Lunar Eclipse on Sunday

[update: changed the time of mid-eclipse to 2:47 UT from 2:48 UT. thanks to Joe Stieber for catching the error. the one minute difference doesn’t change the rest of the article.]

Sunday evening will see the last of the recent tetrad of lunar eclipses for observers in the Americas. The eclipse will occur in the morning for observers in Europe, Africa, and western Asia. This eclipse has been hyped a bit more than usual due to the Moon being a ‘Super Moon’. What that means is the Moon is at the close part of its orbit to Earth and appears a little bit larger than usual. Regardless, all total lunar eclipses are worth seeing and this one will be very nice for western US observers as it will be located low on the horizons making for some nice views. Occurring during the early evening also means we don’t have to be up at weird hours of the night to see this one. This is especially convenient for showing the kids.

The Moon will enter the penumbra of Earth’s shadow at 00:12 UT though most observers will have a difficult time noticing any darkening of the Moon until around ~00:40 UT (8:40 pm EDT, 7:40 pm CDT). At that time the Moon will be below the horizon for Tucson and most observers in the Mountain and Pacific time zones.  The Moon enters the umbra of Earth’s shadow and really starts to get dark at 1:07 UT (9:07 pm EDT, 8:07 pm MDT, 7:07 pm MDT). At Tucson the Moon rises at 1:09 UT (6:09 pm PDT) only 1 minute after the start of the partial eclipse and 7 minutes before sunset. As the Moon gets higher and the sky gets darker it will become easier to see even as Earth’s shadow takes a bigger and bigger bit out of it.

The total phase of the eclipse begins at 2:11 UT (10:11 pm EDT, 9:11 pm CDT, 8:11 pm MDT, 7:11 pm PDT). The middle of the eclipse and the time when the Moon should appear darkest occurs at 2:47 UT (10:47 pm EDT, 9:47 pm CDT, 8:47 pm MDT, 7:47 pm PDT. Totality ends at 3:23 UT (11:23 pm EDT, 10:23 pm CDT, 9:23 pm MDT, 8:23 pm PDT) and the whole show should be over (meaning no obvious darkening of the Moon visible by ~5:20 UT.

Here in Tucson, the Moon will appear to rise at due east and will be observable in the southeastern sky for the entire eclipse.

2015_lunar_eclipse

View of the eastern horizon at the time of mid-eclipse for Tucson, Arizona. Chart created with Stellarium.

If you have a pair of binoculars or are taking images of the eclipse, note that two other relatively bright solar system objects are near the Moon. The planet Uranus is located ~15° to the due east or lower left of the Moon. At that time Uranus will be magnitude 5.7 (barely visible to naked eye observers from dark sites) and located 19.98 AU from the Sun and 19.02 AU from Earth (that’s 1.86 million miles from the Sun and 1.77 million miles from Earth). The Moon will be 0.0024 AU from the Earth (222,000 miles from the center of the Earth) or ~7900 times closer than Uranus. To the southeast of the Moon and about 11° away is the brightest asteroid, (4) Vesta. It will be 2.42 AU (225 million miles) from the Sun and 1.43 AU (133 million miles) from Earth or ~600 times further away than the Moon. Vesta will be a little fainter than Uranus at magnitude 6.2. Use the star chart below to find Uranus and Vesta.

2015_lunar_eclipse_vesta_uranus

Location of Uranus and asteroid Vesta relative to the eclipse Moon on Sunday evening Sep. 27. Chart created with Stellarium.

The next lunar eclipse will be on 2016 March 23 but will be a rather poor penumbral eclipse (meaning the darkest part of the shadow doesn’t cross the Moon). The next series of total lunar eclipses occur on 2018 January 31, 2018 July 27, and 2019 January 19. The first and third of this triad are visible in the US. Go to the NASA Lunar Eclipse page for more detail on these and other lunar eclipse.

Morning Sky Planets

Anyone up before dawn has probably noticed Venus shining like a brilliant beacon high in the eastern sky. For most of 2015, Venus was a bright object in the evening western sky. Last month it caught up with and passed the Earth moving roughly between the Earth and Sun. Over the past few weeks, it has moved out ahead of Earth which made it appear to rapidly climb higher and higher in the eastern morning sky.

