Very clear skies with almost no cloud cover. Got some great images looking back over the house which I've not tried before. Also experimented a little more with various ISO settings with the same composition as well as wider range of exposure times.

Gear:

• Canon EOS 200D
• Tokina AT-X Pro SD 11-16mm f/2.8 (IF) DX
• Tripod

Weather:

• Very clear

Location:

• Garden

Software

• Rawtherapee - RAW file importing, optical correction & image processing
• GIMP - RAW/TIF to JPEG, cropping

These first three images are tests of different exposure lengths, all at the same 800 ISO setting. At 20 seconds the image is relatively clear (though with a relatively modest amount of noise, as expected with a single exposure) with most objects well defined and without trails:

Fig. 1: 20s, ISO 800, Processed RAW Fig. 1: 20s, ISO 800, Unprocessed JPEG

At 25 seconds some objects are starting to elongate slightly:

Fig. 1: 25s, ISO 800, Processed RAW Fig. 1: 25s, ISO 800, Unprocessed JPEG

At 30 seconds, I start to get very distinct stair trails forming:

Fig. 1: 30s, ISO 800, Processed RAW Fig. 1: 30s, ISO 800, Unprocessed JPEG