Open cluster question

[Richard N]

I have been trying EAA on some open clusters, hoping to bring out the fainter stars. The problem is this leaves the foreground stars as big blobs. Any tips on getting a better dynamic range?  Using Sharpcap and mono camera. 

[bosun21]

Take shorter exposures and stack them. What camera are you using?

[PeterC65]

It's hard to get good images of bright and faint objects in the same field of view with EAA. The West Veil Nebula is a good example. The bright star 52 Cyg gets blown out in order to see any detail in the nebula.

Your camera will have better dynamic range at lower gain settings and you could try to select for this. If your camera switches from LCG to HCG then there will be two sweet spots, and the best one is probably just beyond the switching point.

You could also also try zooming in digitally on the fainter stars you want to see. I quite like figuring out what is the faintest star I can see in an EAA image. I zoom in digitally then compare with Stellarium. The best I've managed so far is a magnitude 17.5.

 

[Martin Meredith]

The advice to take shorter subs and stack is good. Another possibility is that you're seeing blown-out stars because of the way you're manipulating the histogram and/or black/white points. You need a curve that compresses the high pixel intensities at the expense of the low intensities. With the right curve you can get non-blown-out stars and fainter stars.

[Richard N]

Lots of good suggestions thanks. I’m getting the impression that a combination of better focus and tweaking the histogram more carefully will get me most of what I need. Thanks all.