Though not as bright as Venus, both Jupiter and Mars are also visible to the lower left of Venus. Over the next few weeks, all three planets will come into conjunction with each other [Oct 17 – Mars + Jupiter, Oct 26 – Venus + Jupiter, Nov 3 – Venus + Mars].

TransientSky_morningview_2015Sept15

Bright Stars in the Sky

Though this blog mainly focuses on comets, asteroids and meteors, the blog postings which seem to get the most hits are those referring to bright stars visible in the sky. This shouldn’t be too surprising since the most frequent (and often times most obvious) sites in the sky are bright stars low near the horizon during the hours most people are out and about (just after sunset and right before sunrise).

This post will provide a quick sweep of the early evening and early morning sky to highlight some of the brighter objects in the sky.

EVENING:

Most of the bright star action as soon as it gets dark in the evening is located in the southeastern sky. Not only do we have the usual Winter Sky suspects, but Jupiter joins them this year. Located in the middle of Gemini to the right of the pair of bright Gemini stars, Castor and Pollux, Jupiter outshines every star and planet in the evening sky. A few recent high-resolution images of Jupiter can be seen in this post.

The brightest star in the sky (though still half the  brightness of Jupiter) is Sirius. This time of the year Sirius gets a lot of attention because of its location close to the horizon near sunset. When so low Sirius may appear to not only change brightness but also to vary in color if the air is turbulent.

Night sky for northern mid-latitudes around 6:45 pm. Chart created with Stellarium. Credit: Carl Hergenrother.

Night sky for northern mid-latitudes around 6:45 pm. Chart created with Stellarium. Credit: Carl Hergenrother.

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Sirius is a blue star but can appear to change color rapidly. The reason for this is due to the Earth‘s atmosphere. Turbulence in the atmosphere causes the star’s light to be “bounced” all over the place. The light of the star is made up of many different colors which all “bounce” around differently. As a result, normally blue Sirius can appear to rapidly switch between many different colors when it is close to the horizon (meaning its light is passing through more atmosphere than usual). All stars experience this effect, it is just that Sirius‘ brightness makes it more evident. Watching Sirius when low in the sky with a telescope or just your eyes can be one of the best sights in the night sky.

Why does Sirius twinkle and change colors while brighter Jupiter does not? Check out Phil Plait’s explanation on his Bad Astronomy site.

More on Sirius can be found here.

MORNING

Some early risers may notice brilliant Venus low in the southeast. Only a few weeks ago Venus was a brilliant evening object in the southwest right after sunset. After passing roughly between the Earth and Sun, the brightest planet is now beginning a long stint as the ‘Queen of the Morning Sky’.

View of the early morning eastern sky from northern mid-latitudes around 6:35 am. Chart created with Stellarium. Credit: Carl Hergenrother.

View of the early morning eastern sky from northern mid-latitudes around 6:35 am. Chart created with Stellarium. Credit: Carl Hergenrother.

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Before leaving the morning sky, Robert Lunsford was able to image Venus through his 9.25″ telescope. At that time the planet was a very slender crescent. Venus shows a similar phase at this time as well.

Image of Venus taken by Robert Lunsford from ChulaVista, CA on 2013 January 6 with a C9.25 telescope. Credit: Robert Lunsford.

Image of Venus taken by Robert Lunsford from ChulaVista, CA on 2013 January 6 with a C9.25 telescope. Credit: Robert Lunsford.

Jupiter, all night long

The ‘King of the Planets’, Jupiter, is just days passed its January 5th opposition. Observers can easily spot it as the brightest star in the sky as it becomes visible in the northeast sky right after darkfall. By midnight, Jupiter is riding high nearly overhead. Early risers will notice the planet very low in the northwest just before the start of dawn.

Last weekend I was using at the Vatican Observatory 1.8-m VATT telescope on Mount Graham to observe comets and asteroids. For fun, I spent a little time observing Jupiter…

Jupiter from the VATT 1.8-m on January 13, 2014 UT. Note, the 'Great Red Spot' is visible. Credit: Carl Hergenrother, Vatican Observatory, University of Arizona.

