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.

In the Transient Sky – January 2013

January 2013 Highlights
* Quadrantid meteor shower peaks on the morning of January 3
* Jupiter is bright in the eastern evening sky
* Jupiter and the Moon pair up on the evening of January 21
* Four comets may be brighter than 10th magnitude
* Comet C/2011 L4 (Panstarrs) approaches naked eye brightness (though it will only be visible from the southern hemisphere and will be located near the Sun)

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

Planets

Evening Planets

Mars - One needs a very clear southeast horizon to catch Mars in the early evening. Glowing at magnitude +1.2 Mars is currently not as bright as other planets. But it is traveling through a patch of sky with few bright stars so it is rather apparent as the brightest, reddest, “star” in that part of the sky. It spends most of the month against the stars of Capricornus. The Moon passes near Mars on the evening of the 12th.

Jupiter – Jupiter is now a month past opposition. It spends the month slowly retrograding just north of the stars of the Hyades cluster in Taurus as it fades from magnitude -2.7 to -2.5. It is already well up in the northeast at sundown. On the evening of January 21, the Moon and Jupiter make a beautiful pair.

Morning Planets

Saturn – Saturn is an early morning object rising around 3:00 am at the start of the month. By the end of the month, Saturn rises 2 hours earlier.  All month Saturn glows at magnitude +0.6 between Virgo and Libra. The Moon passes close to Saturn on the mornings of the 6th and 7th.

Venus – Venus is approaching its next superior conjunction (when it passes by the far side of the Sun from Earth) which takes place on March 28 and enters the evening sky. This month Venus is still a morning object though it can only be seen within an hour of sunrise. On the morning of January 10th, a very thin crescent Moon is located near Venus. This will be the last month to easily see Venus until the Summer when it will reappear in the western Evening sky.

Mercury – Mercury is too close to the Sun for easy observation this month. It will be observable next month in the evening 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 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 early January mornings, 10 or so Sporadic meteors can be observed per hour from a dark moonless sky. The rate drops as the month progresses.

Major Meteor Showers

Quadrantids (QUA) [Max Date = January 3, Max ZHR = ~60+ per hour]

This year’s Quadrantids will peak during the morning of January 3rd. Unfortunately, a very bright Moon will be located high in the southern sky during the prime morning meteor watching hours.

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 13:30 UT on Jan 3 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, 2011 and 2012, rates “only” reached into the 80s. The waning gibbous Moon will be a problem as it rises around 10:45 pm and is up for the rest of the night. With the radiant only getting high enough for easy observing after 3 am the Moon will be a hindrance. Meteor watchers should try to look at a part of the sky that does not include the Moon in your field-of-view.

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)

This comet is forecast to reach a brilliant magnitude ~-1 near its March 10th perihelion. At the time the comet only be 0.30 AU from the Sun. As bright as this is, the comet will be poorly situated close to the horizon. Still it will be a very nice binocular or small telescope sight. 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.

This month, the comet starts at a distance of 1.6 from the Sun though that distance will drop to 1.0 AU at the end of the month. A few recent observations place it at magnitude ~8.3. If it continues to brighten as expected it may even break 6th magnitude by the end of the month. The comet will only be observable from the Southern Hemisphere this month as it slowly moves away from the Sun against the stars of Scorpius and Corona Australis. 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
2012 Jan 01   17h 17m  -39d 17'  2.427 1.589   24    8.3
2012 Jan 11   17h 46m  -41d 23'  2.185 1.412   29    7.6
2012 Jan 21   18h 23m  -43d 31'  1.932 1.226   32    6.7
2012 Jan 31   19h 14m  -45d 15'  1.674 1.030   34    5.6

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)

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 faint 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 ~8.5. I was able to observe the comet on Christmas morning at magnitude 9.6. Since there was cirrus around my estimate is probably an underestimate. The comet was rather big (6′ across) and diffuse with no sign of a tail in my 30×125 binoculars.

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 8.5 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 south from Hydra through Centaurus, Crux, and Musca.

Finder charts can be found at Chasing Comets.

