DBE and diffuse nebula - Tadpole nebula?

[magnusl]

Hi!

I've been taking a number of subs of the Tadpole nebula, and in trying to process it am beginning to run into some challenges - first with DBE.

I'm using a DSLR- Canon 350D - with a C8. THis means that the nebula fills a lot of my subs. And it is faint and diffuse. What does this mean for DEB? There seems to be a significant risk that I include the nebula in this, and thus remove what I wish to keep and enhance. Is there any way to handle things like these? Or should I not use DBE at all with objects like this?

I've uploaded a calibrated light sub in a dropbox folder:
https://www.dropbox.com/sh/fs744ujp8oed79d/AACfnztnt-E98N8km8Tv2dUBa?dl=0

Any suggestions warmly welcome.

Magnus

[Geoff]

I've found that when there is a lot of nebulosity around, ABE may work better than DBE. Often the background model in ABE seems more reasonable than that of DBE
Geoff

[aworonow]

There are cases when the neb just covers everything and background extraction is not really possible to extract a background. But, otherwise, a few well-placed points on anything looking like background may work because the algorithms fit a low-order surface to the field, and higher frequency patches of nebula may "rise above" that gentle background.

Also, play with the geometry tools at the top of DBE. If you are sure you have vignetting symmetrically about some point, finding one background point and specifying that the geometry (where similar points would be, were the not obscured by nebula), may give adequate results.

Alex