Perseus Double Cluster

[mickw]

I knew it wouldn't be long before started blowing things up 

Very nice image Robert

[RobertM]

One possible explanation is that the camera cables (which are quite thick) are causing it - look at the direction of the spikes - they are all aligned exactly the same way as the elongation. 

On the basis that a curved spider vane creates self cancelling diffraction artifacts i.e. no spikes, could you put in a curved cable guide e.g. a bit of coat hanger wire, attach the cables and get rid of those pesky spikes? Not that I can see any spikes - must get an eye test soon!

Thanks Duncan, I'll give that a go.