Widefield Crux and Centaurus

[tornado33]

Was windy but very dark and chilly last night, perfect for widefield with the 50mm f1.8 lens.
Crux area, 50mm f5.6, 3x10 mins ISO400
Full size version here
http://d1355990.i49.quadrahosting.com.au/Scott/crux3x10minsiso400astronomikuvir350 d50mmf5.6x14deg.jpg

Centaurus area, 2x10 mins f5.6.
full size here
http://d1355990.i49.quadrahosting.com.au/Scott/centaurus2x10minsiso400astronomikuv irmod350d50mmf5.614deg.jpg

Both shots used an astronomik UV/IR filter in front of lens. Modded 350D hand guided.
To get pin sharpstars I took test pics at f1.8 till stars were pinpoint then stopped down. I also guided as accurately as if I was imaging with the 6 inch scope.
Scott

[RickS]

Very nice! What camera did you use?

Cheers,
Rick.

[Lester]

Very nice view Scott.

[jjjnettie]

:) See, Emu's can fly.

[h0ughy]

great work Scotty

[madbadgalaxyman]

Hi, tornado33,
In your photo, I enjoyed the sense of the dust in the Coalsack being not particularly heavy in its extinction of the background light.

A couple of papers that I once read found that even the most dense parts of the Coalsack only decrease the light of the background stars by a visual extinction of only 2 to 2.5 magnitudes.
In fact, Seidensticker and Schmidt-Kaler (1989, A&A, Volume 225, p.192) found that the average visual extinction ("dimming") caused by the dust within the Coalsack is only 0.94 magnitudes!!!

note added in edit:
I just downloaded a recent paper stating that there are a few very small spots in the Coalsack where visual extinction is 6 magnitudes, while not changing the overall picture of modest extinction for most of this dark nebula.

[madbadgalaxyman]

Further to previous message, here is the Seidensticker and Schmidt-Kaler map of how extinction varies over the face of the Coalsack. (some recent authors find slightly higher values.)
This is essentially the dimming of background light, at an observation wavelength approximating visual observation.

115167


I might continue this cogitation about the Coalsack in the Science Forum!!

Note added in later edit:
Yes, bad galaxy man continues this discussion of extinction in the Coalsack, in the Science Forum!!!

[tornado33]

Thanks all
I used a Hutech modded 350D camera with chear glass AR coated cover over sensor option.
Scott