(Please note all times are ST and are based on an observing location of Belfast and covers the month of April)
At the start of the month, the Sun rises at 07:00 and sets at 20:00. By month's end, it rises at 05:50 and sets at 20:55.
Mercury is at greatest western elongation on the 11th, but is not easily visible during the month.
Venus is not easily visible this month.
Mars is visible in the evening sky during the month in Taurus. It fades from mag +1.5 to mag +1.6 during the month. It sets around 00:40 during the month.
Jupiter is a morning object this month in Ophiuchus. At the start of the month, it rises at 02:45 and by month’s end, it rises at 00:50. It brightens from mag -2.1 to mag -2.3 during the month.
Saturn is at western quadrature on the 10th and is visible in the morning sky this month in Sagittarius. At the start of the month, it rises at 04:30 and by month’s end it rises at 02:35. It brightens from mag +0.6 to mag +0.5 during the month.
Uranus is at conjunction on the 23rd and is not visible this month.
Neptune is not easily visible this month.
The new moon is on the 5th (09:50) with the first quarter moon on the 12th (20:06). The full moon is on the 19th (12:12) with the last quarter moon on the 26th (23:18).
9th pm the 20% waxing crescent lies E of Mars and N of Aldebaran (Alpha (α) Tauri, mag +0.9) at 22:00.
14th pm the 73% waxing gibbous lies W of Regulus (Alpha (α) Leonis, mag +1.4) at 22:00.
18th pm the near full moon lies N of Spica (Alpha (α) Virginis, mag +1.0) at 22:00.
22nd am the 92% waning gibbous lies N of Antares (Alpha (α) Scorpii, mag +0.9) at 02:00.
23rd am the 85% waning gibbous lies NW of Jupiter at 02:00.
25th am the 67% waning crescent lies W of Saturn at 04:00.
The best time to observe meteor showers is when the moon is below the horizon; otherwise its bright glare limits the number you will see especially the fainter ones. Below is a guide to this month's showers.
The Lyrids peak on the night of the 22nd/23rd at around midnight with a ZHR of 18. The radiant which is near Vega is visible as soon as darkness falls, but is very low at the start of the evening and is at its highest at dawn. The meteors are of a medium speed (30 miles/second) and can produce fireballs. The best observing of the shower this year will be before the 85% waning gibbous moon rises in Ophiuchus at 00:30 on the 23rd.
There may be additional minor showers this month, details of which can be found in the below Information Sources and Links Section.
Asteroid (2) Pallas is at opposition in the morning of the 10th at mag +7.9 in Bootes. It is visible from 21:00 on the evening of the 9th and lies near to Muphrid (Eta (η) Bootis, mag +2.7).
Asteroid (7) Iris is at opposition during daytime on the 5th at mag +9.4 in Corvus. It is visible from 22:00, low in the South on the nights of the 8th/9th and 9th/10th.
Asteroid (44) Nysa is at opposition on the 24th at mag +9.9 in Virgo. It is visible from 21:00 on the evening of the 24th.
Finder charts and further information about other fainter asteroids can be found in the below Information Sources and Links Section.
There are no bright comets visible this month.
Finder charts and further information about the above and other fainter comets can be found in the below Information Sources and Links Section. Any of the above estimates are based on current information at the time of writing the guide and can be wrong - “Comets are like cats; they have tails, and they do precisely what they want”, David H Levy.
On the deep sky front this month, galaxies M81 and M82 can be observed in Ursa Major. 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 Cancer - M44 - The Beehive Cluster and M67.
Always keep an eye out for 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. A new appendix has been added explaining some of the more technical terms used in the guide.
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.