Jupiter (and Ganymede) from the VATT 1.8-m on January 11, 2014 UT. Credit: Carl Hergenrother, Vatican Observatory, University of Arizona.

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Jupiter from the VATT 1.8-m on January 13, 2014 UT. Note, the 'Great Red Spot' is visible. Credit: Carl Hergenrother, Vatican Observatory, University of Arizona.

Jupiter from the VATT 1.8-m on January 13, 2014 UT. Note, Io and its shadow are in transit across the face of Jupiter. Credit: Carl Hergenrother, Vatican Observatory, University of Arizona.

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Jupiter from the VATT 1.8-m on January 13, 2014 UT. Note, the 'Great Red Spot' is visible. Credit: Carl Hergenrother, Vatican Observatory, University of Arizona.

Jupiter from the VATT 1.8-m on January 13, 2014 UT. Note, the ‘Great Red Spot’ is visible. Credit: Carl Hergenrother, Vatican Observatory, University of Arizona.

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In the Transient Sky – April 2013

April 2013 Highlights
* Comet C/2011 L4 (PANSTARRS) will be visible in the morning sky fading from magnitude 4 to 7
* Comet C/2012 F6 (Lemmon) will be a 5th-6th magnitude object for SH observers
* Saturn at opposition on the 28th
* Jupiter continues to dominate the early evening sky
* Mercury finishes a great morning apparition for southern observers (not so good for northerners)
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 was in superior conjunction last month. This month the planet is still too close to the Sun for most observers. A lucky few may be able to pick it out against the bright glow of evening twilight by the end of the month.

Jupiter – The King of the Planets dominates the early evening sky being high in the western sky at the end of evening twilight. On the 1st Jupiter sets around 11:30 pm and by 10 pm at the end of the month. It spends the month a few degrees  northeast of the stars of the Hyades cluster in Taurus as it fades from magnitude -2.1 to -2.0.  The Moon pays Jupiter a visit on the evening of the 14th.

Saturn – Saturn reaches opposition this month on the 28th. On that data the ringed planet will be observable all night long. It will also be at its brightest for the year on that night at magnitude +0.1. The Moon passes close to Saturn on the morning of the 25th.

Morning Planets

Mercury – Mercury starts the month in the midst of a good morning apparition for Southern Hemisphere observers. The view is much worse for northern observers. Mercury slowly moves back towards the Sun as the month progresses.

Mars – Both planets are too close to the Sun for easy observation this month. They will be back this summer, Venus in the evening sky and Mars in the morning sky.

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. Meteor activity is near its annual minimum this month.

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 April mornings, 5 or so Sporadic meteors can be observed per hour from a dark moonless sky. The rate is near an annual minimum this month.

Major Meteor Showers

Lyrids [LYR]

This year’s Lyrid meteor shower is seriously hampered by a nearly Full Moon on the night of its peak (April 22nd). The Moon will greatly reduce the usual number of 10-15 meteors per hour.

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 L4 (PANSTARRS)

Comet PANSTARRS peaked around magnitude 1.5 when it reached perihelion at 0.30 AU from the Sun on March 10. The comet has rapidly faded as it moves away from the Earth and Sun. Observations over the past few days place is around magnitude 4.0 to 5.0.

In March it was an evening object though it spent all month hugging the western horizon and was only visible in twilight. In April the comet can still be seen in the evening with difficulty but it has become much easier to see in the morning. PANSTARRS starts the month in Andromeda only a few degrees from the Andromeda galaxy. As the month progresses it will continue moving north across Andromeda and Cassiopeia.

The comet will fade by ~1 magnitude per week but should remain a good sight in small telescopes and binoculars all month long.

Finder charts can be found at Chasing Comets.

