Comets from the VATT

Last week I spent three nights observing asteroids and comet with the Vatican Observatory’s 1.8-m VATT telescope on Mount Graham in southeastern Arizona. The observing run was part of my program to characterize asteroids that could be good spacecraft targets as well as objects that are analogous to the OSIRIS-REx target asteroid. When possible I never pass up the opportunity to observe a few comets.

Though clouds affected two of the nights, the conditions were rather good. In fact, the seeing was exceptional and was as good as 0.7″ at times.

As luck would have it, the brightest comets in the sky were not visible from the VATT either because they were too far south or too close to the Sun for observation (or in the case of C/2012 K5, I just couldn’t fit it into my observing schedule).

The following is an update on a few long-period comets with some images I took from the VATT.

C/2011 L4 (PANSTARRS)

C2011L4_orbitThe big comet of the spring is supposed to be comet C/2011 L4 (Panstarrs). When discovered back in June of 2011 the brightness of the comet at a distance of ~8 AU (halfway between the distances of Jupiter and Saturn) suggested this comet could be a brilliant negative magnitude at perihelion in March of this year.

There was some questions whether this comet was on its first passage through the inner Solar System or if it had been through the neighborhood before. This is an important distinction because comets fresh from the Oort cloud have a tendency of being very active while far from the Sun. Then as the most volatile ices are sublimed off, the comet settles down into a less active state and never gets quite as bright as predicted. We have seen this many times in the past with comets being lauded as “great” or “future” comets, only to disappoint when they finally reach perihelion. Comet Cunningham in 1941, Kohoutek in 1973/74 and Austin in 1990 are prime examples

Comet PANSTARRS has an orbit that is almost indistinguishable from parabolic meaning the comet is likely to be a fresh comet from the Oort cloud. This fact had many people doubting whether it would really reach magnitude -1 as predicted by its early behavior. Now that the comet is once again observable (though only from the Southern Hemisphere) it does appear the comet’s brightening has slowed down and the comet will only reach a magnitude of +2 to +3 if that.

Recent visual observations place the comet between magnitude 7.0 and 7.5. It will continue to be a southern-only comet till mid-March when it will become visible in the early evening sky for northern observers. Sky and Telescope has some nice finder charts for the comet here. Even with a peak brightness of “only” 2nd or 3rd magnitude, the comet will be quite a sight in binoculars and small telescopes.

C/2012 F6 (Lemmon)

C2012F6_orbitIf Comet PANSTARRS is an example of the “over-hyped” comet that is “under-performing”, Comet Lemmon is the exact opposite. When discovered by the Mount Lemmon Survey last March, the comet was nothing special. Even with a perihelion distance of only 0.73 AU, the comet looked too faint to amount to much. I even placed it on my watch list for small comets that were likely to disintegrate and not survive perihelion. Instead this comet has been brightening at a much faster rate than predicted and is now the brightest comet in the sky.

Back on January 9 I spotted it in my 30×125 binoculars at magnitude 7.9. It was an easy object even though it only got ~10° above the horizon as it was speeding to the south. Its southward motion now means the comet is only visible for Southern Hemisphere observers.

The most recent visual observations place is around magnitude 6.5. If it continues like this it could rival or even surpass Comet PANSTARRS in brightness at magnitude +2 to +3 when it reaches perihelion at the end of March. For those of us up north the comet will again become visible in late April/ early May. At the time the comet will be fading but should still be around 5th magnitude.

273P/Pons-Gambart

273P_orbitThe surprise return of Pons-Gambart has been discussed in earlier posts (here, here, and here). After spending a month too close to the Sun for Earth-based observations, the comet is once again visible between magnitude 8.5 and 9.0. The comet may remain brighter than magnitude 10 and within range of small telescope users for another month or so.

Pons-Gambart has a period of ~188 years. It was seen once before in 1827 during its last perihelion passage. Its period will actually shorten by a few years results in the next return in 2191.

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C/2012 K1 (LINEAR)

C2012K1_orbitDiscovered on May 19, 2012 by the LINEAR survey at a faint 19-20th magnitude, the comet was then located at a distant 8.8 AU from the Sun. It is now ~6.8 AU out and has brightened to magnitude ~17.2. Though the comet does not look like much, it will get much brighter as it approaches its August 27, 2014 perihelion at a distance of 1.05 AU from the Sun.

Right now the comet looks on track to reach 6th magnitude at perihelion, but… similar to Comet PANSTARRS, C/2012 K1 is also an Oort cloud comet making its first visit to the inner Solar System. It is likely that it will also experience a slow down in brightening and will not get as bright as predicted. Time will tell …

In the here and now, the VATT showed K1 to be a nice small condensed comet at 17th magnitude.

C2012K1_TranSky

C/2012 S1 (ISON)

Comet ISON is the big one. Many media outlets are already calling this one the “Comet of the Century” which will shine brighter than the Full Moon. Possibly…

C2012S1_orbitAs the lesson of Comet PANSTARRS has taught us, the past behavior of a comet does not guarantee its future performance.The aforementioned Comets Cunningham and Kohoutek were also called “Comets of the Century” in their time. Neither lived up to the moniker.

ISON does have a few things going for it. The best news is its orbit which is very similar to the Great Comet of 1680. It is doubtful that ISON and the 1680 comet are one and the same. It is possible that the two comets are pieces of an older comet that split in the past. Simply being related to the 1680 comet does not mean ISON will be as spectacular as that comet but it does mean ISON has been around before and is not a new Oort cloud comet. This bodes well for ISON to brighten at a good rate and also survive perihelion.

