M13 – The great cluster in Hercules
I have decided that I dont get on with my SCT imaging wise – the stars are always blobby with horrible colour and the vignetting was driving me nuts! So….. I have now got hold of an 8″ F4 Imaging Newtonian from Altair Optics. It’s not perfect – the collimation is a nightmare, the focuser needs replaced as it’s horrible BUT, the stars are not bad with the limited collimation and the colours are really nice, so it’s a keeper……. So far!
This is the first real image from it, I had a couple of false starts and the collimation is a nightmare, I had to find the target and then collimate when I was on target, hence the need for a new focuser! The image is a stack of 2 min subs, making a total of 1hr 58mins of integrated exposure.
Anyway here is M13 – the great globular cluster in Hercules. Globular clusters are massive collections of gravitationally bound stars at the very edge of the galaxy, one theory is that these are failed galaxies. There are over 300,000 stars in this cluster, it can be seen easily with smaller amateur instruments as a small fuzzy ball, with 4.5″ scopes starting to be able to resolve a few individual stars.