Ephemeris for C/2011 L4 (PANSTARRS)
Date            RA        DEC    Delta   r   Elong    V
2013 Apr 01   00m 31m  +36d 33'  1.275 0.684   32    4.4
2013 Apr 11   00h 27m  +48d 13'  1.358 0.899   41    5.5
2013 Apr 21   00h 21m  +58d 12'  1.442 1.102   50    6.3
2013 May 01   00h 11m  +67d 12'  1.528 1.295   57    7.0

RA = Right Ascension, DEC = Declination, Delta = distance from Earth in AU
r = distance from the Sun in AU, Elong = elongation from Sun in degrees
V = Visual magnitude

C/2012 F6 (Lemmon)

Everyone was expecting C/2011 L4 (PANSTARRS) and C/2012 S1 (ISON) to be the two naked eye comets of 2013. No one was expecting C/2012 F6 (Lemmon) to be vying for the status of naked eye comet when it was discovered by Alex Gibbs of the Mount Lemmon survey back on March 23, 2012. At that time the comet was a faint 20th-21st magnitude and 5.0 AU from the Sun. It also appeared to be an intrinsically faint comet. So faint in fact that I though it had a good chance of disintegrating near perihelion. Instead the comet brightened at a rapid rate.

This surprise comet brightened to magnitude 4.5 to 5.0 as it reached perihelion on March 24, 2013 at a distance of 0.73 AU from the Sun. Unfortunately there have been very few brightness estimates made over the past few weeks. Not only is the comet not visible for those north of the Equator but the comet is also located only ~24 degrees from the Sun.

Lemmon should fade now that it is moving away from the Sun and Earth and may be as faint as magnitude 6-7 by month’s end. Even though it is moving nearly due north through Cetus and Pisces this month it will still not be visible to northern observers till May.

Finder charts can be found at Chasing Comets.

Ephemeris for C/2012 F6 (Lemmon)
Date            RA        DEC    Delta   r   Elong    V
2013 Apr 01   00h 11m  -17d 50'  1.547 0.746   24    4.9
2013 Apr 11   00h 12m  -08d 40'  1.622 0.810   24    5.3
2013 Apr 21   00h 14m  +00d 06'  1.671 0.910   28    5.8
2013 May 01   00h 17m  +08d 32'  1.701 1.031   34    6.4
RA = Right Ascension, DEC = Declination, Delta = distance from Earth in AU
r = distance from the Sun in AU, Elong = elongation from Sun in degrees
V = Visual magnitude

Binocular Comets (V = 6.0 – 8.0)

None

Small Telescope Comets (V = 8.0 – 10.0)

None

In the Transient Sky – March 2013

March 2013 Highlights
* Comet C/2011 L4 (PANSTARRS) will be visible in the evening sky for northern observers at magnitude 1-2 though it will be very low on the horizon
* Comet C/2012 F6 (Lemmon) will be 4th-5th magnitude for SH observers
* Saturn rises before midnight
* Jupiter continues to dominate the evening sky
* Mercury starts a great morning apparition for southern observers (not so good for northerners)
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 dominates the evening sky being visible nearly overhead at the end of evening twilight. Jupiter is now three months past opposition. It spends the month just north of the stars of the Hyades cluster in Taurus as it fades from magnitude -2.3 to -2.1.  The Moon pays Jupiter a visit on the evening of the 17th.

Saturn – Saturn is an early morning object rising around 11:00 am at the start of the month and 9pm by the end of the month.  All month Saturn glows at magnitude +0.2 between Virgo and Libra. The Moon passes close to Saturn on the morning of the 2nd.

Morning Planets

Mercury – Mercury starts the month too close to the Sun to be seen. By the last third of the month, the innermost planet is rapidly rising out of the morning twilight glow for southern observers. Up north, the view will be much poorer.

Venus and Mars – Both planets are too close to the Sun for easy observation this month. They will be back this summer, Venus in the evening sky and Mars in the morning sky.

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. Meteor activity is near its annual minimum this month.

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 March mornings, 5 or so Sporadic meteors can be observed per hour from a dark moonless sky. The rate is near an annual minimum this month.

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)

C/2011 L4 (PANSTARRS)

Last month Comet PANSTARRS looked on pace to peak around magnitude -1 near its March 10th perihelion. But over the past few weeks the comet has not been brightening as quickly as hoped. As a result it is likely that the comet will be much fainter than -1 at its peak brightness and more along the lines of 2nd to 4th magnitude. The comet will still be a nice sight especially in binoculars and telescopes.

