I am working on figuring out how much exposure time I need for astrophotography.  The answer from my Bortle 7-8 driveway is generally: More.  

Here I’ve got three example to show how adding time adds detail to the images.  In one minute, with a lot of processing, I can get the flame nebula to be barely visible, but the horsehead nebula … might be there, maybe, if you squint and know where to look.  With 155 minutes … like magic … you can see both, but they’re grainy.  Going up to 334 minutes, and the image is getting less grainy.  But more time is still needed to get a really nice picture.

Camera geek info:

• Canon EOS 60D in manual mode, ISO 400, 1 minute exposure
• Williams Optics Zenith Star 73 III APO telescope
• Williams Optics Flat 73A
• SkyTech 2” LPRO-MAX CCD Filter
• iOptron CEM40
• Friendswood, Texas Bortle 7-8 suburban skies

Frames:

• March 3, 2023
  • 155 1 minute lights
  • 20 0.2 second flats
  • 20 0.2 second flat darks
  • 28 1 minute darks
• March 4, 2023
  • 179 1 minute lights
  • 21 0.5 second flats
  • 21 0.5 second flat darks
  • 26 1 minute darks

Processing geek info:

• PixInsight
• StarXterminator
• Generalized Hyperbolic Stretch