A galaxy for a change

With a run of clear(ish) evenings I was in "beat the moon" mode again. I decided to return to NGC 6946 which is a face on galaxy on the borders of Cygnus & Cepheus. I had tried this last year with a fairly poor result so it was worth trying to make an improvement. The transparency was very changeable and never became good but I managed to obtain a set of subs before the moon began washing things out too much. Details: 10" f4.3 Newt. 5x 5 minute + 15x 7minute exposures @ iso1600 with CLS in DSS, CS2 & XAT.


caracol_uk said...

Hi Pete,

Looks like you've been making the most of the clear nights and judging by your images, rather successfully too.

I notice over the past couple of months you've been imaging at ISO1600 rather than ISO 800. Is this just a temporary change, or do you find ISO 1600 produces better results?


P said...

Hi Simon

With trying to keep noise to a minimum I think that stacking 20x 5 minute subs @iso 1600 gives a similar result to stacking 10x 10 minutes @ iso 800. 100% clear nights are a bit of a rarity and more often I find I'm trying to get subs between cloud interference. 10 minute subs are more likely to be ruined than 5s so I now think that shorter subs at higher iso are more productive on balance. On a 100% clear night with good transparency I might revert to iso 800.