Quote:
Originally Posted by Merlin66
Looking good!!
I'd be interested in your set up.
Which telescope?
What distance between the SA and the CCD chip?
You seem to be able to get down below 400nm which is very good.
I'm just struggling a bit so far down in the UV. My "trials" with a 80mm cemented doublet definately showed you didn't need a UV-IR filter! The lens does it for you! I made the mistake of trying to use the Canon ( convenience!) and wondered what was going wrong.
The Canon is no good, drops to about 10%, the MX7c & DSI II are just below 40-50% efficient, the QHY5 drops to 30%, the webcam's are below 20% and the best so far are the Atik16ic at around 60% and the DMK21 at 50%
Keep it up; you're getting some good results!!!
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Thanks
I haven't measured the distance from the SA to the CCD- not that easy to do. The SA is in a filter wheel and the CCD cameras don't have the position of the CCD on the outside.
The scope is a VC200L. This has no corrector plate but does have a correcting lens in the draw tube.
My Genesis/Audine camera does have a very old UV filter as it's front glass but it obviously doesn't block the deep violet very well.
The kodak chips in my 2 cameras are both "E" chips that are suppose to have an improved blue response but they are still much more responsive in the red. I have found doing photometry with a blue filter that I need about 2x the exposure in blue for a similar flux compared to a V filter. The red needs 2/3 the exposure of the V and IR is about the same as the V filter.
I haven't tried a colour camera yet but might give it a go with my 40D.