The comet was first seen by the Hawaiian based PanSTARRS asteroid survey on June 6, 2011 at a large distance of 7.9 AU from the Sun. At perihelion it will approach within 0.30 AU of the Sun. The comet is a new Oort cloud comet meaning it is making its first passage through the inner Solar System. The fact that it is a new Oort cloud comet explains its failure to brighten as quickly as first predicted. These sort of comet often appear relatively bright when far from the Sun because they still contain a large amount of very volatile ices. As the comet approaches the Sun, these ices sublimate and the comet brightens at a slower rate.

Even though we are only 10 days from perihelion, the comet’s peak brightness is still uncertain. The comet should be a 1st or 2nd magnitude object as it rounds the Sun near mid-month. The comet also becomes visible again from the Northern Hemisphere around that time though it will never stray far from the western horizon during evening twilight. Its low elevation and the bright evening sky will make the comet a difficult sight.

Finder charts can be found at Chasing Comets.

Ephemeris for C/2011 L4 (PANSTARRS)
Date            RA        DEC    Delta   r   Elong    V
2013 Mar 01   23h 25m  -27d 18'  1.111 0.411   21    2.5
2013 Mar 11   00h 25m  -02d 52'  1.115 0.303   15    1.4
2013 Mar 21   00h 35m  +19d 43'  1.186 0.444   21    2.9
2013 Mar 31   00h 31m  +35d 14'  1.267 0.662   31    4.5

RA = Right Ascension, DEC = Declination, Delta = distance from Earth in AU
r = distance from the Sun in AU, Elong = elongation from Sun in degrees
V = Visual magnitude

C/2012 F6 (Lemmon)

Everyone was expecting C/2011 L4 (PANSTARRS) and C/2012 S1 (ISON) to be the two naked eye comets of 2013. No one was expecting C/2012 F6 (Lemmon) to be vying for the status of naked eye comet when it was discovered by Alex Gibbs of the Mount Lemmon survey back on March 23, 2012. At that time the comet was a faint 20th-21st magnitude and 5.0 AU from the Sun. It also appeared to be an intrinsically faint comet. So faint in fact that I though it had a good chance of disintegrating near perihelion. Instead the comet brightened at a rapid rate. Perihelion will occur on March 24, 2013 at a distance of 0.73 AU from the Sun.

Over the past few days visual observers have estimated the comet at magnitude 6.2 to 6.5.

The comet is too far south for most northern observers and the comet will continue to travel the southern sky this month. As a result, this comet will only be visible to southern observers till May.

Though the comet rapidly brightened for months after discovery, its rate of brightening has slowed down markedly. Observations at the end of February place it between magnitude 5.0 and 5.5. This month the comet should brighten some more up to magnitude ~4.7.

Finder charts can be found at Chasing Comets.

Ephemeris for C/2012 F6 (Lemmon)
Date            RA        DEC    Delta   r   Elong    V
2013 Mar 01   00h 04m  -51d 22'  1.167 0.867   46    4.9
2013 Mar 11   00h 08m  -39d 10'  1.301 0.780   36    4.7
2013 Mar 21   00h 09m  -29d 31'  1.430 0.735   28    4.7
2013 Mar 31   00h 10m  -18d 46'  1.538 0.743   23    4.9
RA = Right Ascension, DEC = Declination, Delta = distance from Earth in AU
r = distance from the Sun in AU, Elong = elongation from Sun in degrees
V = Visual magnitude

Binocular Comets (V = 6.0 – 8.0)

None

Small Telescope Comets (V = 8.0 – 10.0)

C/2011 F1 (LINEAR)

No one has seen this comet for a few months because it has been too close to the Sun. Still it should have been seen by now yet it is still AWOL. Perhaps as it moves further from the glare of the Sun, it will be more easily spotted.

The LINEAR near-Earth asteroid survey picked up this comet back on March 17, 2011 at 18th magnitude. It passed perihelion on January 8 of this year at 1.82 AU from the Sun.

It is yet another comet that can only be seen from the Southern Hemisphere this month as it moves from Sagittarius to Microscopium.

Finder charts can be found at Chasing Comets.

Ephemeris for C/2011 F1 (LINEAR)
Date            RA        DEC    Delta   r   Elong    V
2013 Mar 01   21h 18m  -40d 51'  2.607 1.935   38    10?
2013 Mar 11   21h 54m  -41d 55'  2.585 1.981   43    10?
2013 Mar 21   22h 29m  -42d 39'  2.570 2.034   47    10?
2013 Mar 31   23h 05m  -43d 03'  2.561 2.092   51    10?

