Best settings for clusters?

[Welrod50]

Hello all, tried a search for this and drew a blank, so I'll ask away... I have imaged a lot of clusters lately and the common issue I have is blown stars which are sharp, but are all white with no reds, yellows, blues etc captured. I'm using an unmodded Pentax Kx prime focus through the 130 PDS. My question therefore is this - what is the best iso/exposure combination for globulars and clusters to best capture at least some of the colours visible? Im processing with DSS and finishing off with Photoshop. Is this do-able with what I'm using? Cheers all Scott.

[Bizibilder]

To start off try taking a lot of short exposures, say 30 secs or 1min, and maybe 100-150 of them. Stack and see how you get on. the short exposures should allow you to "keep" some colour in the stars rather than blowing them to white. You may lose some very faint stuff but with the high exposure count you will also gain by reducing the noise in the image.

[RikM]

Another thing to try is to after stacking with DSS, save as a 16bit tiff and check the option to save with settings embedded but not applied. This preserves all the original colour data and you get all back in Photoshop. Don't do any of processing in DSS. The processing tools are only there to let you have a quick look at what you have captured, not to do the final processing. When you open the image in Photoshop, you will be presented with a black rectangle, but that is okay, all of the image data is in there waiting to be teased out, including the star colour. If you use the curves tools and keep the white point where it should be, you can get good star colour with DSLR images

Most people won't believe that, so if you really must fiddle with the image in DSS, click on the saturation slider and shove it up to +15% or so. It won't be as good as doing it properly in photoshop but it is quick.

[Welrod50]

OK, cheers guys. Roger, I was shooting iso 800 20 sec subs and getting stars blown, but I'll try shorter exposures. Rik, I believe you I'll give that a whirl!

[ollypenrice]

20 seconds shouldn't blow the star colour. Rik's is an interesting post because 95% of DSLR images show no significant star colour but the 5% that do show good star colour prove that it must be possible. It looks like Rik has given us an explanation.

Olly