The days and twilight have taken over the skies, but still there’s astronomy to be done. As evening falls and Venus shines in the West, Saturn glows in the East and Mars above, the planets put on a show. As ever, this post is illustrated with a few sky charts showing midnight on the first, last and fifteenth day of the month. The dots represent brighter stars, green circles are star clusters, nebulae, galaxies and the like and the very brightest stars, the Moon and the planets are named when they appear. Sky charts provided using Stellarium.
The Moon will be in the last quarter phase on the 6th, new on the 14th, first quarter on the 21st and full on the 28th. On the 9th and 10th, it will be close to Jupiter at dawn. On the 16th, it will be close to Venus in the daylight, closest approach at 10am. On the 17th at 22:24, it will occult the 6.4th magnitude star TYC 1357-02074-1; on the 22nd at 00:07, it will occult another 6.4th magnitude star, TYC 0255-01196-1; on the 28th at 2am, the Moon will occult the star Sigma Scorpii, releasing it after one hour.
The Eta Aquarid meteor shower will be active on the night of the 6th, strengthening towards dawn. It is not particularly active, with perhaps 15 meteors an hour at most expected. A bright Moon won’t help. Further details here. The AntiHelion source is a shower from the antisunward direction of a few meteors an hour, which is active at the moment.
Heavens above presently lists six comets above magnitude 12 and seven asteroids above magnitude 10 in the hours of darkness. The comets are: C/2009 K5 McNaught at 9.7 at Cepheus, rising to 8 by the last day of May, when it will be in Andromeda; 81P Wild 2 at 10.0 between Virgo and Libra; 10P Tempel 2 at 10.1 in Aquarius; C/2009 R1 McNaught at 10.6 between Pegasus and Pisces; 141P Machholz at 11.1 in Pisces and C/2007 Q3 Siding Spring at 11.9 in Draco. The asteroids are 4 Vesta at 7.4 in Leo, 1 Ceres at 7.9 in Sagittarius – appearing near to the Lagoon Nebula, M8 on the 31st, 2 Pallas at 8.6 in Corona Borealis, 12 Victoria at 9.5 in Libra, 532 Herculina at 9.6 in Leo, 7 Iris at 9.7 in Pisces and 3 Juno at 9.8 in Taurus, appearing just after sun set. Pluto is also in Sagittarius, shining at magnitude 14.
Mars is on the home stretch to the Sun now. It is fifty degrees high in the sky at sunset and shines at magnitude +0.7, falling to +1.1 by the end. Its angular size falls from 7.3 arcseconds to 6 arcseconds in the same period, making details hard to spot.
Venus is now prominent in the evening skies just after sunset. Shining at magnitude -3.9, it is the brightest thing in the night sky after the Moon. It appears in the south-west once the Sun has gone down and has an angular diameter of 11.4 arcseconds, showing phases like the Moon, rising to almost 13 arcseconds by the end of the month. It gets higher and higher above the horizon at sunset with each day of the month.
Mercury has passed in front of the Sun, but will appear in the morning skies by the end of the month, with its greatest distance from the Sun before sunrise on the 26th. It won’t reach any great height in the sky, only about five degrees, you’ll need a clear horizon to the East to see it.
Saturn is past opposition, meaning its apparent diameter is now falling from about 20-18 arcseconds over the course of the month. It presently shines at +0.8, fading to +1.0 by the end of the month. The angular size of the slender rings extending to ~40 arcseconds. Those rings will get thinner and thinner until the end of June, when they’ll open up again. The bright moon Titan shines at 7.8 and will be easily visible in small scopes and binoculars (unless it is in front of or behind the planet at the chosen viewing time).
Jupiter rises in twilight at the start of the month, shining at -2.1, but appears at 02:30 by the end, shining at -2.3. Not much detail visible, but the Galilean moons should be visible in even small telescopes. The planet approaches Uranus during May and increases in diameter from ~35 arcseconds to ~39.
Uranus is also a morning object, shining at 5.7 in Pisces, with an angular size of 3.7 arcseconds. From the end of May, it will be joined by Jupiter.
Neptune is also in the morning skies, shining at 7.9 with a 2.3 arcsecond disc in the middle of Aquarius.
A few things outside the solar system
Leo holds the southern spot at sunset, with Cancer to the west of it. In Cancer, not far from Mars, is the Beehive Cluster of stars, good to observe on a dark night. The constellations of Leo, Virgo and the Big Dipper are all home to galaxies, details here.
The Usual Stuff
If you want to watch satellites flaring or passing in the sky (even sometimes during the day), then go to Heavens Above to get times and directions. If you need assistance in deciding where things are in the sky, why not install the free program Stellarium, which does all the work for you? Finally, to avoid the dreaded clouds, Met Check gives a quick forecast and the Met satellites or other satellites can be used to track breaks in the cloud. For an indication of auroral or solar activity, SpaceWeather.com is an invaluable resource. If the stars aren’t available, there’s always solar astronomy. Projections of the Sun onto white card can show sunspots, when properly focused. A good filter (not an eyepiece filter) or a dedicated solar telescope will show better details. Never observe the Sun without filters and never with an inadequate, inappropriate or old (and therefore possibly with holes in) filter.
For young astronomers (ages 9-16) Space Explorers is run in Kendal Museum on the third Saturday of each month from 2:30-4:00 pm. The next edition is on the 22nd when we will be talking about Saturn. The Society for Popular Astronomy also has a sky map for young astronomers for May here.
Plus why not pop along to the Eddington Society, which meets at Kendal Museum on the first Monday of each month (except this month due to the bank holiday and beginner’s night – it has moved to the second Monday, the tenth)?
Don’t forget to check back here and on my twitter account for the latest astronomical events in this area.