RA = Right Ascension, DEC = Declination, Delta = distance from Earth in AU
r = distance from the Sun in AU, Elong = elongation from Sun in degrees
V = Visual magnitude

In the Transient Sky – February 2013

February 2013 Highlights
* Not one but two comets should be naked eye brightness for SH observers (C/2011 L4 and C/2012 F6)
* Up north only comets 273P/Pons-Gambart and C/2012 T5 are bright enough for small scopes at 9th magnitude
* Comet C/2011 F1 (LINEAR) is also in range of small telescopes from the SH
* Small near-Earth asteroid 2012 DA14 passes 34,000 km from Earth on the 16th
* Mercury and Mars pass within 1/2° of each other low in the WSW evening sky on the 7th
* The Moon joins Mercury and Mars on the evenings of the 10th and 11th
* Moon occults Jupiter for observers in southern Australia
* Saturn rises before midnight
* Jupiter continues to dominate 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>.

Planets

Evening Planets

Mercury –Mercury will have three good evening apparitions for Northern Hemisphere observers this year. The first takes place this month. The innermost planet is a relatively bright -1 magnitude at the start of the month. Though it slowly fades every night it rapidly ascends higher nightly in the western sky during dusk. On the 7th it passes ~0.4° from much fainter Mars. A very thin crescent Moon is located to the lower right of the duo on the evening of the 10th and to the upper right on the 11th. By the second half of the month Mercury is fading to 1st-2nd magnitude and falling back into the twilight glow.

Mars – Use Mercury and the Moon (see above) to spot Mars this month. The red planet will be all but unobservable for most observers for the next few months as it passes behind the Sun.

Jupiter – The King of the Planets dominates the evening sky being visible nearly overhead at the end of evening twilight. Jupiter is now two months past opposition. It spends the month just north of the stars of the Hyades cluster in Taurus as it fades from magnitude -2.5 to -2.3.  The Moon pays Jupiter a visit on the evenings of the 17th and 18th.

Morning Planets

Saturn – Saturn is an early morning object rising around 1:00 am at the start of the month and 11pm by the end of the month.  All month Saturn glows at magnitude +0.5 between Virgo and Libra. The Moon passes close to Saturn on the morning of the 3rd.

Venus – Venus is too close to the Sun for easy observation this month. It will be back, this time in the evening sky, this summer.

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. Meteor activity is still near an annual maximum this month.

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 February mornings, 5 or so Sporadic meteors can be observed per hour from a dark moonless sky. The rate is near an annual minimum this month.

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)

C/2011 L4 (PANSTARRS)

Last month Comet PANSTARRS looked on pace to peak around magnitude -1 near its March 10th perihelion. But over the past few weeks the comet has not been brightening as quickly as hoped. As a result it is likely that the comet will be much fainter than -1 at its peak brightness and more along the lines of 2nd to 4th magnitude. The comet will still be a nice sight especially in binoculars and telescopes.

The comet was first seen by the Hawaiian based PanSTARRS asteroid survey on June 6, 2011 at a large distance of 7.9 AU from the Sun. At perihelion it will approach within 0.30 AU of the Sun. The comet is a new Oort cloud comet meaning it is making its first passage through the inner Solar System. The fact that it is a new Oort cloud comet explains its failure to brighten as quickly as first predicted. These sort of comet often appear relatively bright when far from the Sun because they still contain a large amount of very volatile ices. As the comet approaches the Sun, these ices sublimate and the comet brightens at a slower rate.

This month, the comet starts at a distance of 1.0 AU from the Sun with that distance dropping to 0.43 AU at the end of the month. A few recent observations place it at magnitude ~6.5-7.0. If it continues to brighten at its current rate it should become a naked eye object by mid-month. The comet will only be observable from the Southern Hemisphere this month as moves from the constellation of Sagittarius to Piscis Austrinus. Northern observers will have to wait till late March when the comet should be a naked eye object.

Finder charts can be found at Chasing Comets.

