Newton Rings

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photon hunter
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Newton Rings

Post by photon hunter » Sat Mar 26, 2016 10:14 pm

I have been having trouble with newton's rings when ever I use a Barlow on the following assembly: Lunt 100, double stacked with Solar max 90, with either a DMK-41 or zwo 177 cameras. Any suggestion as to how to correct/eliminate the rings?
Thanks
Burton

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marktownley
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Re: Newton Rings

Post by marktownley » Sun Mar 27, 2016 8:24 am

Tilt the camera or take a flat :)
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_Zakalwe
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Re: Newton Rings

Post by _Zakalwe » Sun Mar 27, 2016 11:52 am

As Mark says, tilting the camera works well. I use a Rowan Astronomy tilt-adapter with my ASI174 camera and it works very well.

photon hunter
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Re: Newton Rings

Post by photon hunter » Sun Mar 27, 2016 11:22 pm

Thanks Mark and Zakalwe. Will try flats first, if no success then the adaptor. When using the adaptor does the tilt throw one side out of focus?

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MapleRidge
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Re: Newton Rings

Post by MapleRidge » Mon Mar 28, 2016 12:06 am

Hi Burton...

The amount of tilt is very slight, so focus should not be affected.

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grimble_cornet
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Re: Newton Rings

Post by grimble_cornet » Mon Mar 28, 2016 1:34 pm

I used to use a DMK41 on my LS100 (and several other scopes) and found that a 'clingfilm flat' solved the problem (search the forum for instructions) unless I was using a TV x2.5 Powermate which seems to be very prone to NR. The tilt method will also work (I made my own unit and have also used a commercial one) BUT....... with early ZWO camera the tilt required was so extreme that I had to fit longer screws to the unit and yes, the focus was effected!
Tiltometer+with+TV+Powermate.jpg
Tiltometer+with+TV+Powermate.jpg (156.6 KiB) Viewed 1682 times
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marktownley
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Re: Newton Rings

Post by marktownley » Mon Mar 28, 2016 2:34 pm

Cool design Mike!
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Derek Klepp
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Re: Newton Rings

Post by Derek Klepp » Mon Mar 28, 2016 8:21 pm

Good luck .I find at high mag I see some rings but the flat method usually works well.But I take a defocused flat straight away

EmilN
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Re: Newton Rings

Post by EmilN » Thu Mar 31, 2016 8:41 am

Hi guys. I am new here so please help me with the terminology. I recently purchased PG Chameleon with IMX264 and I see a lot of NR. I am familiar with the tilt method but what is "flat"?

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robert
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Re: Newton Rings

Post by robert » Fri Apr 01, 2016 8:41 am

Try searching the forum, there are several threads on flats, bag flats etc. Mark Townley and Alexandra Hart (Montana) have plenty to say about flats.
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