should note that Saturn’s rings are still close to edge-on.

Oct 8 – Saturn and Mercury within 0.3° of each
Oct 13 – Saturn and Venus within 0.5° of each other
Oct 16 – Moon and Saturn within 6° of each other

Meteors

October hosts one of the best meteor showers of the year in the Orionids. In addition, the background rate of meteors is near an annual high. The year is usually split in 2 with January through June having low rates with few major showers while July through December (really through the 1st week of January) have high rates with many major showers.

Sporadic Meteors

Sporadic meteors are not part of any known meteor shower. They represent the background flux of meteors. Except for the few days per year when a major shower is active, most meteors that are observed are Sporadics. This is especially true for meteors observed during the evening. During September, 12 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

Orionids (ORI) [Max Date = Oct 22, Max Rate = ~20-70 per hour]

The Orionids are one of the most reliable and productive showers of the year. Another point in their favor, is there high level of activity over the course of about 5 nights. This gives ample opportunity to catch a few ORI meteors.

The meteors that make up the Orionid shower were originally released by the one comet everyone has heard of, Comet Halley. Computer simulations of the past movements of Halley and its dust suggest that many of this year’s Orionid meteors were released by Halley between 1265 BC and 910 BC (for some points of reference, the Trojan War took place around 1200 BC and King David ruled around 1000 BC).

The Orionids are usually active from Oct 3 to Nov 11 with a broad peak between Oct 18 and 24. During their peak, rates can be as high as 20-70 meteors per hour. Last year rates reached 39 meteors per hour which is nearly half the rate observed in 2007 (70 per hour). With no Moon in the sky, the sky will be nice and dark this year.

The Orionids appear to come from an area in northern Orion. This area, called the radiant, rises around 10pm local time. It is best to wait till the radiant is high in the sky before looking for meteors (say 1am). The radiant is highest around 3:30am which is the best time to look. As you can see on the sky chart, the Moon is almost on top of the radiant. Meteors can appear anywhere in the sky so you don’t have to look at the radiant.

More can be found at an earlier Orionid posting.

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors. Starting this month, info on most of the minor showers will be provided on a weekly basis by Robert Lunsford’s Meteor Activity Outlook.

Comets

Naked Eye Comets (V < 6.0)

None

Binocular Comets (V = 6.0 – 8.0)

None

Small Telescope Comets (V = 8.0 – 10.0)

Comet C/2006 W3 (Christensen)

This comet was discovered nearly 3 years ago on 2006 November 18 by Eric Christensen of the Catalina Sky Survey north of Tucson. At the time the comet was located 8.7 AU from the Sun which is nearly the distance of Saturn.

The comet reached perihelion at a rather distant 3.12 AU from the Sun on 2009 July 6. Because of its large perihelion distance, the comet will only slowly move away from the Sun and, though it will slowly fade, it should remain bright enough to be seen in modest sized backyard telescopes this month.

At mid-month, the comet is 3.3 AU from the Sun and 3.2 AU from Earth. Though observed as bright as magnitude ~8.2 it is now around magnitude 8.8.  It is moving southeast while paralleling the summer Milky Way. This month the comet can be found in southern Aquila and is well placed for evening observing.

A finder chart for Comet Christensen can be found at Comet Chasing and Aktuelle Kometen (in German).

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida’s Comet Homepage.

Comet 88P/Howell

P/Howell is another evening comet and should be just as bright as C/Christensen. Howell is a short-period comet and takes only 5.49 years to orbit the Sun. Ellen Howell was a student at CalTech when she found the comet on photographic plates taken on 1981 August 29 with the 48″ Palomar schmidt.

In 1981 the comet was on a orbit that never brought it closer to the Sun than 1.62 AU (perihelion distance). As a result, it never got very bright. A relatively close approach to Jupiter in 1990 changed its perihelion distance to 1.40 AU. Further perturbations by Jupiter have decreased its perihelion distance to 1.36 AU. The closer perihelion distance allows the comet to get bright enough for small backyard telescopes.

