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h0ughy
16-04-2010, 11:54 AM
Lession 2 from the doghouse – IC2944

IC2944 – well I now see what a challenge I have from my skies – light pollution kills – as to other fundamental mistakes in the doghouse. Its only 2 odd hours worth of data but the seeing was atrocious and for some reason I focussed in the middle but out of focus at all edges? Go figure? But here is the kicker – I located and took a test shot at iso1600 – but then I forgot to change it back (but I did take raws LOL so no stacked jpegs LOL) I did not realise how bright/dim this object is as I have never before imaged it. I have a WO field flattener/reducer that I might give a go in the image train to work out the kinks. Thought things were going to well when I warm started and found it straight off. Now I have taken this next time I will better position it, lock in iso 400 and do at least 4 hours worth. I must make a flight manual check list for each session to tick off the completed tasks be fore I set to start the run. It’s a horrible image but here it is:

tornado33
16-04-2010, 12:23 PM
Did you use a LPR or UHC filter?, they are the go for handling emission nebulaee in light polluted skies. Also, Paul found that with his refractor the field wasnt 100% flat. Same applies to my 6 inch meade Cometracker SN. I fudge it by getting stars 1/2 way out sharp, that way centre and edges only slightly out.
Scott

JD2439975
16-04-2010, 03:32 PM
Ah yes, forgetting the Hi-ISO test shot setting...I was there just a couple of days ago. :lol:
Left the MPCC on the camera with the ED80 and got "reversed coma" too...oh dear, getting old, time for the glue factory.
Flight style check-list sounds like a damn fine idea to me.

That's not horrible at all, I've seen & done far worse, just the scourge of light pollution that brings it down a notch.

A question for Scott, how do you restore the nebula's colours after using a UHC filter?
I have a Baader UHC but on the times I've tried it I just can't get the colours correct during processing, all purple/grey/green murk. :sadeyes:

Justin

tornado33
16-04-2010, 03:44 PM
Hi Justin
when using IRIS software I draw a small box on some empty space and type in "white" that neutralizes sky background, or else in Photoshop in Levels then set grey point then click on empty space in the image, try it a few times till you get a neutral background
cheers
Scott

JD2439975
16-04-2010, 03:57 PM
Nice one Scott, thanks I'll give it a go. :thumbsup: