IOM July 2011 – Globular Cluster M56 [NGC6779] in Lyra

This month’s deep sky object is a Globular Cluster, this time M56 in Lyra.  Why?  Because I really like Globular Clusters with a Milky Way background – and this is what the M56 region offers us 🙂

M56 lies at a distance of 31,000 light years and shines at magnitude 8.4.  It is pretty small at a mere 7 arc minutes in diameter, so it would benefit from focal lengths in excess of 1,000mm – but having the Milky Way background makes this a good region for wide field imaging as well.

As usual with star clusters, we don’t need very long subs, anything from 3-5 minutes will be fine.  And if you want to get a nice glassy-smooth noise-free image at the end you will want to aim for around 80 – 100 subs in total.

As with all deep-sky portraits – the framing is all important, what other objects lie in the same frame to give the image that WOW factor?  In the case of M56 it is the Milky Way background that does this.  So a reasonable sub exposure length together with a nice large number of subs should yield a very impressive star image.

Fortunately, the evenings are once again starting to get slightly longer.  It’s still far from ideal for deep-sky imaging, but we have to feed the withdrawal symptoms somehow, and things start to improve by leaps and bounds once we get through next month.

So until August – clear skies to you all!!

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