April Sky Guide

Hi all,

April's sky guide is below. Enjoy.

OBSERVING GUIDE
(Please note all times are BST and are based on an observing location of Belfast)

The Sun

At the start of the month the Sun rises at 06:55 and sets at 20:00. By the end of the month, it rises at 05:45 and sets at 20:55.

The Planets

Mercury is at superior conjunction on the 16th and as a result is too close to the Sun for observation for most of the month. However after superior conjunction it becomes an evening object low in the West/North-West. It is well placed for observation from the 24th onwards when it sets an hour after the Sun. By month’s end it sets at 22:40, more than an hour and a half after the Sun with a mag of -0.9.

Venus is a morning object this month. However it rises only shortly before the Sun and is badly placed for observation this month.

Mars is still well placed for observation although it is fading. It rises during daylight hours and can be found in Gemini. It fades from mag +0.8 to mag +1.2 during the month. By month’s end it sets at 03:10.

Jupiter is a morning object this month and can be found in Sagittarius. At the start of the month, it rises at 04:25 and by month’s end, it rises at 02:35. It brightens from mag -2.2 to mag -2.4 during the month.

Saturn is still well placed for observation this month. It rises during daylight hours and can be found in Leo. It fades from mag +0.4 to mag +0.5 during the month.

Uranus is a morning object this month, although it is badly placed for observation and only rises an hour before the Sun by month’s end.

Neptune is a morning object this month. It can be found in Capricornus. At the start of the month, it rises more than an hour before the Sun at 05:45 and by month’s end it rises two hours before the Sun at 03:50. It brightens from mag +8.0 to mag +7.9 during the month.

The Moon

The new moon is on the 6th with the first quarter moon on the 12th. The full moon this month is on the 20th. The last quarter moon is on the 28th.

On the evening of the 6th, a 15 hour old moon may be observed in the West just after sunset. Please be sure that the sun is below the horizon before attempting this. Moonset will be around 21:15, an hour after sunset.

On the evening of the 8th, a 10% illuminated waxing crescent moon lies close to M45 – The Pleiades, to the West of the cluster.

On the evening of the 10th/morning of the 11th, a 29% illuminated waxing crescent moon lies between M35 in Gemini and the grouping of M36, M37 and M38 in Auriga. It lies to the North-West of M35 and to the South of M36, M37 and M38.

On the evening of the 11th/morning of the 12th, a 41% illuminated waxing crescent moon lies close to Mars.

On the evening of the 13th, a 61% illuminated waxing gibbous moon is seen to pass through M44 – The Beehive Cluster.

On the evening of the 15th, a 80% illuminated waxing gibbous moon lies close to Saturn to the South of the planet.

On the morning of the 27th, a 64% illuminated waning gibbous moon lies close to Jupiter to the South of the planet.

Meteors

There is one major shower this month and also two minor showers. The major one is the Lyrids. They peak on the morning of the 22nd at around 04:00. The predicted ZHR is 10 - 18, but outbursts have occurred in the past, raising the ZHR to around 100. The radiant is located near to Vega. There will be major lunar interference for this shower with a 97% illuminated waning gibbous moon setting at 06:00 on the morning of the 22nd.

The two minor showers are the Virginids which peak on the evening of the 10th and the Gamma Virginids which peak on the evening of the 14th. Both have a low ZHR of 5 with the Virginids faring better with lunar conditions with a 30% illuminated waxing crescent moon setting at 03:10 on the morning of the 11th. For the Gamma Virginids, there will be some interference with a 72% illuminated waxing gibbous moon setting at 04:55 on the morning of the 15th.

Asteroids

Asteroid (7) Iris is at opposition on the 5th and can be located this month in Virgo, South of Spica (Alpha Virginis). At opposition it is mag +9.4 and fades to mag +9.9 by month’s end.

Comets

Comet 17P/Holmes can be located in Auriga for the month of April. It is fading with current observations estimating its brightness at mag +5.1. Iota Aurigae (Hasselah) can be used to locate this comet. It lies North-West of the star at the start of month moving in an Easterly direction and by mid-month, it has moved into the main body of the constellation, lying North of Iota Aurigae. For the second half of the month, it lies North-East of the star.

Up to date information and finder charts for comets can be found at www.aerith.net and
www.skyhound.com/sh/comets.html

Deep Sky

On the deep sky front this month, The Double Cluster – NGC 869 and NGC 884 makes for a great sight in Perseus. In Ursa Major – galaxies M81 and M82 can be observed. 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. Also 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 Hercules, two globular clusters – M92 and the excellent M13 can be observed and in Lyra – M57 – The Ring Nebula can be observed. Finally there are some excellent open clusters in Auriga, Gemini and Cancer - M35 in Gemini, M36, M37 and M38 in Auriga and M44 – The Beehive Cluster and M67 in Cancer.

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

Neill McKeown

Thanks Neill once again for a fantastic guide!

A new bright Comet C/2007 W1 Boattini can be located in April low in the South. It is currently in Corvus, moving into Crater by mid-month and into Hydra by month’s end. Current observations make the comet mag +9.5 with further brightening to come. It passes close to two galaxies in Corvus on the evening of the 8th, details are below.

Date Time (BST) Dist. (deg) Comet Mag. Target Type Mag. Con
Apr. 8 21h 0.82 C/2007 W1 ( Boattini ) 9.8 NGC 4027 galaxy 11.1 Corvus
Apr. 8 22h 0.13 C/2007 W1 ( Boattini ) 9.8 NGC 4024 galaxy 12.7 Corvus

Comet Holmes also has several close encounters in April which are detailed below.

Date Time (BST) Dist. (deg) Comet Mag. Target Type Mag. Con
Apr. 20 21h 0.89 17P/Holmes 5.4 NGC 1778 open 7.7 Auriga
Apr. 29 2h 1.59 17P/Holmes 5.5 IC 405 nebula - Auriga
Apr. 30 22h 2.45 17P/Holmes 5.5 NGC 1893 open 7.5 Auriga
Apr. 30 22h 2.34 17P/Holmes 5.5 IC 410 cluster + nebula - Auriga


For details of all Cometary rendezvous with galaxies, nebulae and other galactic bodies, check out www.aerith.net/comet/rendezvous/current.html . For further info on visible comets in general, check out www.aerith.net

Sweet! Something interesting again! Glad to see the predictions give a decent magnitude for this comet...


...of course, all that can change over that time.

Seanie.

Danke shun neil