Thursday 2 May 2013

The blank in space that is Ophiuchus

Last night I tried to re-confirm some of my previous observations, driving my eyes crazy looking for La Superba, Messier 51 and Messier 81 all of which seem to be right on the lowest fringe of binocular visibility from my garden. It was another lovely night to be out, although sky clarity seemed to be a little below the previous two nights excellent quality.

By about 1am, I noticed that the constellation of Ophiuchus was rising over the rooftops, and went and stood beneath a tree to block out a particularly annoying streetlight, and had a study of this large constellation. It represents the "father of medicine" Aesclapius IIRC,  commonly portrayed as holding the celestial serpent Serpens Cauda (the head) and Caput (the tail) about his shoulders. It is technically the 13th constellation of the zodiac, as part of it lies between Scorpius and Sagittarius, and the sun passes through every mid december.

It contains one of my favourite open clusters, the compact and prominent IC4665 in the north-east of the constellation near Beta and Gamma. It is such an attractive binocular object it always amazes me it is not in the Messier Catalogue, let alone the NGC. I observed it well last night, although it is not yet high enough to be clear of the haze and streelights.

Ophicuchus contains many Messier objects, chiefly a large number of globular clusters. As I have done many times before, I scanned the area looking for them, and saw nothing. Total zero! Ophicuchus may be very rich in globular clusters, but unfortunately it is totally lacking in a guide stars to help you find them; indeed when you sweep around the constellation, which always reminds me of a blown up Gemini in shape, there's barely a star within the outline to be seen.

It's as if someone has very carefully cut out the centre of the constellation with space scissors, and left a hole to the edge of the universe, giving me massive thoughts to contemplate as I sipped on my cider, and took pleasure in the night.

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