C2012F6_2012Dec20

Ephemeris for C/2012 F6 (Lemmon)
Date            RA        DEC    Delta   r   Elong    V
2012 Jan 01   12h 08m  -36d 30'  1.453 1.660   83    8.6
2012 Jan 11   12h 18m  -47d 42'  1.243 1.518   85    7.8
2012 Jan 21   12h 33m  -62d 08'  1.084 1.376   83    7.0
2012 Jan 31   13h 19m  -79d 22'  0.997 1.235   77    6.2

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

Small Telescope Comets (V = 8.0 – 10.0)

C/2012 K5 (LINEAR)

This is a long-period comet discovered by the LINEAR near-Earth asteroid survey program on May 25, 2012. At the time the comet was around magnitude 17-18. Though it passed through perihelion on Nov. 28 at a distance of 1.14 AU, the comet reached its brightest last month as it rapidly approached Earth. Close approach occurred at the very end of December at a distance of 0.29 AU (27 million miles or 44 million km).

Recent visual observations place the comet around magnitude ~8.6 at the end of December. Since the comet is now moving away from the Earth and Sun this month, it should rapidly fade to magnitude ~11.4 by the end of the month. The comet is now an evening object as it moves from Auriga through Taurus into Eridanus.

I imaged the comet back on Oct. 21 with the University of Arizona’s Kuiper 1.5-m telescope. Though still over a month from perihelion and located low in the sky, the comet displayed an impressive tail and even some near-nucleus jet activity.

Finder charts can be found at Chasing Comets.

C2012K5_2012Nov21

Ephemeris for C/2012 K5 (LINEAR)
Date            RA        DEC    Delta   r   Elong    V
2012 Jan 01   06h 25m  +45d 45'  0.294 1.259  157    8.5
2012 Jan 11   04h 40m  +10d 17'  0.428 1.333  138    9.4
2012 Jan 21   04h 13m  -04d 25'  0.673 1.418  116   10.6
2012 Jan 31   04h 04m  -10d 35'  0.942 1.512  103   11.4

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

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.

The comet has been too close to the Sun to be seen since early December. By the end of the January, the comet will be far enough from the Sun to once again be seen by visual observers as it moved through the stars of Serpens Cauda. How bright it will be at the time is still uncertain though the comet could still be brighter than magnitude 9.

Finder charts can be found at Chasing Comets.

Ephemeris for 273P/Pons-Gambart
Date            RA        DEC    Delta   r   Elong    V
2012 Jan 01   18h 51m  -09d 54'  1.770 0.843   13    8.2
2012 Jan 11   18h 45m  -05d 14'  1.773 0.911   19    8.4
2012 Jan 21   18h 38m  -00d 30'  1.728 1.007   30    8.7
2012 Jan 31   18h 31m  +04d 37'  1.646 1.120   41    9.0

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

In the Transient Sky – December 2012

December 2012 Highlights
* Geminid meteor shower peaks on the night of December 14/15
* Jupiter bright in the eastern evening sky
* Jupiter and the Moon make a spectacular Christmas pair
* Comet C/2012 K5 (LINEAR) brightens to 8th magnitude

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

Mars - One needs a very clear southeast horizon to catch Mars in the early evening. Glowing at magnitude +1.2 Mars is currently not as bright as other planets. But it is traveling through a patch of sky with few bright stars so it is rather apparent as the brightest, reddest, “star” in that part of the sky. It spends most of the month against the stars of eastern Sagittarius before approaching Capricornus at the end of the month. The Moon passes near Mars on the evening of the 14th.

Jupiter – Jupiter reaches opposition on December 2nd. At that time it is at its brightest (magnitude -2.7) and closest to Earth (4.07 AU). It spends the month slowly retrograding just north of the stars of the Hyades cluster in Taurus. At the start of the month it rises in the northeast at sundown. By the end of the month, it is well up in the eastern sky by nightfall. On Christmas night, the Moon and Jupiter will make a beautiful pair.

Morning Planets

Saturn – Saturn is an early morning object rising around 4:30-5:00 am at the start of the month. By the end of the month, Saturn rises 2 hours earlier.  All month Saturn glows at magnitude +1.3. The Moon passes close to Saturn on the mornings of the 10th.

Venus – Venus rises around 5:00 am on the 1st and 6:00 am on the 31st. In a telescope the planet will appear more than half-illuminated (about 90%). At magnitude -3.8, Venus is by far the brightest ‘star’ in the morning sky.  The Moon passes to the south of Venus on the morning of the 11th. Venus will become more and more difficult to observe over the coming months as it approaches conjunction with the Sun.

