How early in evening to start NB imaging

[nigelbeaumont]

I normally wait until the start of astronomical dark to start imaging, which is about 2200 at the moment where I live. However could I start earlier in the evening if I'm narrowband imaging, say about 2100? It would gain me an extra hour at a sensible weekday time for the longer NB subs

[wuthton]

My sunset is probably similar to yours. The following Ha subs were taken last Sunday, the first at 9.10pm and the second at about 11pm.

9.10pm

11pm

The basic image analysis in SGP does give a higher star count for the second image and close inspection does reveal it to be superior but the first sub is not time wasted in my opinion.

[laudropb]

Very nice comparison. I suppose it depends on what you hope to achieve.