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need help Monochrome OR Color CCD


doseri

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Absolutely agree with this although I don't like MaxIm DL's (my preferred software) results with these and I use Nebulosity if I am using this approach. With 'dithering', I still find Dark frames very effective with my QSI 683 mono CCD camera even with auto exposure compensation in use if I don't have a matching dark frame set in my regularly updated 'library'.

Sent from my iPhone from somewhere dark .....

DIthering's good if you can do it but with a dual rig it's difficult. Still, my thinking is that blending two cameras' images has a similar effect in that the residual random noise is stirred around.

Olly

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DIthering's good if you can do it but with a dual rig it's difficult. Still, my thinking is that blending two cameras' images has a similar effect in that the residual random noise is stirred around.

Olly

It is probably similar to imaging on both sides of the maridian. I almost always find images where I 'flipped' are less noisy that images that were all from the same side.

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It is probably similar to imaging on both sides of the maridian. I almost always find images where I 'flipped' are less noisy that images that were all from the same side.

That's an interesting point that I hadn't considered before.

DIthering's good if you can do it but with a dual rig it's difficult.

Good point - introducing artificial diffraction spikes I can understand in some circumstances but introducing jagged star trails is just so wrong! :grin:

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Two on one mount? But presumably you'd need to use the same sub lengths in both?

Olly

Yes but you can sync the start times for the sub capture, if your goign to do mixed sib lenghts its not goign to to be possible. unless i guesss they sync and one sits idle whiel the other finishes, im not sre im still resarching it :)

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Another reason why im looking at maxim now as it supports two scopes and dithering.

Not really.. at least not the last time I tried it in V5 last year. To my disappointment when I quieried this on the Maxim forum & with Bob at ACP, I was told only support for one imaging camera.  Not looked at it again in V6 but the second camera is expected to be a guide cam. I haven't noticed any change to the camera setup in V6.

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Is there any review on baader LRGB

I don't know of one but my stuff is here. http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/22435624_WLMPTM#!i=2266922474&k=Sc3kgzc

When I tried the Astrodon RGB I found the blues a bit 'funny.' AD stress that theirs is a teal blue. Personally I didn't feel at home with it but that could be lack of familiarity. Plenty of big hitters use the Astrodons, of course.

Olly

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Is it not possible to put a LP filter onto a OSC CCD?

Sorry I have no experiance of these cameras and whilst reading this thread people were recommending Mono CCD's as they have less issue with LP due to the NB filters used.

Apologies if I have just ruined a intelligent discussion with a noob question.

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Is it not possible to put a LP filter onto a OSC CCD?

Sorry I have no experiance of these cameras and whilst reading this thread people were recommending Mono CCD's as they have less issue with LP due to the NB filters used.

Apologies if I have just ruined a intelligent discussion with a noob question.

You can use an LP filter on a colour camera and people do so. This is a perfectly sensible question, fear not!

However, narrowband imaging (using filters which isolate very specific emission lines like H alpha, OIII, SII, H beta...) is a different kind of imaging and is vastly more effective against LP than any LP filter. The result does not normally give a natural colour image so much as a colour map or false colour image. While these filters can be used with varying success on an OSC camera it is not a good idea in principle. Ha, for instance, is a narrow slice out of red so the OSC's blue and green filters block it, meaning that only a quarter of the pixels seen any Ha. O111 is an emission line on the blue-green border so it's blocked by the red filters and, to some extent, diminished by the blue and green - I think. Not sure about that. The logical choice for narrowband imaging is the monochrome chip in which all of the pixels see all of the narrowband filtered light.

Olly

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Is it not possible to put a LP filter onto a OSC CCD?

Sorry I have no experiance of these cameras and whilst reading this thread people were recommending Mono CCD's as they have less issue with LP due to the NB filters used.

Apologies if I have just ruined a intelligent discussion with a noob question.

Mono CCDs have as much issues with LP as does an OSC if LRGB imaging is used. You can put a LP filter on an OSC camera and infact this is a must in a LP zone. In case of a mono CCD onlly the NB filters in particular the ones with a very narrow passband are immune to LP to a large degree. This is one of the reasons that an OSC camera still does well particulaly in a heavy LP zone. For an efficient LRGB imaging true dark sky is a must if the use of a LP filter in front of RGB filters is to be avoided, LP filter is not strictly necessary with NB imaging.

A.G

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