February 2009 Observing Guide

OBSERVING GUIDE
(Please note all times are UT and are based on an observing location of Belfast and covers the month of February)

The Sun

At the start of the month the Sun rises at 08:15 and sets at 17:05. By the end of the month, it rises at 07:15 and sets at 18.00.

The Planets

Mercury is a morning object this month rising low in the South-East and is at greatest western elongation on the 13th. However it is not well placed for observation this month due to the plane of solar system being at a shallow angle with the horizon. This also affects the other morning planets Mars and Jupiter. At the start of the month it rises over an hour before the Sun at 07:00 and is mag +0.6. On the 13th, it rises an hour before the Sun at 06:50 and by month’s end it has moved back towards the Sun and is not observable.

Venus is well placed for observation in the West after sunset this month. At the start of the month it sets at 21:40 and by month’s end; sets at 21:45. It maintains its brightness at mag -4.6 during the month.

Mars is poorly placed for observation this month.

Ceres is at opposition on the 25th and is predicted to be mag +6.9 at peak brightness. It can be located in Leo. It starts the month around a degree to the North-East of the mag +2.5 star Delta Leonis (Zosma) and moves to the North-West throughout the month. By month’s end it lies around a degree to the South-East of the mag +4.2 star 54 Leonis. This is a good opposition for the dwarf planet as its magnitude can vary between mag +6.7 and mag +9.3 at opposition. A finder chart can be found in a link in the information sources at the bottom of the guide.

Jupiter is also poorly placed for observation this month. Even at month’s end, it rises less than an hour before the Sun at 06:35.

Saturn can be located in Leo this month. It rises at 20:30 at the start of the month and by month’s end; it rises at 18:30. It brightens from mag +0.7 to mag +0.5 during the month. With the planet’s ring plane almost edge on, this is not a good time to try and observe the rings. It is however a good time to try and observe the smaller satellites and details on the planet’s surface with the rings out of the picture. It lies close to Sigma Leonis (mag +4) through out the month.

Uranus can be found in Aquarius and this month sinks into the evening twilight. At the start of the month, it sets at 20:40. By month’s end it sets at 19:05. It is just within naked eye visibility and maintains its brightness at mag +5.9 during the month.

Neptune is at conjunction on the 12th and is too close to the Sun to be observed this month.


The Moon

The first quarter moon is on the 2nd with the full moon on the 9th. The last quarter moon is on the 16th with the new moon on the 25th.

On the morning of the 4th, a 62% illuminated waxing gibbous moon occults M45 – The Pleiades. The timings for this are from around 01:40 through to moonset around 04:00.

On the evening of the 6th, a 89% illuminated waxing gibbous moon occults the mag +3.0 star Epsilon Germanium (Mebsuta). Start looking from around 19:10 for its disappearance; it then reappears around an hour later from behind the moon’s bright edge from around 20:10.

On the evening of the 8th, the rising near full moon lies three degrees South-East of M44 - The Beehive Cluster.

On the evening of the 27th, an 8% illuminated waxing crescent moon lies less than four degrees South-West of Venus.

Meteors

The ZHR or Zenithal Hourly Rate is the number of meteors an observer would see in one hour under a clear, dark sky with a limiting apparent magnitude of 6.5 and if the radiant of the shower were in the zenith. The rate that can effectively be seen is nearly always lower and decreases as the radiant is closer to the horizon. The Zenith is the overhead point in the sky for an observer. The radiant is the point in the sky, from which (to a planetary observer) meteors appear to originate, i.e. the Perseids, for example, are meteors which appear to come from a point within the constellation of Perseus. A fireball is defined by the International Astronomical Union as a meteor brighter than any of the planets, i.e. magnitude -4 or brighter. The International Meteor Organisation alternatively defines it as a meteor which would have a magnitude of -3 or brighter at the zenith.

There are two showers this month. They are both minor in nature. The first is the Aurigids which peak between the 5th and the 10th. The predicted ZHR is 2 and the shower suffers from heavy lunar interference with the peak clashing with the full moon. The second shower is the Delta Leonids which peak on the 25th. The predicted ZHR is 2 and the shower suffers no lunar interference with the peak coinciding with the new moon.

Comets

Comet/2007 N3 (Lulin) is currently estimated at mag +7 with it predicted to reach a peak brightness of mag +6 between the 21st and 25th. If correct, it will be on the verge of being naked eye and should be visible in binoculars. It starts the month in Libra and travels in a North-Westerly direction. It passes through Virgo and ends up in Leo by month’s end. At the start of the month, it is visible from around 04:00. By mid-month, it is visible from around midnight and from 19:00 by month’s end. On the morning of the 2nd, it lies roughly halfway between the stars Sigma and Beta Librae (mag +3.3 and +2.6).