Ephemeris for C/2011 L4 (PANSTARRS)
Date            RA        DEC    Delta   r   Elong    V
2013 Feb 01   19h 21m  -45d 22'  1.649 1.009   34    6.8
2013 Feb 10   20h 26m  -45d 15'  1.427 0.822   34    6.0
2013 Feb 19   21h 49m  -41d 06'  1.238 0.626   30    4.5
2013 Feb 28   23h 16m  -29d 13'  1.118 0.431   22    3.0

RA = Right Ascension, DEC = Declination, Delta = distance from Earth in AU
r = distance from the Sun in AU, Elong = elongation from Sun in degrees
V = Visual magnitude

C/2012 F6 (Lemmon)

Everyone was expecting C/2011 L4 (PANSTARRS) and C/2012 S1 (ISON) to be the two naked eye comets of 2013. No one was expecting C/2012 F6 (Lemmon) to be vying for the status of naked eye comet when it was discovered by Alex Gibbs of the Mount Lemmon survey back on March 23, 2012. At that time the comet was a faint 20th-21st magnitude and 5.0 AU from the Sun. It also appeared to be an intrinsically faint comet. So faint in fact that I though it had a good chance of disintegrating near perihelion. Instead the comet has brightened at a rapid rate. If this brightening trend continues the comet may be a fine naked eye object this February through May. Perihelion will occur on March 24, 2013 at a distance of 0.73 AU from the Sun.

Over the past few days visual observers have estimated the comet at magnitude 6.2 to 6.5.

The comet is already too far south for most northern observers and the comet will continue to travel deeper into the southern sky this month. As a result, this comet will only be visible to southern observers till May.

The comet starts the month around magnitude 6.3 and will continue to rapidly brighten all month. By the end of the month the comet may be as bright as magnitude 6.0. It will be traveling through the far southern constellations of Musca, Octans, Tucana and Phoenix.

Finder charts can be found at Chasing Comets.

Ephemeris for C/2012 F6 (Lemmon)
Date            RA        DEC    Delta   r   Elong    V
2013 Feb 01   13h 32m  -81d 08'  0.993 1.221   76    6.3
2013 Feb 10   23h 00m  -81d 07'  0.993 1.098   67    5.5
2013 Feb 19   23h 52m  -65d 58'  1.053 0.981   57    4.5
2013 Feb 28   00h 03m  -52d 43'  1.154 0.877   47    4.0

RA = Right Ascension, DEC = Declination, Delta = distance from Earth in AU
r = distance from the Sun in AU, Elong = elongation from Sun in degrees
V = Visual magnitude

Binocular Comets (V = 6.0 – 8.0)

None

Small Telescope Comets (V = 8.0 – 10.0)

Comet C/2012 T5 (Bressi)

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.

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.

Recent observations place the comet at magnitude 10.5. If it can hold together till perihelion it should can brighten up to 8th-9th magnitude. Northern observers will only be able to follow the comet till around mid-month. After that it will solely be a southern object till next month.

Finder charts can be found at Chasing Comets.

Ephemeris for C/2012 T5 (Bressi)
Date            RA        DEC    Delta   r   Elong    V
2013 Feb 01   23h 51m  -30d 29'  1.016 0.709   41   10.5
2013 Feb 10   23h 20m  -33d 04'  0.984 0.517   30    9.8
2013 Feb 19   22h 28m  -32d 03'  0.933 0.357   21    8.9
2013 Feb 28   21h 34m  -19d 22'  0.917 0.344   20    8.0 or Puff!

RA = Right Ascension, DEC = Declination, Delta = distance from Earth in AU
r = distance from the Sun in AU, Elong = elongation from Sun in degrees
V = Visual magnitude

273P (Pons-Gambart)

On June 21, 1827, French astronomers Jean Louis Pons and Jean-Félix Adolphe Gambart discovered a comet among the stars of Cassiopeia. Both men were prolific comet finders. Pons was the most prolific discoverer of comets up until the modern era and still holds the record for most visual discoveries. A record that is unlikely to ever be broken. Between 1801 and 1827, Pons found 26 comets. Comet Pons-Gambart was his second to last comet find. Though not as prolific as Pons, Gambart is credited with 5 comet discoveries between 1822 and 1834. Comet Pons-Gambart was his 3rd find.

