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Old 25-07-2018, 01:55 PM
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Stonius (Markus)
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First light on DSO for OAG, OMG what am I doing?

So I did this the other night shortly after I shot the Mars photo I posted in the other thread. As mentioned, it was blowing a gale - so much so that my plans to try and get the hang of PHD2 went awry because it kept losing the guide star during calibration. That could be me doing something wrong though. So I *think this is an unguided pic, despite the OAG setup (exposures were short anyway). Still it was good to go through the motions. The point was to get some data to play with, so I'm pleased to have anything at all.

One of the issues I had was the shadow along the top edge. I assume this was a prism shadow? I guess I need to back it off a bit?

Also the DynamicBackgroundExtraction Process in Pixinsight made things a lot worse for me (I've been following the Light Vortex Tutorials). It seemed to remove the background in a very uneven way. Not sure if that was due to my sample placement or due to noise in the image, or what, so I stuck with the gradients because the end result was better for the time being.

Anyway, this is the result of 20 x 30 sec LRGB exposures shot from light polluted Melbourne. For the more experienced dudes - is this pretty much the result you'd expect from a 10" RC operating at around F5.36 with an ASI 1600?

Looking at it now, maybe I've burned out the stars a little too much while trying to bring out the dimmer ones, I guess.

I realise many wouldn't bother shooting the luminance channel on this target, but I'm glad I did because I wanted to play with the luminance data, and besides, it disguised a multitude of sins in the RGB combination image caused by differential gradients that I am not yet skilled enough to rid myself of.

Thanks for looking and for any comments - I'm very much in need of guidance at this stage (no pun intended) :-).

This is the full frame, ie, the full ugly - only cropped to remove the black edges from channel combination.

Markus
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Old 25-07-2018, 04:26 PM
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Anth10 (Anthony M)
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Hi Stonius,
Looks good- great stuff.
My two cents worth would be to try lowering your ISO setting to get more star colour and this would also help keep the core from over exposure.
I have found that using a LP filter helps for the burbs too.

Good luck with your setup

Anth
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Old 25-07-2018, 04:39 PM
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Stonius (Markus)
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Oops, I should have mentioned - I was at gain 200, IIRC. Yes, I figure if I was doing this target *properly, rather than just gathering some data to play with I'd be looking at maybe 2-3 hours total integration time to do it justice.

How do you combine your LP filter with your filter wheel? where abouts in your imaging chain does it fit? Does it increase exposure times by much?

Cheers M
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Old 25-07-2018, 07:01 PM
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Anth10 (Anthony M)
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One hour will give you a respectable result. I don’t use a filter wheel so not sure, I use a dslr with adaptor at prime focus. My filters just screw in on the back of the threaded barrel.
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