What causes this?

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Larry 1969 United States of America
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What causes this?

#1

Post by Larry 1969 »


Every single time I try to image M78 I get this weird artifact. It's happened several times over the past 2 years with different cameras.
Some of you may remember my Silveer Sliver Galaxy image with the line through it even when imaged a few months apart. This is the same but the artifact is different.

Any ideas what could cause this? M78 is a really cool target and I'd like to spend some time on it, but not if I'm going to have to deal with tis every time...

Thiis was 51 x 3 min exposures before moonrise with 50 flats and 50 dark flats.

Thanks!

Larry
Attachments
InkedM78_-RGB-session_1-DeNoiseAI-low-light_LI.jpg
For visual:
10" Skywatcher collapsible goto dob, various EP's and a Celestron StarSense auto align.

For imaging:
Orion 8" astrograph 800mm @ F3.9
Eq6-R Pro controlled by APT via EQmod with an OTA mounted mini PC
Tele Vue Paracorr Type 2 coma corrector
Altair Hypercam 26C
Image
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AstroBee United States of America
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Re: What causes this?

#2

Post by AstroBee »


It looks like reflection from nearby Alnitak. Do you have a dew shield in place to prevent off-axis reflections like this?
Greg M.~ "Ad Astra per Aspera"
Scopes: Celestron EdgeHD14", Explore Scientific ED152CF & ED127 APO's, StellarVue SV70T, Classic Orange-Tube C-8, Lunt 80mm Ha double-stack solar scope.
Mounts: Astro-Physics Mach One, iOptron CEM70EC Mount, iOptron ZEQ25 Mount.
Cameras: ZWO ASI2600mm Pro, ZWO 2600MC Pro, ZWO ASI1600mm
Filters: 36mm Chroma LRGB & 3nm Ha, OIII, SII, L-Pro, L-eXtreme
Eyepieces: 27mm TeleVue Panoptic, 4mm TeleVue Radian, Explore Scientific 82° 30mm, 6.7mm , Baader 13mm Hyperion, Explore Scientific 70° 10mm, 15mm, 20mm, Meade 8.8mm UWA
Software: N.I.N.A., SharpCapPro, PixInsight, PhotoShop CC, Phd2, Stellarium
https://www.nevadadesertskies.com
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Larry 1969 United States of America
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Re: What causes this?

#3

Post by Larry 1969 »


AstroBee wrote: Tue Feb 22, 2022 3:52 am It looks like reflection from nearby Alnitak. Do you have a dew shield in place to prevent off-axis reflections like this?
I do have a dew shield in place. Maybe I could fashion a longer one and try again.
Thanks for the suggestion!

Larry
For visual:
10" Skywatcher collapsible goto dob, various EP's and a Celestron StarSense auto align.

For imaging:
Orion 8" astrograph 800mm @ F3.9
Eq6-R Pro controlled by APT via EQmod with an OTA mounted mini PC
Tele Vue Paracorr Type 2 coma corrector
Altair Hypercam 26C
Image
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Re: What causes this?

#4

Post by Larry 1969 »


I took this on the same night with the same calibration frames but the moon had risen and was a player.
The moon was 80% or so and I suspect it is responsible for my rather poor flats correction, but that glaring artifact is not present.
This makes me think there is something in the sky causing it. I will make a longer dew shield and try again.



Thanks!

Larry
Attachments
Leo_Triplet-RGB-session_1full crop-DeNoiseAI-low-light.jpg
For visual:
10" Skywatcher collapsible goto dob, various EP's and a Celestron StarSense auto align.

For imaging:
Orion 8" astrograph 800mm @ F3.9
Eq6-R Pro controlled by APT via EQmod with an OTA mounted mini PC
Tele Vue Paracorr Type 2 coma corrector
Altair Hypercam 26C
Image
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starfield United States of America
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Re: What causes this?

