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Newton F3.4 bad stars and double spikes on only one side

ToupTek OAG Acquisition Deep Sky Troubleshooting Tilt
9 replies•553 views
Marc-Antonio Fischer avatar
Marc-Antonio Fischer avatar
Hello guys!
I hope someone can analyse my image and can tell me what is going on.

Setup:

SW 300 Quattro
Touptek 2600mm
ZWO filterwheel 2x
OAG Touptek (Screwed)
Coma corrector: https://www.teleskop-express.de/de/astrofotografie-und-fotografie-15/bildfeld-korrektoren-fuer-teleskope-138/ts-optics-newton-koma-korrektor-0-85x-reducer-vollformat-3-anschluss-5092 x0.85
3 inch focuser: https://www.teleskop-express.de/de/teleskop-zubehoer-5/auszuege-teleskopadapter-motorfokus-296/okularauszuege-mikrountersetzung-92/ts-optics-3-zoll-rap-newton-okularauszug-mit-tilting-moeglichkeit-und-basis-fuer-tuben-ab-300mm-durchmesser-15768 


My problem is, that my stars look like that, with all filters. 



The middle of the image looks quite perfect to me. (Could be seeing or bad tracking for the slight misshape)

Left is okay, but on the right side holy. These double spikes f me up. 
What is the cause of that? Tilt? collimation? 
Have any of you an idea how i can figure that out.

Currently I think its a heavy tilt on the right side, but why are the stars "fine" on the other then? 
Could that be the secondary or primary mirror which is decolimated?

thank you guys.

Marc
Reg Pratt avatar
Reg Pratt avatar
You definitely have tilt somewhere in your image train, likely in the sensor. Time to add a tilt adjuster if you're able.
Well Written Concise
andrea tasselli avatar
andrea tasselli avatar
Heavy tilt upper left - lower right. Shim it or get a TCU. I don't see anything else to worry about at this stage.
Oskari Nikkinen avatar
Oskari Nikkinen avatar
I agree with the comments about tilt, looks like you have a fair bit of it.

However, before adjusting tilt with a tilt adapter you should double and triple check that collimation of both mirrors is as close to perfect as it could possibly be. Collimation will add to tilt issues, and if you go ahead and adjust tilt with the scope out of collimation you can end up making things worse quite easily.
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Dale Penkala avatar
Dale Penkala avatar
Personally I think you have a couple of things going on but 1st I think your tilt is DEFINITELY an issue as all of us are in agreement above. 
I think once you get the tilt adjusted out you’ll find that your backspacing is off but you will need to get your tilt much better before you can confirm that.
From there I’d check your collimation but as @andrea tasselli said your not at that stage yet.
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Marc-Antonio Fischer avatar
Marc-Antonio Fischer avatar
Yeah, was thinking about tilt in the frist place too, beause the collimation is very good in my opinion (done with ocal pro) Thank you guys for the time! I will try hocus focus to find the tilt in nina. You got any other tips?
Marc-Antonio Fischer avatar
Marc-Antonio Fischer avatar
Oskari Nikkinen:
I agree with the comments about tilt, looks like you have a fair bit of it.

However, before adjusting tilt with a tilt adapter you should double and triple check that collimation of both mirrors is as close to perfect as it could possibly be. Collimation will add to tilt issues, and if you go ahead and adjust tilt with the scope out of collimation you can end up making things worse quite easily.

Thank you Oskari, was thinking the same, just wanted to hear another opinion from you guys Btw are you excited for your ONTC? ;)
Oskari Nikkinen avatar
Oskari Nikkinen avatar
Marc-Antonio Fischer:
Oskari Nikkinen:
I agree with the comments about tilt, looks like you have a fair bit of it.

However, before adjusting tilt with a tilt adapter you should double and triple check that collimation of both mirrors is as close to perfect as it could possibly be. Collimation will add to tilt issues, and if you go ahead and adjust tilt with the scope out of collimation you can end up making things worse quite easily.

Thank you Oskari, was thinking the same, just wanted to hear another opinion from you guys Btw are you excited for your ONTC? ;)

Oh, i thought your name looked familiar somehow . Very excited, it was high time for an upgrade and the ONTC makes the most sense out of all the options.
AstroShed avatar
AstroShed avatar
Marc-Antonio Fischer:
Yeah, was thinking about tilt in the frist place too, beause the collimation is very good in my opinion (done with ocal pro) Thank you guys for the time! I will try hocus focus to find the tilt in nina. You got any other tips?

This may help if you need to adjust for in camera sensor tilt, which many people do have…

https://youtu.be/Gw2oTwb4GjY?si=lRtbgiadyso2OsrC
Robert Habolin avatar
Robert Habolin avatar
Before you go checking for tilt, make sure collimation is spot on. And before you collimate, make sure your secondary is centered in the focuser. You can easily check that with the concenter tool that TS sells. I had a problem recently there my secondary was slightly too far out in the tube. I could collimate to perfection and yet stars were warped at the edge of the field. And simply  cos the secondary wasn’t perfectly level and centered to the focuser. So check that, then do a very careful collimation, at F3 you need to be very precise or you’ll get distortions, which could easily been misinterpreted as tilt.
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