A year ago, Comet C/2011 W3 (Lovejoy) passed even closer to the Sun than ISON will. Though Lovejoy disintegrated a few days past perihelion that was still enough time for it to produce a long bright tail that was observable for weeks (only for southern observers though, Lovejoy was invisible for Northern Hemisphere observers after perihelion). If ISON can survive it close brush with the Sun by even a few days it will produce a long bright tail that should be easily visible by northern observers (sorry southerners, ISON is our turn to enjoy a brilliant sun-grazing/skirting comet) throughout the month of December 2013.

When it reaches perihelion this November 28 (Thanksgiving Day!) it will be located only 0.012 AU from the center of the Sun or ~1.1 million km (660,000 miles) from the Sun’s surface which just under 3 times the distance from the Earth to the Moon. (Editors Note: Thanks to Joe Stieber for pointing out the error in my perihelion Sun distance!) Right now ISON is currently located at ~5 AU (the distance of Jupiter) from the Sun and still has almost 10 months to go before perihelion.

The VATT found ISON to be a nice compact 15th magnitude comet wandering among the stars of Gemini.

C2012S1_TranSky

C/2012 T5 (Bressi)

C2012T5_orbitFrom a potential great comet to an absolute runt of a comet. Comet Bressi was first spotted by Spacewatch observer Terry Bressi from Kitt Peak on October 14, 2012. If any of the comets in this blog post are likely to not survive perihelion, this is the one.

The comet is currently just within 1 AU of the Sun and little over 1 AU from Earth. Even after a recent outburst a week or two ago the comet is still rather faint. My observations place it at V magnitude 13.0 but this is most likely an underestimate as the observations were hampered by a very right Moon nearby and the comet’s low elevation. Visual observers place it closer to magnitude 11-12.

Note that unlike most comets in this blog post, Bressi is much brighter in the V versus the R. Most of the more distant comets are actually brighter in the R. The reason is that Bressi is a much more gaseous comet due to its closer distance to the Sun and perhaps even internal composition.

Comet Bressi will reach perihelion on February 24 at a distance of 0.32 AU from the Sun. It will be interesting to see if it survives. If it does it may brighten enough to be seen in small telescopes though observations will be limited to southern observers until March.

C2012T5_TranSky

C/2012 V2 (LINEAR)

C2012V2_orbitThis LINEAR comet was discovered on November 5. At perihelion on August 16, 2013 at a distance of 1.45 AU from the Sun the comet should be no brighter than 12-13th magnitude. It should remain out of reach of most visual observers.

Last week the VATT caught 2012 V2 out at a distance of ~3.1 AU from the Sun. The comet was magnitude 16 and sported a short tail extending to the northeast.

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C2012V2_TranSky

C/2012 X1 (LINEAR)

C2012X1_orbitYet another inbound Comet Linear, C/2012 X1 was first spotted last month on December 8th. It is currently at a distance of ~4.8 AU from the Sun which is just inside the distance of Jupiter’s orbit. When it reaches perihelion next year on February 21st, it will be 1.60 AU from the Sun. That’s not too close so it should only brighten to about 11th magnitude by then.

Last week the comet was seen at 18th magnitude with a broad fan tail.

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C2012X1_TranSky

C/2013 A1 (Siding Spring)

C2013A1_orbitThe first comet to be discovered in 2013 is the most recent comet to be discovered that may become bright enough for backyard observers. Rob McNaught found C/2013 A1 on January 3rd from Siding Spring, Australia. Right now the comet is further from the Sun than Jupiter is at a distance of ~7 AU. The VATT found the comet to be around V magnitude 18.7 with a nice tail to the northeast

The comet is almost 2 years from perihelion which won’t occur until October 23, 2014 at a distance of 1.39 AU from the Sun. It could become as bright as 7th magnitude at that time though a lot can happen over the next 2 years and the comet may end up significantly fainter.

C2013A1_TranSky

C/2009 P1 (Garradd)

C2009P1_orbitThe next two comets are examples of objects that were bright enough for small telescope users in the past but are now fading as they leave the inner Solar System.

Comet Garradd was a splendid sight for many months between the 2nd half of 2011 and the 1st half of 2012. During that stretch the comet was an easy binocular object of 6th-7th magnitude. Now over a year past its December 2011 perihelion (at a distance of 1.55 AU from the Sun) and 3.5 years since its discovey, the comet has retreated to a distance of 4.8 AU from the Sun which is nearly the distance of Jupiter.

My VATT images from January 20 find the comet at V magnitude 13.5. The comet displays a small condensed coma of ~1′ within a much larger diffuse coma of 3′. The bright inner coma is dust recently released by the comet while the diffuse faint outer coma is dust released when the comet was more active in the past. The fact that we are observing dust released over many months or years does make it difficult to properly measure the current activity level of the comet.

A faint broad tail can also be seen extending towards the north. Too bad the Moon was bright that night and affected the images or the tail and outer coma would have been better defined. This will be a fun comet to watch as it continues its journey back into the depths of the outer Solar System. Based on the latest orbit by Syuichi Nakano, Comet Garradd won’t be back for ~500,000 years.

C2009P1_TranSky

C/2011 UF305 (LINEAR)

C2011UF305_orbitAnother comet on the way out, C/2011 UF305 reached perihelion last July at a rather distant  2.13 AU from the Sun. Though it had a large perihelion distance it did brighten to 10th magnitude for a few months during the summer and fall of 2012.