On the morning of the 6th, it passes less than a degree to the North of Alpha Librae (mag +2.. On the morning of the 16th, it passes three degrees to the North of the mag +1.0 star Alpha Virginis (Spica). On the morning of the 20th, it passes close to asteroid 29 Amphitrite which is mag +10. The pair are closest at around 10:00 which is not well placed for us, but it will make for a nice observation in the pre-dawn hours. On the morning of the 24th, the comet passes two degrees to the South of Saturn. On the evening of the 27th, it passes less than a degree to the South of the mag +1.4 star Alpha Leonis (Regulus).

Comet 2006 W3 Christensen moves away from Lacerta towards Pegasus during the month. It is predicted to remain around mag +10 for the month with long term predictions of mag +8 by the summer months. This comet is slowly slipping into evening twilight, but in turn becoming visible before sunrise. It slips below the horizon around 22:00 at the start of the month and by month’s it is no longer visible around 20:00. However also by month’s end, it becomes visible low in the East and is visible from about 05:00.

Comet 144P/Kushida is currently estimated at mag +9 with it predicted to maintain similar brightness during the month. It can be located in Taurus, moving through the constellation in an Easterly direction towards Gemini. At the start of the month, it lies near to the Hyades and the mag +0.9 star Alpha Tauri (Aldebaran). Around the 18th-19th of the month, the comet passes by the two open clusters NGC 1807 and 1817. It then passes through the open cluster Collinder 65 between the 21st and the 27th.By month’s end it lies approximately three quarters along an imaginary line between the mag +0.4 star Alpha Orionis (Betelgeuse) and Zeta Tauri (mag +3.0), which itself is close to M1 – The Crab Nebula.


Deep Sky

On the deep sky front this month, galaxies M81 and M82 can be observed in Ursa Major. In Andromeda, M31 – The Andromeda galaxy can be observed along with its satellite galaxies M32 and M110. In Perseus, there is the open cluster M34 and the excellent Double Cluster – NGC 869 and 884. In Triangulum, there is the galaxy M33. In Auriga there are three open clusters M36, M37 and M38 and also M35 in Gemini. Taurus has the excellent Pleiades – M45, the Hyades and also M1 – The Crab Nebula. In Orion there is M42 – The Great Orion Nebula. In Canis Major there is the open cluster M41. Another open cluster M50 can be found in Monoceros and also Cancer has its open clusters with M44 – The Beehive Cluster and M67. Check out the constellation Canes Venatici with the globular cluster - M3 and several galaxies including M51 - the Whirlpool Galaxy and M63 - the Sunflower Galaxy. In Leo, we have several galaxies on view including The Leo Triplet - M65, M66 and NGC 3628. M95, M96 and M105 can also be observed in Leo. The place to really find galaxies is in Virgo. The Virgo Super Cluster can be found here with numerous galaxies on view. Also in Virgo, M104 - the Sombrero Galaxy can be found. In Coma Berenices, there is M64 - the Black-Eye Galaxy.

For further observing information, check out
www.eaas.co.uk/index.php?option=com_cont...=blog&id=6&Itemid=11

General Notes

Always keep an eye out for Aurorae. Check out www.stronge.org.uk/spaceweather.html for the most up-to-date information on the aurorae. Other interesting naked eye phenomena to look out for include the Zodiacal Light and the Gegenschein. Both are caused by sunlight reflecting off dust particles which are present in the solar system.

The Zodiacal Light can be seen in the West after evening twilight has disappeared or in the East before the morning twilight. The best time of year to see the phenomenon is late-Feb to early-April in the evening sky and September/October in the morning sky -- it's then that the ecliptic, along which the cone of the zodiacal light lies, is steepest in our skies. The Gegenschein can be seen in the area of the sky opposite the sun. To view either, you must get yourself to a very dark site to cut out the light pollution. When trying to observe either of these phenomena, it is best to do so when the moon is below the horizon. If you are observing them when the moon has risen, restrict your efforts to the period 4 days either side of the new moon as otherwise the moonlight will be sufficient to drown them out.

Finally check out www.heavens-above.com for the latest passes of the International Space Station and satellites, details of Space Shuttle launches and passes and for details of Iridium Flare activity.

Clear Skies and See You in Galway on Friday

Neill McKeown

Information Sources Used

www.skyviewcafe.com - Used for the Sun and Planets section. Also partly used for the Moon Section

Sky at Night Magazine Observing Guide and Interactive Planetarium

www.aerith.net and cometchasing.skyhound.com – Used for the Comet Section for information and finder charts

www.imo.net – Used in the Meteor section

BAA Handbook

Stardust Magazine

Sky Guide 2009 – South Dublin Astronomical Society

www.rasnz.org.nz/MinorP/09Ceres.htm - Finder Chart for Ceres

Great work Neill as usual, thank you.

Michael.

Looking good Neill, always a resourceful little tool...





...your sky guide, I mean!