[ioulian]

I hear a lot of astrophotographers take many short-exposure (5-10s) photos and then stich them together in POST. Missing 1 of possible 100 photos in OK I think?

Keeping in mind that you photographing a specific thing in the sky, not the startrails, as missing a frame will be very visible there.

[_aavaa_]

Sub exposures are taken explicitly to avoid this issue. It also lets you easily to be planes and satellites.