Strange image artifacts

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Paleblueastro
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Strange image artifacts

Post by Paleblueastro »

I've been perusing this forum for a few months now after getting in to solar imaging, I've been doing deepsky for a few years and wanted to extend the hobby into daylight, I use a 152mm F5 Acro with a quark stopped down to 90mm to reach F/35 and a ZWO tilt adapter on a QHY5III174M to image, I've gotten a few promising results so far but my last couple sessions I've noticed some weirdness creeping into my images, I seem to have a partial region that looks maybe off band? Or something? It appears brighter than the rest of the image, and looses all the nice Ha detail, the weird part is it rotates around WITH the camera, so if I loosen off the set screw on the camera only and rotate it this aberration rotates with it the rest of the imaging train remains unchanged has anyone come across this before? Luckily if it's the camera it's brand new so still under warranty
The region in question is circled
The region in question is circled
2021-06-01-2336_7_lapl4_ap4068_processed.png (957.85 KiB) Viewed 250 times
AR2827.png
AR2827.png (1.16 MiB) Viewed 250 times


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marktownley
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Re: Strange image artifacts

Post by marktownley »

Hi There.

Welcome to the forum!

Sorry to be the bearer of bad news but this is (another) example of poor quality unevenly illuminated Quarks. There's nothing you can do to fix it, maybe return it to where you got it from and try and see if you can get a better replacement?

Mark


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yltansg
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Re: Strange image artifacts

Post by yltansg »

Hi Paleblueastro,

Like what Mark said, it is probably due to an unevenly illuminated Quark.

The interesting thing is you mentioned "it rotates around WITH the camera". Does that mean that, if you keep the Quark still and rotate the camera, the part that has lesser details can begin to show the details?

Alfred


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minhlead
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Re: Strange image artifacts

Post by minhlead »

Like Mark and alfred said, it's ununiformity in the etalon of then Quark and you can not do anything about it. You can do a tuning test (by turning the knob), take a series of photos and then comparing them. Knob tuning will decrease/increase or shift the sweet-region. Base on your image, i think you can savalge some sweet-region by turning the camera so the out of band area stay on the short side of the camera so you'll get more on band area fall on the sensor.
I have a bad uniformity quark too and tuning it to have the largest sweet region possible, combined with ROI cropping help me achieve okay result. Learn to live with what you have since exchanging a Quark based on uniformity reason typically not accepted by Daystar
You can see my post on tuning my quark here.
viewtopic.php?f=4&t=31710&start=25


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Paleblueastro
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Re: Strange image artifacts

Post by Paleblueastro »

Thanks for the feed back everyone! I'll try tuning it again and see if I can increase that sweet spot size, I only noticed this started happening after my last session, this quark is out of a solar scout and I had taken it from my big frac and put it back into the little 60mm one for a day of messing around and had retuned it so hopefully I can get it back to working in this one.


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Re: Strange image artifacts

Post by marktownley »

Sounds like it could be tilt somewhere, this could cause it...


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