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Old 11-02-2011, 03:16 AM
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pmrid (Peter)
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Vertical streaking - what is causing please

I grabbed an hour of clear this morning and grabbed 8 or so 2 minute subs of NGC5128 with an EdgeHD1400 at F11 (yep - still waiting to get the reducer working) - captured with a Canon 1000D at 800 ISO. Lights and Darks only.
Stacked in DSS and basic curves and levels in PS3.
I attach a crop of the core of the galaxy and you'll see the strong vertical streaking all through the image. OK there is probably an issue with either guiding or camera alignment as well (see slightly eggy stars) but put that aside. Where did those streaks come from.
I noted later that although I set Raw+L in the camara, thise settings were over-ridden by the plan I used in APT so in the end the images were all just JPEGS not RAWs, but would that alone expl;ain the streaks?

Peter
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Old 11-02-2011, 05:41 AM
gbeal
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I reckon it is in the stacking to be honest Peter, do the single subs show this same streaking, or is it just when you stack them?
Gary
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Old 11-02-2011, 08:39 AM
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pmrid (Peter)
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Quote:
Originally Posted by gbeal View Post
I reckon it is in the stacking to be honest Peter, do the single subs show this same streaking, or is it just when you stack them?
Gary
Hi Gary. I suppose it must be. I've tried different combinations of subs in stacking, even single subs. But the streaks remain. I'm stacking JPEGs of course, and this is going to increase the problem.
Sometime next year, when we get the next clear night, I'll try to remember to have another crack at it.
What do you think about the eggy stars? Collimation, guiding, camera alignment?
Peter
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Old 11-02-2011, 08:45 AM
gbeal
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Don't accept my suggestion Peter, I could be well wide of the mark, wait for some other clever fellas to chime in.
I reckon guiding (you did guide, yes??), if it were collimation or camera alignment it would likely be worse one side than the other.
Gary
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Old 11-02-2011, 09:59 AM
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pmrid (Peter)
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Quote:
Originally Posted by gbeal View Post
Don't accept my suggestion Peter, I could be well wide of the mark, wait for some other clever fellas to chime in.
I reckon guiding (you did guide, yes??), if it were collimation or camera alignment it would likely be worse one side than the other.
Gary
Guiding, yes, but at a FL of 3550, guiding is going to be delicate at best. My Guidescope is a 100mm Ed with a FL of 600 so it's not too shabby. But the seeing was only mediocre so I had PHD doing 3 second shots. Maybe I should have pushed it a bit harder. Who knows? It's just so frustrating to have so little clear sky to allow you to experiment and tweak these settings.

But I know I'm whingeing to the converted.

Peter
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