The comet is now ~230 days past perihelion at a distance of 3 AU from the Sun. My VATT observations yield a V magnitude of ~13.8 which is still bright enough for visual observers with very large backyard telescopes to observe it. For small telescope users, the comet is well out of reach.

Drifting against the stars of Cancer, the comet was near opposition. Similar to C/2009 P1, a large diffuse dust tail can be seen extending towards the north. Most likely this is dust that was released many months ago when the comet was more active. This will also be a fun comet to see how long it can be followed as it recedes into the depth of the outer Solar System. Based on the latest orbit by Syuichi Nakano, Comet Garradd won’t be back for ~90,000 years.

C2011UF305_TranSky

In the Transient Sky – May 2012

The big event this month (at least for folks around the northern Pacific basin) is the annular solar eclipse on May 20. As for planets, Venus, Mars and Saturn are easy to see in the evening.

May 2012 Highlights
* Annular Solar Eclipse for western North America, the north Pacific basin and far eastern Asia
* Venus dominates the evening sky
* Mars fades but still is high in the evening sky
* Saturn is easily seen in eastern evening sky
* Comet C/2009 P1 (Garradd) is a nice binocular object in the evening sky

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>.

Annular Solar Eclipse

The big event this month is an annular eclipse of the Sun on May 20. For more information on when and where this event can be seen go to Science News @ NASA Science.

Planets

Evening Planets

Venus  – Venus reaches its maximum brilliance at magnitude -4.7 right at the start of the month. At the start of the month Venus is riding high in the West and sets up to 3.5 hours after the Sun. But Venus is now on a bee-line towards the Sun. By mid-month it sets 2.5 hours after the Sun and by the end of the month it will be so close to the Sun that it sets within 40 minutes of the Sun. All during the month, Venus will slightly fade but in a telescope it will appear to become bigger in apparent diameter while also becoming more crescent. All of this leads up to a rare Venus transit on June 5 when Venus will appear to pass in front of the disk of the Sun. The Moon makes a nice pair with Venus on May 22.

Mars - Mars is the bright reddish “star” nearly overhead early in the evening. Mars reached opposition (the point opposite the Sun on the sky) in early March. Since Mars was near its aphelion when we passed it on our inside track, this opposition is almost as faint as can be at a magnitude of -1.2. In May, it fades from +0.0 to +0.5. The red planet will spend the month moving eastwards below the constellation of Leo. The 1st Quarter Moon visits on the 28th.

Saturn - Saturn reached opposition on April 15 at a distance of 8.75 AU (813 million miles or 1.3 million km) from Earth. Opposition meant Saturn was directly opposite the Sun in the sky. This month it can be seen in the east at the start of evening making a nice but distant pair with bright 1st magnitude Spica. Being past opposition it will fade from magnitude +0.3 to +0.5. The nearly Full Moon visits on the mornings of the 3rd and 4th.

Morning Planets

Mercury – If you live in the Southern Hemisphere, Mercury is still in the middle of a nice morning apparition at the start of the month. By mid-month it will be too low for easy observation.  If, like me, you live north of the equator, this month’s display will be a hard one to observe. At the every end of the month, Mercury starts a better apparition for northern observers in the evening. Though still very low, It will be within ~2° of Venus although both will be only 8° from the Sun at the time.

Jupiter – With conjunction on May 13th, this planet will be located to close to the Sun to be easily seen this month.

Meteors

The year is usually split in 2 with January through June having low rates with few major showers while July through December have high rates with many major showers. Background rates will remain low in May.

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 May mornings, 6 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

Eta Aquariids (ETA)

The Eta Aquarids are a major shower, especially for southern hemisphere observers, when they peak on May 5. For northern observers, the shower will only be observable for an hour or two before dawn. Since the radiant doesn’t get very high for NH observers, rates can be low. The radiant is located near the “jar” of Aquarius.

The ETA were produced by Comet Halley which also gives us the Orionids in October. Models suggest that the ETA were released by Comet Halley no later than 837 AD. The Orionids are easy to see because the particles are hitting the Earth from the anti-solar direction. This means the meteor shower can be seen in the middle of the night. The ETA are produced by meteoroids moving outbound from the Sun, as a result the radiant is located relatively close to the Sun. This means that the ETA radiant is only visible for an hour or so before twilight. Unfortunately the Moon is full just a day after the expected peak of the ETAs on May 5 making this a difficult shower to observe this year.

The shower spans from April 19 to May 28 with a peak around May 5 with a maximum ZHR of ~60.

Additional information on these showers and other minor showers not included here can be found at the following sites: Robert Lunsford’s Meteor Activity Outlook and the International Meteor Organization’s 2012 Meteor Shower Calendar.

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors. Info on many minor showers are 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 International Meteor Organization’s 2012 Meteor Shower Calendar.

Comets

Naked Eye Comets (V < 6.0)

None this month.

Binocular Comets (V = 6.0 – 8.0)

C/2009 P1 (Garradd)

First seen way back on August 13, 2009 by Gordon Garradd who was observing for the Siding Spring Survey, a NASA-funded survey observing from Australia. At the time of discovery it was located at a distance 8.7 AU from the Sun, nearly the distance of Saturn. Perihelion occurred 2 days before Christmas 2011 at 1.55 AU from the Sun. Though the comet does not get very close to the Sun, it is an intrinsically bright comet and could have been a real sight had it come closer to the Sun and Earth.

The comet is in full retreat from the Earth and Sun as it heads outward on its long journey back to the cold depths of the outer Solar System.  Comet Garradd is slowly moving south through the constellation of Cancer in the evening sky.  Since the comet is moving away from us and the Sun it should continue to fade from around magnitude 8.0 to 8.9 as the month progresses. The comet does appear to be fading rather slowly and may be brighter than predicted here as the month progresses.

