Deeper Horsehead area 3.6 hours with 300mm lens

[tornado33]

Hi all
last night I did a rather long imaging run on the Horsehead area. It included a meridian flip.
Its 22 x 10 mins ISO400, with modded 350D. Baader UHC-S and IDAS UV/IR filters used, in back of the 300mm F2.8 lens from Bert, with f4 aperature stop fitted to the front.

The hassle was not light pollution, but rather thermal noise, the ambient temp started at around 30 degrees and was still 25 near the end at about 2 am.

After several goes at calibration, Iris seemed to do the best job at handling the thermal noise, which reall was bad. Ive attached a crop of one sub.

Full sized version of image here (http://d1355990.i49.quadrahosting.com.au/Scott/horsehead22x10minsiso400uvirmod350d 300mmf4irissmstsbdarkerb.jpg)
Scott

[CoolhandJo]

Thats a lot of noise in that single sub! The end result is nice. You have processed out a lot of the nosie well.

[wasyoungonce]

A great end result though...well worth it.

[Hagar]

Nice result Scott for such a noisy single sub frame. You seem to have a few reflections there to tame as well.

[Garyh]

Boy, what noise! That would be hard to tame!
You managed to get quiet deep in the final image but.
:thumbsup:

[tornado33]

Thanks all
The 2 filters seem to cause some reflections between each other. If I use the LPS filter, as it blocks IR as well, a separate uv/ir filter is not necessary. I think that was the hottest night Ive ever done DSLR astro imaging on.
Scott