Mercury – Mercury is the last of the morning planets to rise. On the 1st it is magnitude -0.2 and rises around 5:30 – 6:00 am. It is still observable peaking above the southeast horizon just before day break through the middle of the 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. 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 December mornings, 10 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

Geminids (GEM) [Max Date = Dec. 13, Max ZHR = ~120 per hour]

The night of December 13/14 will bring the peak the Geminids, one of the year’s better meteor showers. It’s usually a toss up as to which is better, the Perseids of August or the Geminids, though lately the Geminids have been routinely out-producing the Perseids. If the sky is clear it will provide one of the few nights of the year when it’s almost guaranteed that you will be able to observe a meteor after about 10-20 minutes of observing.

From a dark, moon-less sky, the Geminids have been known to consistently produce rates of over 100 meteors per hour at their peak. Unlike most showers that can only be observed in the early hours of the morning, the Geminids can be seen in good numbers as early as 10 pm and are great anytime after midnight. The Geminids will appear to radiate from the constellation of Gemini near the bright star Castor.

According to analysis of meteor video data by Sirko Molau, the Geminids are active for almost an entire month between the dates of November 23 and December 21. Though high rates are only possible within a few days of the peak.

The International Meteor Organization (IMO) has a “live” graph showing the rate of the Geminids as reported by visual observers around the world.

Most meteor showers are produced by comets with orbits that extend out to the orbit of Jupiter or beyond. The Geminids are different. They are on a very short uncomet-like orbit that extends from a very close 0.14 AU from the Sun to a not so far 2.40 AU.

1) Phaethon could be a comet whose original orbit evolved into its current one after many millennia of close approaches with the inner planets. Some models of the formation of the Geminids require the shower particles to be released over many centuries to millennia. This is consistent with the behavior of a comet.

2) Phaethon may be a Main-Belt comet. Main-Belt comets are objects that originate in the outer Asteroid, or Main, Belt. Since they contain a sizable fraction of volatile material (water, carbon monoxide, etc.), they can occasionally exhibit cometary activity. Four of these objects have been observed to display cometary activity in the Main Belt. Since they start on asteroid orbits, it is not too difficult for one of them to find itself on an orbit similar to Phaethon.

3) Phaethon is an asteroid that broke up in the past. There is evidence to suggest that Phaethon is just the largest piece of a past break-up. In fact, two additional asteroids that may once have been a part of Phaethon have been found, (155140) 2005 UD and 1999 YC. According to Peter Jennisken’s book “Meteor Showers and Their Parent Comets”, the Geminids can be explained by the break-up of Phaethon just after perihelion many orbits ago. Since Phaethon gets to within 0.14 AU (14% of the Earth-Sun distance), perhaps it split under the intense solar heat. BTW, this scenario does not rule out Phaethon as a ice-rich Main-Belt comet.

The recent discovery of additional asteroids related to Phaethon points to scenario 3 as the most likely origin of the Geminids. If true, the Geminids were not the result of long-term cometary activity like most meteor showers but were created in a single event when Phaethon split or shed a smaller piece. The Daytime Sextentids and perhaps the very minor Canis Minorids were created by even older break-up events.

The video below contains 159 meteors detected by my SALSA3 camera during the 2010 Geminids peak over Tucson. It starts in the evening where you can catch a short glimpse of the Moon as it quickly moves out of the frame. Note the top of one of my trees illuminated by Christmas lights for the first few meteors. Though not all of the meteors are Geminids most are and it is fun to watch them radiate from the twin stars of Castor and Pollux.

GEMS

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)

None this month

Small Telescope Comets (V = 8.0 – 10.0)

C/2012 K5 (LINEAR)

This is a long-period comet discovered by the LINEAR near-Earth asteroid survey program on May 25, 2012. At the time the comet was around magnitude 17-18. Though it passed through perihelion on Nov. 28 at a distance of 1.14 AU, the comet will become brighter this month as it rapidly approaches the Earth. Close approach will occur at the very end of December at a distance of 0.29 AU (27 million miles or 44 million km).

