Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: Daniel on Jul 28, 2009, 17:47:57

Title: M17 The Swan Nebula 32x60s ISO 320
Post by: Daniel on Jul 28, 2009, 17:47:57
Hi All, Did a quick test on this low object, which I never thought I could get until managing the Trifid the other day, the seeing and cloud wasn't too great and I only had a very limited amount of time since I had to be up early this morning so the collimation wasn't 100%.

One question, how does this look on your monitors, It looks fine on my laptop and the black point is set around 20-22 but I've just copied this over to my work computer and it looks incredibly dark, looks awful.

Daniel
:O)

(http://farm4.static.flickr.com/3249/3766333836_1f3c43e14b_o.jpg)
Title: Re: M17 The Swan Nebula 32x60s ISO 320
Post by: RobertM on Jul 28, 2009, 20:22:56
Black looks a bit too black for my tastes but not awful.  It's mostly ok for galaxies as the interstellar medium is very thin and generally black anyway but in the heart of  the milky way there be nebulosity everywhere.  I personally would lighten the background and apply some low level NR also there is a but too much colour in the stars (brighter are nearly all blue and fainter all red).  Having said all that, the Swan looks like a very tricky target and you've captured it very very well.  I would be more than pleased with that result, I hope you are too?
Title: Re: M17 The Swan Nebula 32x60s ISO 320
Post by: Ian on Jul 28, 2009, 20:30:10
definitely has an odd colour balance but hey, it's better than my effort. That was obscured by the inside of the shed roof...
Title: Re: M17 The Swan Nebula 32x60s ISO 320
Post by: Daniel on Jul 28, 2009, 20:37:15
Thanks guy's, the colour will be my over zealous use of Noel's increase star colour action, shall sort that in a re-process as Im on my way home on the boat tonight, just wondering what background rgb values you guys tend to use for space?

Daniel
:O)
Title: Re: M17 The Swan Nebula 32x60s ISO 320
Post by: RobertM on Jul 28, 2009, 22:11:46
Daniel, can't you ask easy questions !  I actually cheat and use one of MaximDLs equilisation options to balance the background colour for me (works in most cases).  I could also choose a star to use as a white balance but I've never managed to find a star that's balance is white!  It's a very tricky question, you should take a non saturated image of a G2V star to obtain the required balance.  That will give you the values you're looking for, here's a link to some more info and a list of stars if you're interested:

http://www.kellysky.net/artdraf7.htm (http://www.kellysky.net/artdraf7.htm)

http://www.gemini.edu/sciops/instruments/nir/specstandards/G2V.html (http://www.gemini.edu/sciops/instruments/nir/specstandards/G2V.html)

Hope that helps
Robert