Date       RA       DEC     Delta    r    Elong   Mag
May  1   08h 50m  +38°01'   2.190  2.311    84    8.0
May 10   08h 50m  +33°56'   2.420  2.395    77    8.3
May 20   08h 52m  +30°07'   2.677  2.489    68    8.6
May 30   08h 56m  +26°51'   2.929  2.584    60    8.9

Small Telescope Comets (V = 8.0 – 10.0)

None

In the Transient Sky – April 2012

Though not quite as spectacular as March, 4 planets are visible in the evening this month (Venus, Jupiter, Mars and Saturn).

April 2012 Highlights
* Venus dominates the evening sky
* Jupiter sinks lower into the evening twilight
* Mars fades but rides higher in the evening sky
* Saturn reaches opposition on the 15th
* Comet C/2009 P1 (Garradd) is a nice binocular object in the evening sky
* Mercury is the midst of a relatively poor morning apparition for northern observers and a great apparition for southern observers  

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

Evening Planets

Jupiter – The King of the Planets continues to slowly sink into the twilight glow this month. For most of us this will be the last time to spot Jupiter in the evening sky till next year. At magnitude -2.1 to -2.0, it is still the second brightest “star” in the sky after Venus. A very thin and difficult to see Moon will pair up with Jupiter on the evening of March 22.

Venus  – Other than the Moon Venus is the brightest object in the sky. The brilliant beacon is visible high up in the southwest after sunset. Venus starts the month at its highest in the twilight sky and ends the month at its brightest (magnitude -4.7). The real showstopper occurs at the end of the apparition in June when Venus will transit the disk of the Sun. This will be the last Venus transit till 2117. The Moon and Venus make a gorgeous pair on the evening of the 24th.

Mars - Mars is the bright reddish “star” high in the East after evening twilight. Mars reached opposition the point opposite the Sun on the sky) in early March. Since Mars was near its aphelion when we passed it on our inside track, this opposition is almost as faint as can be at a magnitude of -1.2. In April, it fades from -0.7 to -0.1. The red planet will spend the month in the constellation of Leo.

Saturn - Saturn reaches opposition on April 15 at a distance of 8.75 AU (813 million miles or 1.3 million km) from Earth. Opposition means Saturn is directly opposite the Sun in the sky. As a result, it rises around sunset and is highest in the sky at midnight. The Full Moon visits on the mornings of the 7th and 8th.

Morning Planets

Mercury – If you live in the Southern Hemisphere, Mercury will put on a nice display in the morning sky reaching its highest around April 19th. If, like me, you live north of the equator, this month’s display will be a hard one to observe.

Meteors

The year is usually split in 2 with January through June having low rates with few major showers while July through December have high rates with many major showers. March marks the lowest rates of the year.

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 mornings, 10 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

Lyrids (LYR)

April brings the first major meteor shower since the Quadrantids of early January. The Lyrids were produced by Comet Thatcher, a comet on a ~400 years orbit that has only been observed once back in 1861. The Lyrids meteors, on the other hand, can be seen every year.

The radiant is located between the constellations of Lyra and Hercules. Though the radiant rises during the evening, the best time to see Lyrids is after 11 pm when the radiant is high in the sky. The shower is active from April 16 to 25 with a peak on the morning of April 22. The shower only shows good levels of activity on the night of the peak. Even then, this is the most minor of the major showers with a peak rate of ~15-25 meteors per hour.

Though there are no predictions on enhanced activity, the Lyrids have been known to put on grand displays. The 1st great display goes back almost 25oo years while the last happened in 1982. But you never know, this year the Lyrids could put on a good show.

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors. Info on many minor showers are 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 International Meteor Organization’s 2012 Meteor Shower Calendar.

Comets

Naked Eye Comets (V < 6.0)

None this month.

Binocular Comets (V = 6.0 – 8.0)

C/2009 P1 (Garradd)

First seen way back on August 13, 2009 by Gordon Garradd who was observing for the Siding Spring Survey, a NASA-funded survey observing from Australia. At the time of discovery it was located at a distance 8.7 AU from the Sun, nearly the distance of Saturn. Perihelion occurred 2 days before Christmas 2011 at 1.55 AU from the Sun. Though the comet does not get very close to the Sun, it is an intrinsically bright comet and could have been a real sight had it come closer to the Sun and Earth.

The comet is in full retreat from the Earth and Sun as it heads outward on its long journey back to the cold depths of the outer Solar System.  Comet Garradd is slowly moving south through the constellation of Cancer in the evening sky.  Since the comet is moving away from us and the Sun it should continue to fade from around magnitude 7.0 to 7.9 as the month progresses. The comet does appear to be fading rather slowly and may be brighter than predicted here as the month progresses.

Date       RA       DEC     Delta    r    Elong   Mag
Apr  1   09h 34m  +58°01'   1.517  2.047   107    7.0
Apr 10   09h 08m  +50°53'   1.693  2.124   101    7.3
Apr 20   08h 55m  +44°06'   1.919  2.212    93    7.6
Apr 30   08h 50m  +38°31'   2.165  2.302    85    7.9

Small Telescope Comets (V = 8.0 – 10.0)

None

In the Transient Sky – March 2012

Well, I guess this month’s “In the Transient Sky” is better late than never. This month is definitely the “Month of the Planets” in the evening sky. During the beginning of the month, 4 planets are visible (Mercury, Venus, Jupiter and Mars) with a 5th (Saturn) rising later in the evening.

