April Night Sky

Mars comes to opposition in Virgo on 8 April. Its angular diameter will be about 15″ (less than half Jupiter’s), and brightness -1.4. It is quite far south in the sky, culminating at a little over 30 degrees. Mars is a frustrating planet for northern observers. Its orbit is quite elliptical, and because it is the next planet out from the sun from us , this means there is a big range in its distance, and hence apparent size, at opposition. This opposition is a relatively distant one, and quite far south. The closest oppositions are when it is in Sagittarius or Capricornus, which is pretty hopeless for planetary observing from the UK. But, for the next couple of months, we get our best chance to see Mars for the next couple of years. Let’s hope for good seeing!

April is also the best month for galaxies. Ursa Major and its galaxies are almost overhead, but they can be seen pretty well for much of the year. April is the best month for exploring the galaxies in ¬†Virgo and Coma Berenices. If you are using a telescope of 8″ plus, the problem here tends to be not finding galaxies, but working out which ones you are looking at – in some places you are likely to see several in the same field of view. There are few bright stars in this part of the sky to act as waymarkers.

I tend to do this following the advice that Dick Phillips gave me, which is to take a line from two of the bright stars at the rear end of Leo, so to speak – from theta through beta, and roughly as far again to the east. This takes you to 6 Coma Berenices, a 5th magnitude star that should just be visible with the naked eye (indeed if it isn’t, it’s probably a poor night for looking at galaxies!) As the map below shows, this is a good starting point for sweeping around the central and richest part of the galaxy cluster. If you get disorientated from time to time (I do), you can normally find your way back to it again or, if need be, start again.

Virgo Coma B Galaxies