Quote:
Originally Posted by doppler
When using live view to focus on a star I find that it is best to use a high iso to focus (this will make any stars on the screen much brighter) then lower the iso to start taking images.
Rick
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+1
Get the focus done first. Point your camera at the moon and autofocus, or the brightess object in the sky (star/planet, doesnt matter) and set your focus before setting up to take photos. Once you have good focus its set for everything in the sky basically. Take it slow, there is usually some lag in camera live view and you might see a star vanish on screen or others appear, the better the focus the more live view pinpoints of stars you will see. Do this on a tripod, let the vibrations settle take a test shot at a faster shutter speed (try faster than 1/ (500/focal length) ) just as a test to zoom in on shot and look at the stars in the middle of the shot. They should look like little "soft" round blobs, they won't be sharp points (btw turn off in camera sharpening). They should not be discs that are bright at the edge and duller/uneven in the middle.
Your last two shots: the first is way out of focus, the second much better but not sure DSS will work with trees/roofs in shot but otherwise the stars in that shot should be in focus enough.
I played with DSS myself last night, threw it a bunch of shots i took a few nights ago, lights, darks, flats, bias all as jpgs (current dss doesnt support the raw from the camera i used). no problems with star detection etc at all. Not a recommended way of processing, I just tried it for fun to see if anything else came to mind to help you out.
Are you using the latest version of DSS from the yahoo group or the one on the website? (link to yahoo group is on the website too). I think the way its star detection works is to look for a round feature that quickly increases in brightness from the background to a peak then quickly falls off the other side. Out of focus stars do not look like this to the software.
As an exercise, you could try batch processing your shots to resize to a quarter size or possibly throw on a small guassian blur to turn the out of focus stars into better dots. These you should be able get DSS to work with. Certainly warmer than taking more test shots. When I get slight focus problems or reprocess shots to bring out a deep space object near a corner where lens distortion is common I manually register in pixinsight and can use star masks and other techniques tomake the stars a bit rounder. While others may throw away the data and reshoot later I am still happy with signal I can pull out of the poor data, it all helps refine my skills.