March 2012 Highlights
* Venus and Jupiter have a spectacular conjunction in the SW
* Mars reaches opposition and peak brightness
* Comet C/2009 P1 (Garradd) is a nice circumpolar binocular object

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

Evening Planets

Mercury – Mercury starts the month near its maximum elongation in the western evening sky about ~25° to the lower right of much brighter Venus. By the 10th, the innermost planet is diving back into the Sun’s glare. Observers with a clear view of the western horizon may be able to follow Mercury till about the 12th or 13th. Next month it will begin a very poor (for Northern Hemisphere observers) morning apparition. The next Evening apparition will be in June/July.

Venus and Jupiter – Venus is the brilliant beacon in the southwest after sunset. At the end of the month (Mar 27) Venus will be at its highest in the twilight sky. It won’t be at its  brightest will the end of April (Apr 30). The real showstopper occurs at the end of the apparition in June when Venus will transit the disk of the Sun. This will be the last Venus transit till 2117. The Moon and Venus make a gorgeous pair on the evening of the 25th.

Jupiter, the King of Planets, closely shares the evening sky with Venus. By the 10th, the two are located within 4° of each other (8 lunar diameters). They close to within 3° (or 6 lunar diameters) of each other on March 13. Jupiter will continue to fall behind Venus and by month’s end the two will be ~15° apart.

The Moon makes a beautiful pairing with Jupiter on the 25th and Venus on the 26th.

Mars - After admiring Venus and Jupiter, turn around 180° and take a look for Mars, the bright reddish “star” in the East after evening twilight. Mars reached opposition the point opposite the Sun on the sky) on March 3 and is closest to Earth on March 5 at a distance of 0.674 AU or just under 63 million miles (~101 million km). Since Mars was near its aphelion when we passed it on our inside track, this opposition is almost as faint as can be at a magnitude of -1.2. The red planet will spend the rest of the month slowly fading and retrograding towards Regulus in the constellation of Leo.

Morning Planets

Saturn - Kind of the forgotten planet this month is Saturn. At magnitude +0.4 to 0.3 Saturn is located a few degrees to the lower left of the slightly fainter star Spica in Virgo (magnitude +1.0). On the 10th, the ringed planet gets high enough above the eastern horizon for easy observing by 10pm. At the end of the month, Saturn is easily seen around 9pm. The Moon visits on the morning of the 10th and 11th.

Meteors

The year is usually split in 2 with January through June having low rates with few major showers while July through December have high rates with many major showers. March marks the lowest rates of the year.

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 mornings, 10 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

None this month.

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors. Info on many minor showers are 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 International Meteor Organization’s 2012 Meteor Shower Calendar.

Comets

Naked Eye Comets (V < 6.0)

None this month.

Binocular Comets (V = 6.0 – 8.0)

C/2009 P1 (Garradd)

First seen way back on August 13, 2009 by Gordon Garradd who was observing for the Siding Spring Survey, a NASA-funded survey observing from Australia. At the time of discovery it was located at a distance 8.7 AU from the Sun, nearly the distance of Saturn. Perihelion occurred 2 days before Christmas 2011 at 1.55 AU from the Sun. Though the comet does not get very close to the Sun, it is an intrinsically bright comet and could have been a real sight had it come closer to the Sun and Earth.

The comet is in full retreat from the Earth and Sun this month as it is at the beginning of a long journey back to the cold depths of the outer Solar System. At mid-month it is 1.91 AU from the Sun and 1.30 AU from Earth and by month’s end it will be 2.04 and 1.50 AU from the Sun and Earth, respectively.

Comet Garradd is now a circumpolar object for the Northern Hemisphere meaning it never sets for those of us at Northern mid-latitudes and further north. Racing away from Ursa Minor, the comet will pass to the north and west of the Big Dipper through the “head” of Ursa Major. Since the comet is moving away from us and the Sun it should finally begin to fade from around magnitude 6.8 to 7.7 as the month progresses.

Date       RA       DEC     Delta    r    Elong   Mag
Mar  1   15h 24m  +65°59'   1.272  1.809   106    6.8
Mar 10   13h 23m  +70°35'   1.275  1.873   111    7.0
Mar 20   10h 59m  +67°32'   1.346  1.949   112    7.2
Mar 31   09h 39m  +58°51'   1.500  2.038   108    7.7

Small Telescope Comets (V = 8.0 – 10.0)

None

In the Transient Sky – February 2012

This feature highlights a number of meteor showers, comets and asteroids which are visible during the month of February 2012.

February 2012 Highlights
* Venus and Jupiter share the evening sky
* Mars brightens as it approaches opposition
* Comet C/2009 P1 (Garradd) is a nice binocular object during the morning

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

Evening Planets

Mercury – Mercury makes an evening appearance during the later half of February. Find Mercury ~30° to the lower right of Venus. The Moon will be close to Mercury on the 22nd.

Venus – Venus is the brilliant beacon in the southwest after sunset. As bright as Venus is it will only get brighter and higher in the sky for the remainder of the winter and into the spring. This year’s evening apparition is as good as it gets with peak visibility in March/April. The real showstopper occurs at the end of the apparition in June when Venus will transit the disk of the Sun. This will be the last Venus transit till 2117. The Moon and Venus make a gorgeous pair on the evening of the 25th.