Recent visual observations place the comet around magnitude 10.0 at the end of November. The comet should brighten by another 2 magnitudes by the end of December. This month it is primarily a northern hemisphere object and spends much of the month running the length of the Big Dipper from the handle to the bowl before rocketing southward through the rest of Ursa Major into Lynx. The fact that it spends the first 3 weeks of the month among the familiar stars of the Big Dipper should aid many people in seeing the comet.

The comet starts the month as a small telescope object but by the middle of the month it should be visible in binoculars for observers under a dark sky. For bright sky observers a small telescope may still be needed.

I did observe the comet back on Oct. 21 with the University of Arizona’s Kuiper 1.5-m telescope. Though still over a month from perihelion and located low in the sky, the comet displayed an impressive tail and even some near-nucleus jet activity.

C2012K5_2012Nov21

Ephemeris for C/2012 K5 (LINEAR)
Date            RA        DEC    Delta   r   Elong    V
2012 Dec 01   14h 03m  +45d 41'  0.881 1.142   75    9.9
2012 Dec 11   13h 33m  +50d 48'  0.643 1.158   88    9.3
2012 Dec 21   11h 53m  +60d 05'  0.418 1.196  110    8.7
2012 Dec 31   06h 48m  +49d 48'  0.294 1.253  153    8.0

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

In the Transient Sky – November 2012

November 2012 Highlights
* Leonid meteor shower peaks on the morning of November 17 though rates will be low
* Jupiter and the Moon pair up on the evenings of the 1st and 28th
* Venus and Saturn pair up on the morning of the 26th-27th
* Venus, Mercury and Saturn are all visible in a line at the end of the month

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 very low in the southwest after dusk. It is probably too low for most observers. Luckily it appears in the morning at the end of the month.

Mars - Mars glows at a rather meager +1.2 magnitude this month low in the southwest after dusk. It is only visible for anout an hour after sunset as it continues its slow descent towards the horizon. Use the Moon to find Mars on the evenings of the 15th and 16th.

Jupiter – Jupiter is heading towards its December 2nd opposition. At the start of the month it rises in the northeast around 7:30 to 8:00 pm. On the evening of the first, it makes a spectacular pair with the Moon between the horns of Taurus. The two pair up again on the evening of the 28th. At magnitude -2.6 to -2.7 it is the brightest “star” in the sky with the exception of early morning Venus.

Morning Planets

Venus – Venus rises about 2 hours before the Sun this month. In a telescope the planet will appear more than half-illuminated (about 80%). At magnitude – 4.1, Venus is by far the brightest ‘star’ in the morning sky. This November Venus makes a close pairing with the star Theta Virginis on the 12th and 13th, a more distant pairing with 1st magnitude Spica on the 17th and a rather close pairing with Saturn on the 26th and 27th. The Moon also passes to the south of Venus on the morning of the 11th. During the last week of November, Venus, Saturn and Mercury

Saturn – Saturn is an early morning object. Venus passes very close to Saturn on the mornings of the 26th and 27th.

Mercury – The innermost planet pops above the southeast horizon just before dawn during the last week of the month. It is the lower left planet in a line made up of Saturn-Venus-Mercury.

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

Major Meteor Showers

Leonids (LEO) [Max Date = Nov. 17, Max ZHR = ~10-15 per hour]

The Leonids are the result of dust released by Comet Tempel-Tuttle. The comet resides on an orbit that spans from just inside the orbit of the Earth (0.98 AU) to slightly beyond the orbit of Uranus (19.7 AU). It takes the comet ~33 years to orbit the Sun. The the comet last passed perihelion (closest distance to the Sun) in 1998 and was well observed at that time.

The first recorded appearance of the Leonids was in 902 AD when the shower was seen from Italy and Egypt. For the next few centuries, impressive Leonid displays were observed every 33 to 200 years or so.

Two Leonid storms stand out from all the others. On 1833 November 13, the entire eastern United States was awaken to a sight very few had every seen. The sky appeared to be filled with meteors. Modern researchers now know the cause of this outburst. It is estimated that a rate of up to ~70,000 meteors per hour was observed. That works out to ~20 meteor per second.

The 1833 storm marks the dawning of the modern age of meteor science. It was due to observations of this storm that astronomers first recognized that meteors originate in space. About 30 years later, after the discovery of Comets Swift-Tuttle (parent of the Perseids) and Tempel-Tuttle (the parent of the Leonids), the connection between comets and meteor showers was made.

The 1833 storm ranks as one of the 2 best meteor displays in recorded history. 133 years after the 1833 storm, the Leonids once again set the skies ablaze. On the night of 1966 November 17, the western United States experienced a storm just as strong as the 1833 storm.

When the comet returned in 1998, there were many predictions for spectacular Leonid activity. Though meteor rates never got close to that seen in 1833 or 1966, rates as high as a few thousand meteors per hour were observed in multiple years. The best meteor shower I have ever seen was the 1998 Leonid fireball display. Though I would observe Leonid displays with much higher rates of meteors, the sheer number of extremely bright meteors in 1998 was breathtaking.

Unfortunately no major display is forecast for 2012. Rather rates should be a meager 10-15 per hour for observers under dark skies.

 

The Leonids appear to come from an area in the “sickle” of Leo. This area, called the radiant, rises around midnight local time. It is best to wait till the radiant is high in the sky before looking for meteors (say 2am). The radiant is highest around the start of dawn. 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 2012 Meteor Shower Calendar.

Comets

Naked Eye Comets (V < 6.0)

None this month.

Binocular Comets (V = 6.0 – 8.0)

None this month

Small Telescope Comets (V = 8.0 – 10.0)

168P/Hergenrother

The surprise comet of the year, little 168P was only expected to brighten to magnitude 15 or so this apparition even though it passed within 0.42 AU of the Earth and 1.41 AU of the Sun in late October/early November. A number of outbursts and splitting events resulted in 168P brightening up to 9th magnitude. Recent large telescope observations have detected a secondary nucleus which split off from the main nucleus during on of the outbursts.

As of the 1st of the month, 168P is probably a little fainter than 10th magnitude as it slowly fades after its last outburst. Hopefully another outburst will occur and push the comet back into the realm of small telescope observation.

In the Transient Sky – October 2012

October 2012 Highlights
* Orionid meteor shower peaks on the night of October 20-21
* Venus and Regulus pair up on the morning of the 3rd
* Mars and Antares pair up on the evening of the 20th

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 – For northern hemisphere observers, Mercury spends the month in a very poor evening apparition. The best time to try and spot Mercury will be on the 16th when a very young, day old Moon is just to the lower right of Mercury. South of the equator, the show is much better as this is one of Mercury’s best evening apparitions of the year.

Mars - Continuing its slow descent towards the Sun in the evening, Mars glows at a rather meager +1.2 magnitude. On the 20th and for a few days on either side of that date, Mars pairs up with its nemesis, Antares (in ancient Greek, ‘the anti-Mars’). Antares is just a bit brighter than Mars at magnitude +1.1 and both objects are red. You can spot the two low in the SW at the end of evening twilight. The Moon joins the show on the evenings of the 17th and 18th.

Morning Planets

Jupiter – Jupiter rises around 10-11 pm at the start of the month and around 8-9 pm at the end of the month. Still it is considered a morning object because it reaches its highest point in the sky after midnight. Shining between magnitude -2.5 to -2.7, it is the brightest object in the night sky after the Moon and Venus. This month Jupiter is slowly traveling among the picturesque stars of the winter Milky Way constellation of Taurus as it heads towards opposition on December 3rd. The Moon passes nearby on the nights of Oct. 5th and 6th.

Venus – Venus rises about 3.5 hours before the Sun this month. In a telescope the planet will appear more than half-illuminated (about 70-80%). At magnitude – 4.1, Venus is by far the brightest ‘star’ in the morning sky. October sees Venus make a tight pair (0.2°) with Regulus, the brightest star in Leo, on the 3rd. The Moon also passes to the south of Venus on the morning of the 12th.

Saturn – The ringed planet is too 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. Meteor activity is at an annual peak 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 October mornings, 10 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

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 waxing Moon will set before midnight making for nice dark skies during the prime Orionid-watching early morning hours.

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.

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. 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 2012 Meteor Shower Calendar.

Comets

Naked Eye Comets (V < 6.0)

None this month.

