A simple question and maybe the answer is trial and error, but...
I want to take tracked wide field / Milky Way DSLR images, but when looking for a suggested exposure starting point, all I find are recommendations for avoiding star trails on static mounts. It's currently hot, hazy, cloudy and / or rainy (i.e, very poor transparency at best) so it's academic for now -- maybe until fall -- just trying to get my ducks in a row.
- Star Adventurer 2i
- Canon T8i / 850D, 24mp
- Sigma 17-70, 17mm @ f/2.8; I'll close down a stop and / or rack in to ~22mm if necessary, but not unless needed
- Typical night time temps are upper 70s / lower 80s F right now
- I plan on eventually stacking, flats, bias, etc. I realize there'll be lots of mistakes along the way, but that's the direction.
I took some static test shots from my Bortle ~6 patio back in January just to see noise vs. ISO, but that's a lot different. ISO 1200 - 1600 looked not too bad on 15 second exposures, IIRC, but they weren't stacked. Where I'll be shooting might be Bortle 4 to the ENE, brighter elsewhere.
The T8i is relatively clean (but it's hot out) so I have no idea whether to start at ISO 800, 1200, whether to expose for 10, 30, 120, 300 seconds, etc. I know there'll be trial and error, but I probably won't be able to tell much at all until the images are stacked (i.e., not in the field). I'd like to avoid being initially so far off I can't tell what's happening.
Taking trailing out of consideration, does anyone have a rough starting point?