As the comet was already a few weeks past perihelion at discovery, it was only observed for ~1 month before it faded. Over the years, orbit computers have noticed that Pons-Gambart was on an obvious elliptical orbit and determined periods between ~45 and 65 years. The only problem was with periods that short the comet should have returned at least 2 to 4 times since 1827. Perhaps the comet was fainter now or even broke up in the intervening years to explain why it was constantly being missed.

Fast forward to this year… Robert Matson of Newport Coast, CA found evidence of an unknown comet on images taken with the SOHO spacecraft. SOHO’s SWAN imager is used to map the Lyman-α emission of the solar wind. SWAN is also very good at detecting hydrogen was dissociated water molecules released by comets. As a result, SWAN has been used to discover comets. Matson noted the presence of a comet on SWAN images from Nov. 7, 10, 11, 13 and 19. He then informed a number of observers about the new find and on Nov. 29 Terry Lovejoy of Australia found the comet.

Before the comet was even formally announed, Maik Meyer of Limburg, Germany noticed the similarities between the new SWAN/Matson comet and long-lost Comet Pons-Gambart. There is little doubt that the two are related and are probably the same object. Only problem is the 2012 observations don’t exactly match the 1827 observations assuming orbital periods of 45-65 years. A recent MPEC released by Gareth Williams of the Minor Planet Center found that the 2012 observations are consistent with a much longer period than previously assumed. It is likely that Pons-Gambart wasn’t really missed before because with a 188 year orbit this is actually its first return since 1827.

At first there was still come question as to whether the newly seen comet was Pons-Gambart and for awhile the comet was only known by its designation C/2012 V4. The Minor Planet Center has now officially announced it as 273P/Pons-Gambart.

After spending over a month too close to the Sun for observation, 273P is once again observable. This month it is a morning object traveling north from Serpens Cauda into Hercules.

Finder charts can be found at Chasing Comets.

Ephemeris for 273P/Pons-Gambart
Date            RA        DEC    Delta   r   Elong    V
2013 Feb 01   18h 30m  +05d 10'  1.636 1.132   42    9.0
2013 Feb 10   18h 22m  +10d 30'  1.538 1.243   53    9.2
2013 Feb 19   18h 10m  +16d 46'  1.432 1.359   65    9.4
2013 Feb 28   17h 54m  +24d 10'  1.331 1.477   77    9.7

RA = Right Ascension, DEC = Declination, Delta = distance from Earth in AU
r = distance from the Sun in AU, Elong = elongation from Sun in degrees
V = Visual magnitude

C/2011 F1 (LINEAR)

No one has seen this comet for a few months because it has been too close to the Sun. It should be around magnitude 9-9.5 as it slowly moves away from the Sun.

The LINEAR near-Earth asteroid survey picked up this comet back on March 17, 2011 at 18th magnitude. It passed perihelion on January 8 of this year at 1.82 AU from the Sun.

It is yet another comet that can only be seen from the Southern Hemisphere this month as it moves from Sagittarius to Microscopium.

Finder charts can be found at Chasing Comets.

Ephemeris for C/2011 F1 (LINEAR)
Date            RA        DEC    Delta   r   Elong    V
2013 Feb 01   19h 45m  -36d 01'  2.691 1.845   24    9.2
2013 Feb 10   20h 13m  -37d 51'  2.662 1.867   29    9.3
2013 Feb 19   20h 44m  -39d 26'  2.634 1.896   33    9.4
2013 Feb 28   21h 15m  -40d 44'  2.610 1.931   38    9.5

RA = Right Ascension, DEC = Declination, Delta = distance from Earth in AU
r = distance from the Sun in AU, Elong = elongation from Sun in degrees
V = Visual magnitude

Asteroids

2012 DA14

On February 15th a ~50-meter asteroid will pass 34,000 km or 21,000 miles from Earth. The asteroid will appear as a fast moving star of 8th magnitude at its closest. For observers in the United States, the asteroid will already have made its closest approach when it becomes visible. As a result it will have faded to 11th magnitude by then.

I’ll post more on this object over the next week or so.

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