Binocular Comets (V = 6.0 – 8.0)

None this month

Small Telescope Comets (V = 8.0 – 10.0)

None this month

In the Transient Sky – August 2012

August 2012 Highlights
* Perseid meteor shower peaks on the morning of August 12
* Moon occults Venus on August 13
* Moon located between Venus and Jupiter during the peak of the Perseids
* Mars, Saturn and Spica form a tight group mid-month (Moon joins on the 21st)
* Mercury is visible in the morning after mid-month

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

Mars and Saturn - Mars and Saturn are visible in the WSW sky during early evening hours. The two are joined by the bright 1st magnitude star Spica. The three are similar in brightness with the brightest being Saturn at magnitude +0.8 followed by Spica at magnitude +1.0 and Mars at +1.1 to 1.2. Saturn moves slowly relative to the stars and will be within 5° of Spica all month. Mars is moving much faster. At the start of the month Mars is ~7° of Saturn and Spica. On the 13th and 14th Mars passes in between Saturn and Spica. The three will form a nice line only ~5° long on those evenings. The Moon joins to make a quartet on the evening of the 21st.

Morning Planets

Jupiter – The largest planet rises around 1-2 am at the start of the month and around 11 to midnight at the end of the month. At magnitude -2.2 to -2.3 it is much brighter than the evening planets. Jupiter is currently moving slowly through the constellation of Taurus. The Moon is nearby on the mornings of August 11 and 12 (the night before and the night of the Perseid peak).

Venus – Venus rises about 3.5 hours before the Sun this month. In fact, on August 15 it is at Greatest Elongation from the Sun. In a telescope the planet will appear half-illuminated. The Moon is close by on the mornings of August 13th and 14th. The Moon passes so close to Venus that it actually passes in front of the planet for all of Mexico and the United States and all but the extreme NE corner of Canada. The event can also be seen from Japan, the Koreas, NE China and eastern Siberia. In the United States, the occultation is visible during the late afternoon on August 13. The Moon and Venus will be very low in the sky for eastern observers. The view is easier towards the western half of the country.

Mercury – The innermost planet is too close to the Sun for easy observation at the beginning of the month. By 2nd week of August it is rapidly climbing out of the dawn twilight. Use the Moon to spot Mercury on the morning of the 15th (Mercury to the lower left of the Moon) and 16th (Mercury above a very thin crescent Moon).

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 at an annual peak 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 June mornings, 7 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

Perseids (PER)

The Perseids are one of the 2 annual showers worth getting up early for. This year the peak will occur on the morning of August 12. The Moon will be up at that time though it shouldn’t hamper meteor watching too much.

From the International Meteor Organization’s 2012 Meteor Calendar:

Recent IMO observations found the timing of the mean or “traditional” broad maximum varied between λ⊙ ∼ 139.8° to 140.3°, equivalent to 2012 August 12, 07h to 19h30m UT. No additional peaks are anticipated this year, but this does not guarantee what will occur!

Although the Moon is a waning crescent, three days after last quarter on August 12, it will rise from mid-northern locations around local midnight to one a.m. Its brightness and relative proximity to the Perseid radiant should be considered more of a nuisance than a deterrent, even so. Such mid-northern latitudes are the more favored for Perseid observing, as from here, the shower’s radiant is usefully observable from 22h—23h local time onwards, gaining altitude throughout the night. The near-nodal part of the “traditional” maximum interval would be best-viewed from eastern Asia east to far western North America (with increasing moonlight for places further east in this zone), assuming it happens as expected. All forms of observing can be carried out on the shower, though unfortunately, it cannot be usefully observed from most of the southern hemisphere.

The best time to look will be after about 1-2 am on the night of August 11/12. Meteors will appear to radiate from the constellation of Perseus in the northeast sky.

Over the past five years, the Perseids have peaked with zenithal hourly rates (ZHR) of 58 (in 2011), 91 (in 2010), 173 (in 2009), 116 (in 2008) and 93 (in 2007). These are the rates that would be seen under perfectly dark skies, with no Moon and with the radiant overhead. In reality these conditions are never really met especially if you live anywhere near a city. Still observed rates of 20-40 meteors per hour are possible even under suburban skies.

The Perseids were produced by Comet 109P/Swift-Tuttle which orbits the Sun once ever ~135 years. This comet was discovered by American astronomers Lewis Swift (Marathon, New York) and Horace Tuttle (Cambridge, Massachusetts) in July of 1861. During that return the comet reached a bright 2nd magnitude and developed a tail up to 30° long. The comet returned late in 1992 and brightened up to 4th-5th magnitude. Based on our updated knowledge of Swift-Tuttle’s orbit it is now known that the comet was also seen in 1737 and likely seen in 188 AD and 69 BC.