Jupiter -  The King of Planets shares the evening sky with Venus. It is high in the southeast sky at the end of evening twilight. Past its late October opposition occurred it will slowly fade from magnitude -2.6 to -2.3. Located in Aries, Jupiter will appear to slowly drop lower in the sky and closer to Venus as the month progresses. On Feb 1 Jupiter and Venus are separated by 40°. This distance will shrink every night and by the end of the month they will only be 12° apart. Not that you’ll need the Moon to find Jupiter but the two will make a nice pair on the nights of the 26th and 27th.

Morning Planets

Mars - With opposition in March 2012, Mars double in brightness (magnitude -0.5 to -1.2) as it begins to retrograde near the Leo-Virgo border. Mars rises around 9 pm on the 1st and 7 pm on the 29th. The Moon pairs up with Mars on the morning of the 9th and 10th.

Saturn - Saturn rises three hours after Mars. At magnitude +0.5 Saturn will be located ~7° to the lower right of the slightly fainter star Spica in Virgo (magnitude +1.0). The Moon visits on the morning of the 12th and 13th.

Meteors

Meteor activity starts off high at the beginning of the month but then drops quickly as the month prgresses. The year is usually split in 2 with January through June having low rates with few major showers while July through December 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 mornings, 10 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

None this month.

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors. Info on many minor showers are 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 International Meteor Organization’s 2012 Meteor Shower Calendar.

Comets

Naked Eye Comets (V < 6.0)

None this month.

Binocular Comets (V = 6.0 – 8.0)

C/2009 P1 (Garradd)

First seen way back on August 13, 2009 by Gordon Garradd who was observing for the Siding Spring Survey, a NASA-funded survey observing from Australia. At the time of discovery it was located at a distance 8.7 AU from the Sun, nearly the distance of Saturn. Perihelion occured 2 days before Christmas 2011 at 1.55 AU from the Sun. Though the comet does not get very close to the Sun, it is an intrinsically bright comet and is already a borderline naked eye object for observers at very dark sites. I was able to observe the comet on the morning of January 2, 2012 with 10×50 binoculars and estimated its brightness at magnitude 6.7. The comet should only be a little brighter this month.

The comet starts the month at a distance of 1.64 AU from the Sun and 1.55 AU from Earth. At mid-month it is 1.71 AU from the Sun and 1.38 AU from Earth and by month’s end it will be 1.80 and 1.28 AU from the Sun and Earth, respectively.  Though the comet is post-perihelion and moving away from the Sun, it is also moving closer to Earth. As a result, the comet should peak in brightness this month.

Traveling north from Hercules through Draco, Comet Garradd is best in the early morning though it will be a circumpolar object by the end of the month.

Date       RA       DEC     Delta    r    Elong   Mag
Feb 1    17h 17m  +41°17'   1.548  1.642    77    6.5
Feb 15   16h 51m  +52°20'   1.377  1.714    91    6.4
Feb 29   15h 33m  +65°10'   1.275  1.802   105    6.5

Small Telescope Comets (V = 8.0 – 10.0)

None

In the Transient Sky – January 2012

This feature highlights a number of meteor showers, comets and asteroids which are visible during the month of January 2012.

January 2012 Highlights
* Venus and Jupiter share the evening sky
* Comet C/2011 W3 (Lovejoy) remains a nice, though fading, naked eye object for southern observers
* Comet C/2009 P1 (Garradd) is a nice binocular object during the morning
* Quadrantid meteor shower peaks on the 4th

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

Evening Planets

Venus – Venus is the brilliant beacon in the southwest after sunset. As bright as Venus is it will only get brighter and higher in the sky for the remainder of the winter and into the spring. This year’s evening apparition is as good as it gets with peak visibility in March/April. The real showstopper occurs at the end of the apparition in June when Venus will transit the disk of the Sun. 2012 marks the last Venus transit till 2117. The Moon pairs up with Venus on the evenings of 25th and 26th.

Jupiter -  The King of Planets shares the evening sky with Venus. It is high in the southeast sky at the end of evening twilight. Past its late October opposition occurred it will slowly fade from magnitude -2.6 to -2.3. This month it resumes moving prograde through the constellation of Aries. Not that you’ll need the Moon to find Jupiter but the two will make a nice pair on the nights of the 1st-3rd and 29th-30th.

Morning Planets

Mars - With opposition in March 2012, Mars double in brightness (magnitude +0.2 to -0.5) as it begins to retrograde near the Leo-Virgo border. Mars rises around 11 pm on the 1st and 9 pm on the 31st. The Moon pairs up with Mars on the mornings of the 12th and 13th.

Saturn - Saturn rises 3 hours after Mars. At magnitude +0.7 Saturn will be located ~6-7° to the lower right of the slightly fainter star Spica in Virgo (magnitude +1.0). The Moon visits on the morning of the 16th.

Mercury – Mercury starts off the new year at  the tail end of a rather good morning apparition. By mid-month it has sunk back into the glow of dawn.

Meteors

Meteor activity starts off high at the beginning of the month but then drops quickly as the month prgresses. The year is usually split in 2 with January through June having low rates with few major showers while July through December 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 mornings, 10 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

Quadrantids (QUA)[Max Date = Jan 4, Max ZHR = ~60-200 per hour]

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 at 7:20 UT on Jan 4 though this time could be off be 12 hours or more. Observers in Europe and the Americas will be well placed for seeing this year’s peak. Unfortunately observers south of the Equator will not see much from the Quadrantids.

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 and 2011, rates “only” reached into the 80s. The Moon will be a problem until it sets around 3 am. Then again the radiant only gets high enough for easy observing after 3 am so the Moon is not much of a problem.

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors. Info on many minor showers are 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 International Meteor Organization’s 2012 Meteor Shower Calendar.

