Strange and sparkly EEA of the Perseus double cluster

[timh]

A couple of nights ago I was demonstrating the use of Sharcap and EEA to someone who has just bought their first telescope. Warm indoors with a cup of tea - EEA has just so much to commend it as a means to observe many objects live in one night at a level of detail quite impossible at the eyepiece. It is amazing quite how good a 10 minute image can be.

However there are hazards -- especially because you can't see it you lose track of where the telescope is actually pointing. So we were both admiring this strangely attractive image of the double cluster as it built (just a live stack of 18 x 40s exposures in the 300 mm F4 Newtonian - As1294MC). Then I took the SC autostack - removed some background in PI using dynamic background extraction and then corrected the colour using SPCC.

I later realized that the telescope had taken these images through a thick bush of winter branches. I recall Brian (Oopfan) describing a cross hair device that he had put in front of his refractor in order to add diffraction spikes - well here is another method if ever you should want the stars to appear like this ?

[turfpit]

Good effort through a bush Tim. The star colours turned out well.

Dave

[admin]

Lovely!

I've done imaging through the branches of a tree before too, though not with such pretty results. You can get away with a lot with a fairly fast F-ratio, but slower setups are not so forgiving - the greater depth of field means that the obstructions are less out of focus.

cheers,

Robin