Quote:
Originally Posted by Sarge
James,
From my very limited experience, high ISO will create noise. If your able to guide - longer exposures at a lower ISO say around 800 will produce more data for better results.
Saying that I like your second attempt, well done.
Clear skies
Rod
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Agree - ALL my imaging is done at 500 ISO or 800 ISO. 500 for the brighter stuff, 800 for the dimmer stuff. I WILL push it to 1600 if the object is INCREDIBLY faint, but then you get all sorts of noise issues - I have found even with a full set of flats, dark flats, bias and darks that at 1600 the stacking programs still leave a lot of residual noise that it cannot differentiate from stars - so, if shooting 1600, I will turn in-camera long exposure noise reduction ON, and live with fewer subs. This helps further in post-shot noise reduction in DSS.
ALL my subs are either 5 or 10 minutes, NOTHING shorter. I need to with a 4" refractor
Also, possibly consider PRE-PROCESSING some subs - put them into a RAW editor and edit as far as possible, especially noise reduction (Photoshops "Reduce Noise" filter in CS5 and later works really well, as does Nik's DFine plugin), THEN stack them - you'll be amazed at the resulting differences.
And don't forget the golden rule - NEVER STACK JPEG's - absolute waste of time. JPEG's are VERY lossy files in terms of detail mapping etc. Stack RAW, TIFF or FIT only (strangely I have had issues stacking TIFF's - cannot explain why - get rotational effects, whereas the exact same RAW's stacked do NOT)