Comets

Naked Eye Comets (V < 6.0)

C/2011 W3 (Lovejoy)

The Surprise Comet of 2011 proved the experts wrong and became the most spectacular comet since Comet C/2006 P1 (McNaught) in 2007. Terry Lovejoy is no stranger to new comets and C/2011 W3 marks his 3rd comet discovery. The Australian amateur used an 8″ telescope and CCD camera to first spot the comet on November 27. Though a diffuse relatively faint 11-12th magnitude object at discovery it was rapidly approaching the Sun. In fact, Comet Lovejoy is a member of the Kreutz sungrazing family of comets which can pass extremely close to the Sun. A small number of Kreutz sungrazers have been seen from the ground over the past 1000 years and a few have ranked as some of the best comets of all time (1106, 1843, 1880, 1882, 1887, 1965). The last Kreutz to be seen from the ground was Comet White-Ortiz-Bolelli in 1970. Since then over 2000 faint “pygmy” sungrazers have been observed close to the Sun by Sun-watching spacecraft.

Based on the apparent faintness of C/Lovejoy as it approached perihelion on December 16 at a distance of only 87,000 miles (140,000 km), it was not expected to survive long past perihelion. Surprisingly the comet did survive after showing some odd behavior near the Sun (comet appeared to fade at perihelion only to rebrighten hours later also it appeared to loss its tail until a new one formed). Due to the orientation of its orbit relative to Earth, the comet is currently only observable from the Southern Hemisphere. A number of southern observers were able to see the comet as a brilliant long tailed object of negative magnitude. Even now the tail is being reported between 20 and 40° in length. The head has rapidly faded suggesting the nucleus has either decreased greatly in activity or even broken up.

Racing away from the Sun the comet will travel across a large swatch of the southern sky this month. For northern observers we may have a chance to see what’s left of Lovejoy towards the end of the month as the comet moves north through the dim constellations of Pictor and Caelum.

Here’s Comet Lovejoy in all its glory as seen from the International Space Station and imaged by astronaut Dan Burbank.

Comet Lovejoy is visible near Earth's horizon in this nighttime image photographed by NASA astronaut Dan Burbank, Expedition 30 commander, onboard the International Space Station on Dec. 22, 2011. Credit: NASA/Dan Burbank.

Additional photos of Comet Lovejoy can be found at the sites of Seiichi Yoshida, Astronomical Society of Victoria, and Cometography (Gary Kronk).

Binocular Comets (V = 6.0 – 8.0)

C/2009 P1 (Garradd)

Until the arrival of Comet Lovejoy, Comet C/2009 P1 (Garradd) held the title of brightest comet of 2011.  First seen way back on August 13, 2009 by Gordon Garradd who was observing for the Siding Spring Survey, a NASA-funded survey observing from Australia. At the time of discovery it was located at a distance 8.7 AU from the Sun, nearly the distance of Saturn. Perihelion occured 2 days before Christmas 2011 at 1.55 AU from the Sun. Though the comet does not get very close to the Sun, it is an intrinsically bright comet and is already a borderline naked eye object for observers at very dark sites. I was able to observe the comet on the morning of January 2, 2012 with 10×50 binoculars and estimated its brightness at magnitude 6.7.

The comet starts the month at a distance of 1.56 AU from the Sun and 1.94 AU from Earth. At mid-month it is 1.58 AU from the Sun and 1.76 AU from Earth and by month’s end it will be 1.64 and 1.56 AU from the Sun and Earth, respectively.  Though the comet is post-perihelion and moving away from the Sun, it is also moving closer to Earth. As a result, the comet should brighten a little more this month.

Traveling north to the left of the ‘keyhole’ of Hercules, Comet Garradd is an early morning object this month.

Date       RA       DEC     Delta    r    Elong   Mag
Jan 1    17h 30m  +26°50'   1.936  1.555    53    6.6
Jan 16   17h 27m  +32°23'   1.762  1.584    63    6.5
Jan 30   17h 18m  +40°37'   1.561  1.638    76    6.4

Small Telescope Comets (V = 8.0 – 10.0)

None

2011 October Monthly Highlights

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

October 2011 Highlights
* Draconid meteor shower may produce high rates over Europe and Asia on the 8th
* Jupiter is at opposition on the 28th
* Comet C/2009 P1 (Garradd) is a nice binocular object during the evening
* Orionid meteor shower peaks on the 21st

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

Evening Planets

Mercury – Mercury spends the later half of the month in a poor evening apparition. Usually such a poor apparition wouldn’t be worth observing but this month Venus can be used to find Mercury. Use the Moon to find low but brilliant (magnitude -3.9) Venus and even lower and fainter (magnitude -0.3) Mercury on the evenings of October 27 and 28.

Venus – After spending the past month or so too close to the Sun to be observed, Venus is now starting its slow crawl into the evening sky. Its elongation from the Sun grows from 13° to 20° in October. Still you will need a clear view of horizon to catch Venus low in the WSW during early twilight. Use the Moon to find low but brilliant (magnitude -3.9) Venus and even lower and  fainter (magnitude -0.3) Mercury on the evenings of October 27 and 28.

Jupiter -  The King of Planets is the King of the Night Sky this month. With the other 4 naked eye planets hugging the twilight horizon or rather faint, Jupiter is by far the brightest and best placed. Rising a little over an hour after sunset on the 1st and right at sunset on the 31st, it is at its best around midnight. Opposition occurs on October 28 when Jupiter will peak in brightness at a magnitude of -2.9. For the entire month it will be slowly retrograding in the constellation of Aries. Not that you’ll need the Moon to find Jupiter but the two will make a nice pair on the nights of the 12th and 13th.