This year the perihelion occurs on Oct 12 when it will shine at ~9.0 magnitude or maybe even a little brighter. The comet is located low in the southwest sky after dusk where it will start the month in the constellation of Scorpius before traversing Ophiuchus and ending the month in Sagittarius. At mid-month P/Howell will be 1.36 AU from the Sun and 1.65 AU from Earth.

A finder chart for Comet Howell can be found at Comet Chasing and Aktuelle Kometen (in German).

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida’s Comet Homepage.

Comet 217P/LINEAR

217P/LINEAR is also a short-period comet though it takes a little longer than Howell to circle the Sun, 7.83 years versus 5.49 years. P/LINEAR also comes closer to the Sun with perihelion at 1.22 AU from the Sun. The comet is already a month past perihelion which occurred on Sept 8.

P/LINEAR was first observed by the Lincoln Near Earth Asteroid Research (LINEAR) survey on 2001 June 21 though it wasn’t until 2001 July 11 that it was recognized as a comet. The 2009 apparition is the first return since the discovery apparition.

Though P/LINEAR and P/Howell have similar perihelion distances, LINEAR is a much fainter (or less active) comet. While Howell is ~9th magnitude at a rather distant 1.65 AU from Earth, P/LINEAR is a little fainter at magnitude ~10.0 though it is much closer (0.61 AU from Earth). This may be the last time to see P/LINEAR in small backyard telescopes until its 2048 return when it will pass within 0.40 AU of Earth. All the returns between 2009 and 2048 will be more distant.

I was able to observe 217P/LINEAR with 30×125 binoculars on the morning of Sept 25. In order to see the comet I had to drive out to a dark site. The comet was a rather non-descript smudge about 1.5′ across and with a brightness of magnitude 10.1.

This month the comet will be visible in the morning sky moving from southern Orion into the faint Milky Way constellation of Monoceros. It should remain at magnitude ~10 for the entire month.

A finder chart for Comet LINEAR can be found at Comet Chasing and Aktuelle Kometen (in German).

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida’s Comet Homepage.

Comet C/2007 Q3 (Siding Spring)

After 2 short-period comets, this next comet is of the long-period variety. Comet C/2007 Q3 (Siding Spring) was first seen on 2007 August 25 by Donna Barton of the Siding Spring Survey in Australia. This Oct. 7 the comet will reach its rather distant perihelion at 2.25 AU from the Sun. Unfortunately, the comet and Earth are located on opposite sides of the Sun (a 3.0 AU distance). Still the comet may be observable during the 2nd half of the month right before the start of dawn as a ~9.5 to 10.0 magnitude comet in Leo.

A finder chart for Comet Siding Spring can be found at Comet Chasing and Aktuelle Kometen (in German).

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida’s Comet Homepage.

Asteroids

Binocular and Small Telescope Asteroids (V < 9.0)

(3) Juno

Juno was the 3rd asteroid to be discovered after (1) Ceres and (2) Pallas. It was found by German astronomer Karl Harding on September 1, 1804. With dimensions of 320×267×200 km (192 x 160 x 120 miles) Juno ranks as the 10th largest asteroid in the Main Belt though it is the 2nd largest stony S-type asteroid.

This month it will be moving slowly southwestward in Aquarius. Peak brightness occurred at opposition on Sept. 22 when Juno was as bright as magnitude 7.6. In October it will fade from magnitude 7.8 to 8.4. Twenty degrees or so to the east of Juno is another bright asteroid, (18) Melpomene which is described in its own section.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Juno from Heavens Above.

(18) Melpomene

About 25 degrees to the east of (3) Juno lies another nice asteroid target for small telescopes. (18) Melpomene is located in the constellation of Cetus and is roughly the same brightness as Juno, peaking at magnitude 7.9 on Oct 10 and fading to magnitude  7.9 by month’s end.

Melpomene is another stoney S-type asteroid and similar to Iris was also discovered by John Russel Hind. Found in 1852, it is his 5th of 10 asteroid discoveries.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Iris from Heavens Above.

Follow

Get every new post delivered to your Inbox.

Join 104 other followers