Back in 1992, Tim Spahr and I used the Catalina schmidt to take a photographic image of Comet Swift-Tuttle (seen below).

Comet Swift-Tuttle observed with the University of Arizona Catalina Schmidt in 1992. This is a scan of a photographic image taken by Tim Spahr and Carl Hergenrother. Credit: Carl Hergenrother/Tim Spahr.

The best time to look will be after about 1-2 am on the night of August 12/13. Meteors will appear to radiate from the constellation of Perseus in the northeast sky.

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)

None this month

Small Telescope Comets (V = 8.0 – 10.0)

None this month

In the Transient Sky – June 2012

July 2012 Highlights
* Venus and Jupiter share the early morning sky
* The Moon, Venus, Jupiter and Aldebaran are within 5° of each other on the morning of the 15th
* Mars and Saturn slowly fade in the evening sky
* Mercury continues a nice apparition 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>.

Planets

Evening Planets

Mercury – This month Mercury finishes off a rather good evening apparition for northern observers. On the 1st Mercury is located a few degrees above the WNW horizon an hour after sunset. It will quickly drop (as well as slowly fade) out of sight by the 2nd week of July.

Mars - Mars is the brightish reddish “star” to the SW early in the evening. Mars reached opposition (the point opposite the Sun on the sky) in early March. In July, it fades from magnitude +0.9 to +1.1. The red planet will spend the month moving eastwards through western Virgo. The Moon visits on the evenings of the 23rd and 24th.

Saturn - Saturn reached opposition on April 15 at a distance of 8.75 AU (813 million miles or 1.3 million km) from Earth. This month it continues making a nice but distant pair (~5°) with the bright 1st magnitude Spica. Both can be seen to the South at the end of twilight. Saturn will fade from magnitude +0.7 to +0.8. The Moon visits on the mornings of the 24th and 25th. Mars is quickly closing in on Saturn and Spica and will make a nice trio of similarly bright “star” in mid-August.

Morning Planets

Jupiter and Venus – Last March, these two put on a nice display in the evening sky. After parting for a few month, they are back together, this time in the early morning sky. On the 1st, the two are located within ~5° of each other. Jupiter is further from the horizon at magnitude -2.0. Venus is much brighter at magnitude -4.6 and further down. About 3° below Venus is the brightest star in Taurus, 1st magnitude Aldebaran. Both planets will shift down relative to the stars with Venus passing within 1° of Aldebaran on the morning of the 9th. On the morning of the 15th the Moon will join the two planets and Aldebaran. All 4 will be located within an area 7° across. Definitely wake up early to see this.

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 really takes off 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 June mornings, 7 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

Southern Delta Aquariids

This shower will be spoiled by the nearly Full Moon this year. Luckily the even better Perseids in August won’t be bothered by the Moon.

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)

None

Small Telescope Comets (V = 8.0 – 10.0)

Comet 96P/Machholz

Comet 96P/Machholz is the only comet that will be brighter than 10th magnitude this month. And even it will be a difficult object as it will be located very close to the Sun.

This comet was discovered the old fashioned way, by an astronomer looking through a telescope. No cameras, whether photographic or digital, were used. Don Machholz first spotted 96P on 1986 May 12 from Loma Prieta peak in California. It currently takes ~5.3 years to orbit the Sun.

It has one of the smallest perihelion distances of any short-period comet at 0.12 AU. For this go-around, the comet will reach perihelion on July 14. Though the comet will be very bright at perihelion, estimates range from magnitude +2 to -2, it will be located within a few degrees of the Sun at that time making it invisible to everyone except for a few Sun-watching spacecraft. With difficulty, observers with telescopes in the Southern hemisphere will be able to watch the comet rapidly brighten but also rapidly approach the Sun for the first few days of July. Those of us in the Northern hemisphere have a chance of spying the quickly fading comet during the last few nights of July.

Date            RA        DEC    Delta   r   Elong    V
2012 Jul 01   05h 35m  -02d 44'  0.955 0.521   31    9.5
2012 Jul 11   06h 51m  +14d 14'  1.092 0.211   11    5.1
2012 Jul 21   09h 01m  +30d 30'  1.003 0.291   17    6.6
2012 Jul 31   11h 10m  +27d 03'  0.894 0.587   35   10.0

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

In the Transient Sky – June 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.

