Helix - Weak signal recovery, see Nothing at 1st

[PETER LOO]

Helix Nebula has a low surface brightness and therefore is a relatively challenging object or weak signal unlike bright nebula like Orion Neb, Eta Carina etc.
Need to collect as much light frames at the longest attainable exposure time, stretch each subs & then combined them together (using 2013 Aug data here)

My personal preference is to capture the sub exposures with MaximDL Raw to Disk mode which preserved the original vendor (eg. Canon) CR2 format, then use the Canon supplied s/w to convert them to TIFF file instead of using other way to convert color, so far, this method seems to yield least lost and best color conversion.

Helix before stretch J by Astro shots & stuff, on Flickr

Helix after stretch by Astro shots & stuff, on Flickr

Helix 31 Aug 2013 combined by Astro shots & stuff, on Flickr

[Mariner]

It can be barely discerned in the orginal.

[PETER LOO]

Thanks Mariner, yah, a lot of difference after combining the sub-exposures. "Screen stretch" of individual sub may not be useful unlike a "Log stretch". For a wide dynamic range object such as Andromeda Galaxy performing "Log Stretch" to each subs before combining them will definitely bring out more details on the Galaxy's spiral arm.