Star trail capturing and processing

Hi All,

I’m a novice astrophotographer planning to capture a star trail photo. I’ll be using a crop sensor camera and shooting 15s frames at f/2 with a 50mm lens for 2 hours. That should give me roughly 480 frames. My plan right now is to capture all those frames in RAW and use Siril to stack them. I’m estimating this to be around 34GB of data. I looked around and saw that Siril doesn’t have a gap filling mode, is there a way I can use GIMP for gap filling? I’d appreciate any suggestions to improve this workflow and whether using RAWs is even worth it in this case given then amount of data I’ll have to deal with.


Hi, sorry we missed your question; I don’t know what gap filling means in the context of star trails, I’m not sure what you mean by crop sensor either, do you mean you acquire with a region of interest enabled?

Crop sensor: a sensor smaller than the old 24×36 film slides, usually 2/3 of the size. The effect is a smaller angle of view for a given focal lenght (or larger “effective focal length” as far as field of view is concerned).

With “Gap filling” OP is probably asking about an automatic way to fill in the holes in his star trails between individual captures.

Thank you.

Indeed, Siril only processes data it has, it doesn’t invent anything. I don’t know if GIMP will do that.
No problem for the processing of 500 frames anyway.