Rotation on meridian flip

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KathyNS Canada
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Rotation on meridian flip

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Post by KathyNS »


On a recent image image, I noticed considerable (5+ degrees) rotation between images taken before and after the meridian flip. Ordinarily, I would just crop off the edges and not worry about it. But there was a bright star in the field, and the diffraction spikes from the before and after frames didn't line up.

I know that the rotation indicates that something is not perpendicular to something else, but I am having trouble visualizing what. Before I give myself a headache, I thought I'd ask if anyone else has tracked down and fixed a similar problem.

For reference, it is an iOptron CEM-60. I recently re-balanced everything, and am happy with tracking, guiding, etc. The scope is a 200mm Newtonian, mounted with the focuser and camera down, in the zero position.
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DSO AP: Orion 200mm f/4 Newtonian Astrograph; ATIK 383L+; EFW2 filter wheel; Astrodon Ha,Oiii,LRGB filters; KWIQ/QHY5 guide scope; Planetary AP: Celestron C-11; ZWO ASI120MC; Portable: Celestron C-8 on HEQ5 pro; C-90 on wedge; 20x80 binos; Etc: Canon 350D; Various EPs, etc. Obs: 8' Exploradome; iOptron CEM60 (pier); Helena Observatory (H2O) Astrobin
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smeyer8015
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Re: Rotation on meridian flip

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Post by smeyer8015 »


Celestron Classic 8, Old Sears 60mm f/15 refractor, Old Edmund Scientific 6 inch F/8 newt, GSO 2" Diag, ES 30mm/70, ES 25mm/70, Orion 32 Super Plossl, Mead 24mm MA,
X-Cel LX 18mm, Luminos 15mm, F/6.3 reducer, Luminos 2.5x barlow, Telrad, Celestron 9x50 RACI, DIY Baader Solar Filter, Celestron Skymaster 20x80, Bresser EXOS-2 Goto, Revolution Imager R1

No trees were killed in the sending of this post. However, a large number of electrons were terribly inconvenienced
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KathyNS Canada
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Re: Rotation on meridian flip

#3

Post by KathyNS »


Interesting discussion. A lot of guesswork, and not much verification. But it gives me some ideas to work on.
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DSO AP: Orion 200mm f/4 Newtonian Astrograph; ATIK 383L+; EFW2 filter wheel; Astrodon Ha,Oiii,LRGB filters; KWIQ/QHY5 guide scope; Planetary AP: Celestron C-11; ZWO ASI120MC; Portable: Celestron C-8 on HEQ5 pro; C-90 on wedge; 20x80 binos; Etc: Canon 350D; Various EPs, etc. Obs: 8' Exploradome; iOptron CEM60 (pier); Helena Observatory (H2O) Astrobin
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Re: Rotation on meridian flip

#4

Post by turboscrew »


Please tell us, if you figure it out. I'm interested even if it doesn't concern me - at least for a while.
- Juha

Senior Embedded SW Designer
Telescope: OrionOptics XV12, Mount: CEM120, Tri-pier 360 and alternative dobson mount.
Grab 'n go: Omegon AC 102/660 on AZ-3 mount
Eyepieces: 26 mm Omegon SWAN 70°, 15 mm TV Plössl, 12.5 mm Baader Morpheus, 10 mm TV Delos, 6 mm Baader Classic Ortho, 5 mm TV DeLite, 4 mm and 3 mm TV Radians
Cameras: ZWO ASI 294MM Pro, Omegon veLOX 178C
OAG: TS-Optics TSOAG09, ZWO EFW 7 x 36 mm, ZWO filter sets: LRGB and Ha/OIII/SII
Explore Scientific HR 2" coma corrector, Meade x3 1.25" Barlow, TV PowerMate 4x 2"
Some filters (#80A, ND-96, ND-09, Astronomik UHC)
Laptop: Acer Enduro Urban N3 semi-rugged, Windows 11
LAT 61° 28' 10.9" N, Bortle 5

I don't suffer from insanity. I'm enjoying every minute of it.

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