M42 before the clouds rolled in

[Whitters]

Nice one Chris

[Whitters]

Fay, are you adding your FR to the scope at the beginning of your imaging session or half way through? If you are adding it half way through have you let it cool down or brought it direct from the house?
The Lock 'n Lock containers are great for keeping the dew off while eyepices and filters etc are not in use. See Lakeland Plastics.

[Fay]

IT is put on a the beginning of a session, Paul. I notice it when used with the Canon. I will keep an eye on it, & suss out under which conditions I am getting a problem.

[Rocket Pooch]

ok when i said the image needs flats, have a look at this

[RobertM]

See what you mean!  Any idea what that dark stripe is down the left hand side - I get something similar across one of the longer sides...

[Fay]

I have a dark stripe on the left side when using the Atik. 

[Rocket Pooch]

Yes its just that the chip ADU's are less there thats all there is about 120ADU difference between the strip and the rest of the image.  Not a problem, you will see on the image with the nebula stars are still there.

Fay don't worry about the strip you can get rid of it as you can see on my processed image.

The key point for me is here in sunny mottingham I have to do flats and flat darks because the signal to noise is allways bad, think about it M42 has to be the brightest object there and its an issue

Nere is a BIAS for the camera, you can see the difference, but remember the ADU difference is 140, this equates to 0.2% flatness of field at full well depth, so you would never see it if the image is very bright.  However if the image is only 2,000 ADU as most of mine from here are then its 7% of the image and is bloody anoying, hence the need for BIAS frames.  Flats are similar in theory.

[Fay]

Your M42 is turining out very nice Chris. I like to see how it gets better as you continue the processing.

[Rocket Pooch]

ok will put a note up here somewhere, if there was somwhere I could be seen, maybe an image processing page Ian?

[Ian]

we bandied around this idea a while back, and I think Rick had a bit of a cogitate about it. There's lots of really useful technical detail locked up in the forum, but there's no easy way to access it other than working with the search. I still quite like the idea of a Wiki, but Rick's not a fan due to the administration overhead. Lets have a chat about it in the pub next time.