NGC 6992 the Veil Nebula

Hi all,

Here is an image of NGC 6992- The Veil Nebula. I don’t have any colour for this image yet hoping to get some clear nights in August to finish it. The image is 7.5 hours total exposures where 90x 5min subs using a 6nm 50mm round H-Alpha filter; Darks where 50x5 min and flats where taken at 32000 ADU. Through a Williams Optics 110mm scope with an Atik 4meg CCD. All Processing was done in Photoshop CS3; NGC 6992, The Veil Nebula is an expanding gas cloud remnant of a supernova. The supernova happened about 30 to 40,000 years ago and is roughly 70 light years in diameter. This nebula is a radio source, but not as strong as the much younger Crab Nebula. It is thought that the gas in the Crab Nebula will eventually spread out and resemble the Veil Nebula in 20,000 years or so. I’m looking forward to seeing that.

Please click on the image to enlarge,

www.webtreatz.com/gallery/displayimage.php?pos=-130

Carl.

awesome shot there Carl, :bigshock:
I'll be setting this as my new wallpaper on the pc if thats ok with you.

Dave_Lillis wrote: awesome shot there Carl, :bigshock:
I'll be setting this as my new wallpaper on the pc if thats ok with you.

Hi Dave,

Thanks for the feedback. You are more than welcome to use the image :>)).

Carl.

Carl - I see you used 50 darks. I'd normally not bother with more than 20.

So, I got to wondering, what is the general wisdom out there as regards the number of darks to use for calibration? And for an additional bonus point, what would the number be for flats.

Nice image by the way - I've seen many colour shots but there is something appealing about monochrome.

Cheers
Dave

dmcdona wrote: Carl - I see you used 50 darks. I'd normally not bother with more than 20.

So, I got to wondering, what is the general wisdom out there as regards the number of darks to use for calibration? And for an additional bonus point, what would the number be for flats.

Nice image by the way - I've seen many colour shots but there is something appealing about monochrome.

Cheers
Dave

Hi Dave,

I remember having a chat with some imagers and they tend to use 50% less darks of their total luminance frames to get a better model for the noise in an image. This will also tend to cancel out any slight variations in temperature between the images. But 20 to 30 is also good enough depending on what camera you use; as for the flats I use around 15 at just below 1/2 my CCD sensitively of 65000 ADU but I could go down to 26000 ADU
Here is a great link for anyone doing astrophotography with a CCD or DSLR camera starizona.com/acb/ccd/procbasicintro.aspx

Thanks for the feedback Dave.
Carl

That's a fine image Carl.
The Veil is one of my favourites
Great detail.

One small comment:
Is it me or does it look better rotated 90degrees anti-clockwise?
Or mabey that's just how I am used to seeing it.
Just wondering....