First attempt at stacking for star trails

I know the foreground scenery is rubbish and the photos weren't in perfect focus but can anyone tell me how to improve other than taking more photos.

20" f4.5 iso 1600 40 photos

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Nice start. The wider the FOV the better. The longer you can leave the camera taking pictures the better. It helps big time to have and eternal timer/trigger to automatically take the pictures for you. You can use live view to focus to star with. Next take a pic using the timer or trigger to eliminate shaking from pressing the button (it looks like you are doing this just fine). you can zoom in on these pictures to make sure you are in focus. Make adjustments if necessary. Erase the test images, start it and leave it alone and have fun. I use Startrails and Startrax. Both are free

Thanks Toxic, I used startrails for this stack too. Really user friendly, but how important are dark files, bias files etc? I just put my 40 photos in the light file section ( I think ?) And got the image above.

I think you did a great job. All up that's only 13 minutes of exposure. Star colours look great.

I'm no expert, in fact this was my first and only attempt at star trails. My exposures were ISO1600, f/5.6, 5 minutes long each, and I think that was about 30 frames, giving over 2 hours worth of trailing.

I reckon you're on the right track, maybe just get some more foreground appeal and wider lens if possible. If you have a timer remote, go for longer subs. If not, go for many more subs.

As for darks/bias etc, probably not critical for 20-30 second exposures, although will help for noise. For 5 minute subs like mine, definite must. I didn't take any and when you look at it 100% there is a lot of noise, especially after a few frames have been taken and the sensor starts heating up. I should have taken at least some darks.

Do you know how to take darks and biases? Understand what they're for etc?

Love your pic Troypiggo. No I don't really know anything about darks or bias files other than I read to put the lens cap on and take a couple more shots on same settings and that should be good enough for darks. any help greatly rec'd.

These FAQ links from the Deep Sky Stacker website explain it better than I can:
http://deepskystacker.​free.fr …q.htm#lightdark​flatoffset
http://deepskystacker.​free.fr …sh/theory.htm#C​alibration

I'd take your "lights", ie the images you used above, first. Then I'd take darks, same ISO and shutter speeds as your lights, just put lens cap on, maybe take 10-20 of them. Then for biases, leave lens cap on, same ISO as above, but change shutter speed to the fastest your camera can do, take 10-20 of those too. Ideally the darks and biases are taken around the same time as lights so that temperatures are consistent. Don't worry about flats at this stage is my recommendation for star trails.