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Originally Posted by tornado33
Thanks for the comments all
This is the first image where I didnt use Gradient xterminator, rather I use a flat field (only one), to experiment how Iris goes with that method. Also I was using a crude cardboard dewshield about a foot long, to try and keep out stray light from the side. The xtra spike might be the metal frame holding the first pickoff prism for the off axis guider. The prism are quite large, making locating guidestars a snap, its easier to locate a guidestar now than with my old 75mm guidescope in guidescope rings.
Ive still a way to go to get fully 100% flat background images. Also, my dad has offered to drive me to Sydney one day to drop off my 10 inch "Sutching" mirror for aluminization (I simply cant bring myself to trust it to courier no matter how well its packed).
The scope I use is a 10 inch F5.6 Newtonian, on a "Sampson" GEM mount
http://www.users.on.net/~josiah/focuser/IMG_9932.jpg
Rough paintjob as u can see lol |
Hi Scott,
I know it was just an experiment, but you do need to be careful using only a single flat. Any noise in the flat will be transfered to your light frames when they are applied.
Taking several flats and averaging them to create a master flat will minimise this problem. I usually use about a dozen.
There is also an artifact in the centre of the image. It looks like a very large dust donut. It could also be a problem with your mirror if you say it needs to be redone. Another cause may be a problem with your flat.
Gee I sound picky tonight. Must be the clouds.
Cheers