Deep-Sky Observing

Abstract

Jumping now “into the great beyond” of deep space, we begin with two types of typically very large and scattered collections of stars. Though generally unrelated, they both require very wide fields of view to be seen to advantage, giving binoculars and RFTs a definite edge over normal telescopes. Stellar associations are actual physical systems very loosely bound by their mutual gravitation, much like star clusters themselves (see below) but covering many degrees of sky rather than many minutes of arc and much less concentrated. One of the brightest, best-known and most spectacular of these is the Alpha Persei Association—a radiant splash of stellar gems surrounding the 2nd-magnitude star Mirfak in the constellation Perseus, visible in the skies of fall and winter. The view here in binoculars on a dark night is truly spectacular!