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Post by ChrisV on Aug 28, 2017 13:03:00 GMT
Did a short broadcast tonight, for an hour or so before the clouds came in. ASI290MM on 80mm refractor. Trying out a baader 8nm H-alpha filter. Used sharpcap alone. First up Swan nebula. Just UV/IR filter 24x 10sec, 240sec total. Then with the H-alpha filter. 8x 30sec, 240sec total. Needed longer subs. But this is with the same total exposure.
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Post by ChrisV on Aug 28, 2017 13:07:25 GMT
Lagoon nebula. Just UV/IR filter 17x 17.5sec, 127sec total. Then with the H-alpha filter. 6x 30sec, 180sec total.
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Post by ChrisV on Aug 28, 2017 13:10:25 GMT
I also got M16 - a huge stack, but I had to go off and do something so let it run With H-alpha. 20x 30sec, 600sec total Didn't get similar duration without H-alpha. It was a quarter moon up reasonabley high
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Post by Dragon Man on Aug 28, 2017 14:37:16 GMT
Where's the colour? 'nudge nudge'
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Post by ChrisV on Aug 28, 2017 22:13:46 GMT
I'll rip out the crayons
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elpajare
Member
Posts: 438
home town/country: Girona-Spain
time zone gmt +/-: 1
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Post by elpajare on Aug 30, 2017 9:46:48 GMT
I think that 30" is the right speed for this objects. In Ha or in RGB., with this kind of sensors ( IMX290/244....)
My results are the same of you.
My doubt is if this is an additive stacking or another kind of stacking. I never had clear how every software manages stacking.
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Deleted
Deleted Member
Posts: 0
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Post by Deleted on Aug 31, 2017 0:17:14 GMT
Is the H-alpha image better because you've used longer subs or because the background is darker?
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Post by ChrisV on Aug 31, 2017 0:45:20 GMT
I haven't seen your H-alpha images Elpajare. But yes, 30sec seemd like a good sub length. I will try higher gain and lower sub lengths tonight.
Side-by-side I think you can getter a nicer imager with the same total exposure. And as you say, I think its because it obliterates the background. I used longer subs with the H-alpha but tried to go for the same total exposure time.
I'm hopefully broadcasting again tonight with a 65% moon. Will try to be a bit more systematic in the comparison between UV-IF and H-alpha filter. And will try a few different gain/sub length combos. I should actually try to compare with no filter - but I don't the clear filter in my wheel.
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