M27 Dumbell Nebula 15.7.13

Only managed 160 mins on this as fell asleep at the wheel and missed the flip! Too many late nights the last couple of weeks....

Gareth - that's a pretty good shot. Any details of your setup and the cal frames you used?

I suspect flat-fielding might improve the image since the background seems (on my displays) to be a bit dark in the central portion and a fair bit lighter in the outer regions.

That said, I'm not familiar enough with nebula - perhaps that is the way it is.

Thanks for sharing!

Yea, I had noticed that myself as well but couldn't figure out what it was. I'm currently having some issues in Nebulosity getting my exposures with my flat panel down to the correct ADU so this has no flats. I gave it a couple of passes with Gradient Xterminator and it still showed up. The image is actually a crop of a much wider FOV so doubt it's a vignetting issue.

Will have a play around with the data and see if I can do anything with it - thanks for the feedback by the way

Gareth

Restacked everything with some flats from another night, I know that I shouldn't really do that but it definitely helped smooth things out I think

Gareth - that is so much better - well done.

Flats need only be taken periodically. So it's perfectly acceptable to re-use them. The triggers for retaking them would include significant changes to the optical system (e.g. introduction or removal of field flattener) or if you're finding new dust donuts appearing.

Darks can be used the same way if you have a cooled camera (build up a library of darks for specific temperatures and durations then shoot at those times/temperatures).

I'd take new darks maybe evry one to two months. I keep reusing my flats until the new dust donuts impinge too much.

Hope that helps...

Gareth,

I've seen so many images of this nebula where the nebulosity drowns out the stars in the central area, to even losing the main central star which is the important star for this PN.
Your image shows these stars well and even the surrounding stars.

Thanks
Eamonn