June 2012 Highlights
* Transit of Venus on June 5
* Partial Lunar Eclipse on June 3 
* Venus rockets out into the morning sky
* Mars fades but still is high in the evening sky
* Saturn is easily seen in eastern evening sky
* Mercury starts a nice apparition 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>.

Partial Lunar Eclipse

The Moon follows up last month’s annular eclipse with a partial eclipse on the morning of June 4th. The eclipse can be seen  North and South America, Australia, eastern parts of Asia and all across the Pacific Ocean. Only 37% of the Moon will enter the umbra so it will be far from a total eclipse. Here in the US, the Moon enters the dark umbra at 10:00 UT (6:00 am EDT, 5:00 am CDT, 4:00 am MDT, 3:00 am PDT). Maximum eclipse occurs an hour and three minutes later. For more information on when and where this event can be seen go to Science News @ NASA Science.

Venus Transit of the Sun

On June 5th, Venus will pass in front of the Sun for the first time since 2004 and the last time till 2117. For more info please visit the Transit of Venus website.

Planets

Evening Planets

Mars - Mars is the brightish reddish “star” to the SW early in the evening. Mars reached opposition (the point opposite the Sun on the sky) in early March. In June, it fades from +0.5 to +1.0. The red planet will spend the month moving eastwards from the constellation of Leo into Virgo. The Moon visits on the evening of the 25th and 26th.

Saturn - Saturn reached opposition on April 15 at a distance of 8.75 AU (813 million miles or 1.3 million km) from Earth. This month it continues making a nice but distant pair with the bright 1st magnitude Spica. Both can be seen to the South at the end of twilight. Saturn will fade from magnitude +0.5 to +0.7. The Moon visits on the mornings of the 27th.

Morning Planets

Mercury – This month Mercury starts a rather good apparition for northern observers in the evening. It reaches its highest point above the horizon on June 22.

Jupiter – A month past conjunction with the Sun, Jupiter can be seen slowly rising out of morning twilight. During the later half of the month Jupiter and Venus make a nice pair once again (similar to their showing this Spring in the evening) against the backdrop of the Pleiades and Hyades clusters of Taurus. The Moon is located near Jupiter on the morning of the 17th.

Venus  – After its spectacular transit of the Sun on the 5th Venus enters the morning sky. Not quite reaching as high as Jupiter, the brightest planet will be easy to see just before the start of morning twilight by the end of the month. The Moon pays it a visit on the morning of the 18th.

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 start to tic upwards in June.

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 June mornings, 7 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)

None

Small Telescope Comets (V = 8.0 – 10.0)

Comet 96P/Machholz

Comet 96P/Machholz is the only comet that may be brighter than 10th magnitude this month. And even then it will only be brighter than 10th magnitude for the last day or two of the month. Next month the comet will be much brighter though it will also be located closer to the Sun.

This comet has one of the smallest perihelion distances of any short-period comet at 0.12 AU. For this go-around, the comet will reach perihelion on July 14. During June it will only be visible from the Southern Hemisphere. Northerners will get their chance towards the end of July. At the start of June, it will be located 1.19 AU from the Sun and 1.17 AU from Earth. Though rapidly brightening it will still only be a faint magnitude 14. By the end of the month the comet will have brightened to magnitude 10 or a little brighter. It will close out the month at a distance of 0.55 AU from the Sun and 0.95 AU from Earth.

Don Machholz first spotted 96P back on May 12, 1986 at magnitude 9.7. Though the comet can get very bright (up to magnitude -2) it is always located too close to the Sun for observation when that bright. By the time the comet has moved far enough from the Sun for easy observations it will have faded to 8th or 9th magnitude. It currently takes ~5.3 years to orbit the Sun.

Date            RA        DEC    Delta   r   Elong    V
2012 Jun 01   01h 59m  -31d 44'  1.168 1.190   66   14.2
2012 Jun 10   02h 58m  -26d 41'  1.031 1.015   59   13.1
2012 Jun 20   04h 12m  -17d 24'  0.942 0.798   48   11.7
2012 Jun 30   05h 27m  -04d 13'  0.949 0.549   32    9.8

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
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