#5

Post by starfield »


I'd vote for a reflection in this case too.
Scopes: Esprit 100, 12.5" Telekit Dob
Camera: 294 MC Pro, 224 mc, 2600mm
Guiding: ZWO 290 mini on 120mm guide scope
Mounts: EQ6R-Pro, EQ Platform.
Filters: Optolong L-Pro & L-Enhance, Chroma 36mm LRGB, 5nm HA, 3nm OIII, 3nm SII.
Software: SharpCap, SGP, StarTools 1.7, Photoshop, Pixinsight
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Astro Photos:https://www.astrobin.com/users/starfield/
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Larry 1969 United States of America
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Re: What causes this?

#6

Post by Larry 1969 »


I made a temporary dew shield extender from some large, black paper. It wasn't perfectly round, and I had to remove it to take the flats, so I got some poor correction but, that glaring, ringing artifact was substantially reduced. I had rotated the camera 120 degrees from the original image, and you can still see some of it, but it's greatly reduced.

Any idea where I can get a 24" dew shield for my 8" reflector?

Larry
Attachments
InkedM78_2_-RGB-session_final1-DeNoiseAI-low-light_LI.jpg
For visual:
10" Skywatcher collapsible goto dob, various EP's and a Celestron StarSense auto align.

For imaging:
Orion 8" astrograph 800mm @ F3.9
Eq6-R Pro controlled by APT via EQmod with an OTA mounted mini PC
Tele Vue Paracorr Type 2 coma corrector
Altair Hypercam 26C
Image
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AstroBee United States of America
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Re: What causes this?

#7

Post by AstroBee »


You might want to look at an arts & crafts supply type store for a sheet of black abs plastic. You may need to get a different color and paint it flat black on the inside.
If you want the best material, you should get flockboard. The only place I know of that sells it is this source. https://www.fpi-protostar.com/flockboard.htm
He has a bad reputation of taking a very long time to fill orders because I think he waits till he has enough orders to buy a full roll before he fills the smaller orders. It took me almost 3 months to get my material but it is a very, very nice, stiff, extremely flat black material that makes a perfect dewshield.
https://youtu.be/S2zy6jdRIzE
Greg M.~ "Ad Astra per Aspera"
Scopes: Celestron EdgeHD14", Explore Scientific ED152CF & ED127 APO's, StellarVue SV70T, Classic Orange-Tube C-8, Lunt 80mm Ha double-stack solar scope.
Mounts: Astro-Physics Mach One, iOptron CEM70EC Mount, iOptron ZEQ25 Mount.
Cameras: ZWO ASI2600mm Pro, ZWO 2600MC Pro, ZWO ASI1600mm
Filters: 36mm Chroma LRGB & 3nm Ha, OIII, SII, L-Pro, L-eXtreme
Eyepieces: 27mm TeleVue Panoptic, 4mm TeleVue Radian, Explore Scientific 82° 30mm, 6.7mm , Baader 13mm Hyperion, Explore Scientific 70° 10mm, 15mm, 20mm, Meade 8.8mm UWA
Software: N.I.N.A., SharpCapPro, PixInsight, PhotoShop CC, Phd2, Stellarium
https://www.nevadadesertskies.com
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Larry 1969 United States of America
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Re: What causes this?

#8

Post by Larry 1969 »


AstroBee wrote: Sun Feb 27, 2022 8:58 pm You might want to look at an arts & crafts supply type store for a sheet of black abs plastic. You may need to get a different color and paint it flat black on the inside.
If you want the best material, you should get flockboard. The only place I know of that sells it is this source. https://www.fpi-protostar.com/flockboard.htm
He has a bad reputation of taking a very long time to fill orders because I think he waits till he has enough orders to buy a full roll before he fills the smaller orders. It took me almost 3 months to get my material but it is a very, very nice, stiff, extremely flat black material that makes a perfect dewshield.
https://youtu.be/S2zy6jdRIzE
Thanks!

Larry
For visual:
10" Skywatcher collapsible goto dob, various EP's and a Celestron StarSense auto align.

For imaging:
Orion 8" astrograph 800mm @ F3.9
Eq6-R Pro controlled by APT via EQmod with an OTA mounted mini PC
Tele Vue Paracorr Type 2 coma corrector
Altair Hypercam 26C
Image
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