The Tail of the Serpent

One of my favorite spaces of the sky for just random stargazing is Serpens Cauda, or the Tail of the Serpent, along with the neighboring western edge of giant Ophiuchus. Just gliding up and down the length of this, to the naked eye rather unimpressive constellation, one discovers fields of view crammed full of stars, some belonging to open clusters with formal catalog designations, and others simply strung together in anonymous asterisms and star streams - but all of it just plain beautiful.

IC 4756

Start by taking a look at IC 4756, perhaps the jewel of the whole area. First off, this open cluster is HUGE - almost twice the size of the full moon. But in the eyepiece it looks even larger than that, due to its sitting right on top of the Milky Way. So there are stars, stars, stars everywhere - impossible to tell where the cluster ends and the background stars begin.

NGC 6633 (off to the right)

Right next to IC 4756 and just over the border into Ophiuchus is NGC 6633. The two clusters' proximity ro each other is due to chance line of sight alignment. IC 4756 is more than 13,000 light years away from our Solar System, while "neighboring" NGC 6633 is a mere tenth of that distance from us. So it is obvious that it is much the smaller of the two. NGC 6633 occupies an area of the sky roughly equivalent to one full moon. Like its sprawling neighbor, it is nearly impossible to determine just where  the cluster ends, end everything else begins.

From here we stray into the realm of uncataloged asterisms, whirls, knots, and streams of stars, like a turbulent river sliding off to the southeast, ending up in Ophiuchus at Poniatowski's Bull (see my posting to this blog on September 17, 2017). This V-shaped asterism resembles in miniature the Hyades open cluster in Taurus, and contains a number of attractive double stars.

I often spend time with the serpent's tail when I just want to relax and "take it all in" without looking for anything in particular.