Deepskystacker???

[bsmotorsport]

Hi, im after a bit of help on this one, I took 60+ images last night of the stars and on each picture I can see them reasonably clear. I want to stack them in raw format to maintain all the info. When I try deepskystacker I just get this

but when I use Startrails.exe program I get:

but it only uses the jpegs and I want to use raw to help in the PP. Where am I going wrong? I appreciate the location could have been better but I just wanted a crack at it before I went somewhere worthwhile. Any help much appreciated,
thanks
Stephen

 

[jgs001]

Stephen, what effect were you trying to achive ? A trails image ? What were the exposure settings on each frame ? Can you post a single frame as an example please ?

DSS is really used for stacking pinpoint stars not trails to increase the SNR of the images.

 

[bsmotorsport]

Glad you replied John i was wanting to try star trails for the first time with the sky been so clear. Im using d200 with sigma10-20. I was at 10mm with ISO at 100, 30 sec, f4.0, NR turned on and was using interval timer every 50 seconds. Battery died after 68 images so I didnt have any chance of taking any dark frames to use. This is just 1 frame on its own

Any tips would be gratefully received

 

[jgs001]

Stephen, sorry it's taken a while, I missed your reply. You shots are too short and the stars too still to get star trails. I've only tried one star trails shot, and I used 18mm, f3.5 iso100 for a single 10 minute exposure. I had intended to take a bunch of these and stack them, but my plans were interrupted. With that skyline, I'm not sure you would get away with those settings though as the image would be washed with light pollution. Also, I can't tell from the image, as there's not enough stars in it, but which direction are you facing in ? To get the most rotation you really want to include Polaris in the image. That gives you a non moving centre and maximum field rotation.

 

[bsmotorsport]

Thanks John, I was facing north west (ish) I couldnt face any closer to north as the full moon was so bright. Been honest I went in to this trial blind, I knew what I wanted to do but just though if I have a go with what i think is right I can work from there. If I faced the opposite direction there would have been much less light pollution (virtually none) but the moon would have ruined it. I now realise that deepskystacker is more geared towards showing static stars rather than trails by stacking multiple exposures and finding the stars within. So my question would be, if I do this again do I want lots of relatively short (30 sec) exposures or not so many very long (5mins+) exposures and stack them? Am I right in thinking that if I focus around polaris the stars will b e travelling faster than this example here and thus give better trails. Ive found an observatory near my town that I reckon would be a good place to try my next attempt. Thanks

 

[jgs001]

I know people that have had success with 30 second exposures but you have to ramp up the ISO to gather the light from the stars. Or keep the ISO real low and go for longer. The local LP conditions will be a deciding factor and you will need to experiment to get your optimum settings. Also as startrails doesn't accept RAW, shoot jpg. the smaller file sizes mean you can get a whole heap load more for combining... We're approaching new moon (Tuesday 28th) so the moon won't interfere for the next week or so, and in fact doesn't get up above the horizon now till late at night, so if you get a clear night, it's worth a try.