Untried filter

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bchamberlain
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Untried filter

Post by bchamberlain » Sun Aug 25, 2019 10:59 am

Last night was my 1st imaging session since April & 1st try of a CLS-CCD clip filter. The BG in iris reads 2820 which seems a bit high.
Three hours so far and hopefully add to it tonight or Monday to pick up the faint galaxy cluster adjacent to NGC 7331. Bill C

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rwilkinson
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Re: Untried filter

Post by rwilkinson » Mon Aug 26, 2019 8:52 am

bchamberlain wrote:
Sun Aug 25, 2019 10:59 am
The BG in iris reads 2820 which seems a bit high.
Could that be just down to the high ambient temperature?
My imaging session on Saturday night produced a number of hot-pixels from my Mx716 camera which I hadn't seen before!

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bchamberlain
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Re: Untried filter

Post by bchamberlain » Tue Aug 27, 2019 8:24 pm

Could be Ross. Anyway, Partly processed (40 x 600s) and looking promising.

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Re: Untried filter

Post by bchamberlain » Sun Sep 01, 2019 8:48 pm

I'm getting strange results with this filter. With 'Normalise if overflow' ticked I get detail in the three channels and although the numbers in G & B are triple the Red i.e. 579, 1513, 1503, it's still manageable, but with 'Normalise if overflow' unticked RGB is 15042, 32767, 32767 with no detail whatsoever in the G & B channels. The unticked file is unusable. Anyone know what's going on?

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Re: Untried filter

Post by rwilkinson » Tue Sep 03, 2019 1:04 pm

IRIS uses "signed 16-bit" numbers, i.e. between -32726 and +32767. so you're saturating in the G & B channels.
So you must use the "Normalise" process: this automatically re-scales the totals to prevent saturation.

And you could try boosting the Red channel using the RGB Balance panel, or the >RGBBALANCE command.

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bchamberlain
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Re: Untried filter

Post by bchamberlain » Tue Sep 03, 2019 2:39 pm

Thanks Ross. Unticking the normalise is definitely out with this filter as the detail in the G & B channels is completely blown out. I'm playing about with the balance in the ticked file and finding the green chanel far too dominant. I think it's back to the UHC filter.

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