Rod Mollise invites you on a tour of seven spectacular spring galaxies around Ursa Major and shares his tips and tricks on how to see them
Spring has come to the Northern Hemisphere. The great globe of the heavens has rolled on and the brilliant star clusters and nebulae of winter are sinking in the west. It’s now that deep-sky observers turn their attention to the subtler marvels on the rise – the galaxies. In the north, the Great Bear, Ursa Major, and its neighbouring constellations, Canes Venatici and Coma Berenices, are riding high. The area is home to countless island universes, some of which will be our destinations tonight.
No object in the sky is more harmed by light pollution than galaxies. The first thing you learn about galaxy observing is: the darker the sky, the better. Many can be seen in suburban skies, but to see details, to observe anything in most galaxies other than their bright central regions, you’ll need to get to the darkest location you can access.
▶ Whether your skies are bright or dark, however, there are tips that can help you. Being able to not just see galaxies, but see them well, requires learning a few tricks of the trade to deal with the challenges they present. We’ll use these tips and tricks tonight as we wander from galaxy to galaxy.
Dive into the Whirlpool
Our first galaxy, M51, the Whirlpool Galaxy, is not technically in Ursa Major, but is close to it, in the small constellation Canes Venatici, the Hunting Dogs. The galaxy lies only 3.6° southwest of Alkaid, the star at the end of the Plough’s handle. This is not a difficult object to find, even without the aid of computerised Go-To telescope pointing.
The Whirlpool Galaxy is a face-on spiral galaxy, and that causes problems for the visual observer – its light is spread out across the eyepiece field, making it difficult to see no matter its magnitude. Luckily, the Whirlpool is small enough at 9.8 x 7.8 arcminutes that its mag. +8.7 light is still fairly concentrated.
What will you see? With a 6-inch reflector from light-polluted suburban skies, I see two blobs, a big one and a small one, the small one being the irregular galaxy NGC 5195 that is interacting with the Whirlpool. As aperture goes up and the skies get darker, however, this galaxy begins to look like its photos. With a 12-inch reflector from a southwestern US