Morning Planets

Mars - With opposition in March 2012, Mars continues to slowly brighten (magnitude +1.3 to +1.1) as it moved from Cancer into Leo this month. Mars rises after midnight and is best just before dawn. If you are out watching the Orionids, Mars will be the bright ruddy star near the Moon on the mornings of the 19th and 20th.

Saturn - Saturn passes conjunction on the far side of the Sun at mid-month (Oct 13). Those with very clear eastern horizons may be able to see Saturn an hour before sunrise by the end of the month. Saturn (magnitude +0.7) will be located ~5° to the lower right of the slightly fainter star Spica (magnitude +1.0).

Meteors

Meteor activity is still near a seasonal high in October. The year is usually split in 2 with January through June having low rates with few major showers while July through December 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 October mornings, 10 or so Sporadic meteors can be observed per hour from a dark moonless sky. The Taurids should also contribute another 2-5 meteors per hour all night long.

Major Meteor Showers

Draconids (Giacobinids) (GIA) [Max Date = Oct 8, Max ZHR = highly uncertain between 50 and 600 per hour]

On October 8th at ~20 hours UT, the Draconid meteor shower may produce an outburst of meteors for observers in Europe and Asia. While normally a weak shower, the Draconids put on two of history’s best meteor storms in 1933 and 1946. In those years rates as high as 10,000 per hour were seen. More recently an outburst in 1998 produced a few hundred meteors per hour. This year the Earth will cross dust trails produced by Comet 21P/Giacobini-Zinner in 1900 and 1907, the same two trails that produced the 1933 and 1946 storms, as well as older trails back to 1866. Due to the older age and dispersion of these streams, a major storm is not possible this year. Still ZHRs as high as a few hundred per hour may be possible. The actual number of meteors seen by observers will be much less due to the nearly Full Moon. As a result, the shower may “only” appear as good as the Perseids or Geminids at their peak under a Moon-less sky.

If you’re like me and live in North America, well, we are probably out of luck. Chances are we will see little or no enhancement from the dust trail crossings. This will probably only be a good show for those in Europe, Asia and northern Africa. A map of visibility and much more information on this year’s shower cab be found at the International Meteor Organization’s (IMO) 2011 Draconids site.

Orionids (ORI) [Max Date = Oct 21, Max ZHR = ~35-45 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. This year the just past Third Quarter Moon will hamper meteor watching somewhat.

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 ZHRs reached 35-45 meteors per hour which is nearly half the rate observed in 2007 (70 per hour). This year’s activity should be similar to the last few years. With a Moon-lit sky, actual rates will be somewhat lower.

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.

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors. Info on many minor showers are 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 International Meteor Organization’s 2011 Meteor Shower Calendar.

Comets

Naked Eye Comets (V < 6.0)

None this month…

Binocular Comets (V = 6.0 – 8.0)

C/2009 P1 (Garradd)

The brightest comet of the year is long-period comet C/2009 P1 (Garradd). First seen way back on August 13, 2009 by Gordon Garradd who was observing for the Siding Spring Survey, a NASA-funded survey observing from Australia. At the time of discovery it was located at a distance 8.7 AU from the Sun, nearly the distance of Saturn. Perihelion will occur 2 days before Christmas 2011 at 1.55 AU from the Sun. Though the comet does not get very close to the Sun, it is an intrinsically bright comet and is already a borderline naked eye object for observers at very dark sites (6th magnitude).

The comet starts the month at a distance of 1.92 AU from the Sun and 1.70 AU from Earth. At mid-month it is 1.81 AU from the Sun and 1.87 AU from Earth and by month’s end it will be 1.72 and 2.01 AU from the Sun and Earth, respectively.  Visual observers are placing the comet at magnitude 6.6 to 6.8 at the end of September. It should slightly brighten this month as it slowly moves west in Hercules.

Date       RA       DEC     Delta    r    Elong   Mag
Oct 1    18h 09m  +19°23'   1.697  1.921    87    6.7
Oct 16   17h 49m  +18°51'   1.866  1.811    71    6.6
Oct 31   17h 37m  +18°44'   2.005  1.716    59    6.6

Small Telescope Comets (V = 8.0 – 10.0)

45P/Honda-Mrkos-Pajdusakova

First seen in 1948 by Japanese amateur Minora Honda, Czech astronomer Antonin Mrkos and Slovak astronomer Ludmilla Pajdusakova, this comet is on its 11th observed return since discovery (it was missed during the 1959 and 1985 returns). It is an intrinsically faint Jupiter-family comet which passes within 0.53 AU of the Sun every 5.25 years. This time perihelion passage occurred on September 28. Prior to perihelion the comet made a close approach to within 0.06 AU of Earth which was only easily visible from the Southern Hemisphere. During the next return in 2016/2017, 45P will pass within 0.08 AU of Earth on its outbound leg and will be much better placed for northern observers.

Being after perihelion, the comet will rapidly fade as it moves away from the Sun and Earth as it moves through the constellation of Leo. At the start of the month, it should still be a binocular comet at magnitude 7.6 but will be lost to binoculars within a week or so. At an elongation of 32-37° it can only be seen low on the horizon before dawn.

Date       RA       DEC     Delta    r    Elong   Mag
Oct 1    10h 26m  +08°27'   0.827  0.532    32    7.6
Oct 16   11h 17m  +05°26'   1.139  0.641    34    9.9
Oct 31   12h 03m  +01°40'   1.380  0.839    37   12.7

 

 

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