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Getting rid of my Newtons Rings issue


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Hi folks I do not post much here but I am so excited!!

I have a single stack Lunt 80mm Ha scope, ASI174MM aand ASI120MC-S cams, Powermate 2.5x and have been fighting Newtons Rings from day one. I had posted this issue on other forums before and it was suggested that I try a Teleskop Service T2 Tilt Adjuster but I found it frustrating the camera body blocked access to the adjustment screws and I had to take it off to adjust and reassemble it take another image and repeat. I never got it to work as I could not figure out which of the 3 screws to turn nor remember which one I had turned or which direction. (I have PTSD my short term memory is awful)

 

 

 

 

sunNR1

Recently after posting some images to Facebooks Solaractivity page https://www.facebook.com/groups/solaractivity/ 

 

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A few days ago I was talking to someone on Solaractivity Facebook page who was giving me suggetions to try and fix my problems most of which I had tried already. It turned out I was talking to Jen Winterthe Owner of Daystar Filters and she made one final suggestion. Jen suggested that I try one of the Moonglow Technologies Interference Eliminators to see if it would help my problem.

It arrived a few days ago and even though the seeing was 1/5 and rotten I just had to try it out. Please keep in mind I did a fast setup and seeing was so poor focus is not perfect and did not clean my optics first. What I wish for you to focus on are the Newton's Rings. Once the Interference Eliminator is attached it does not need to be removed to make adjustments just loosen 2 medium sized thumb screws make adjustment and tighten back down take your image again and adjust as needed.

IT WORKED! There are still some fine lines in the images but the sun went down before I could tweak the Interference Eliminator. Actually the same fine lines are in both images perhaps they are not from Newton rings after all)

 

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I will post more tests to this thread as soon as health, weather and time permit.

please let me know what you think. If you use this device share your results here and let us know what you like or do not like anout it I am eager to learn more and thanks to the results even more excited about learning Solar Imaging.

Edited by AstroEd
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That's a great result. My setup suffers from the same problem and have only ever managed to get around it by allowing the FOV to move while recording - which sort of averages it out. Nice work! Looks like this might be a birthday present for me! :-)

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I tried to shift the image during recording and at best it mad the newtons rings lighter but did not eliminate them, I also still need to learn proper or easy way to do flats and incorporate them into my stack.

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5 hours ago, bunnygod1 said:

Good end result. What are the files though, i don't think i have seen them before?

I am not sure what you mention but the B/W images are made from avi files that I stack in autostakkert!2 keeping the best 25-50% of anywhere from 1000-3000 frames and save as TIF files, then run in Registax for wavelets which to be honest I do not yet understand the settings I just play with sliders till they look better than the origional. Then I save them as JPG and open in Photoshop CS5 to adjust histogram and curves convert to 8bit and grayscale, then I use the Duotone to add color to taste. Still learning what looks right.

When I post I tend to post the best single frame which looks soft out of focus then the stacked with wavelets image, then the final color so people can see the progress of the image as in the images with the 3 views.

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Also forgive me I do not know best way to post images in forums so linked directly to my Flickr page which has my Astronomy, Metal Detecting, and Dog pictures so I am sorry if you ended p seeing images not related to this post I am still learning, I have not figured out yet how to lock out sections of my Flickr albums.

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43 minutes ago, AstroEd said:

I am not sure what you mention but the B/W images are made from avi files that I stack in autostakkert!2 keeping the best 25-50% of anywhere from 1000-3000 frames and save as TIF files, then run in Registax for wavelets which to be honest I do not yet understand the settings I just play with sliders till they look better than the origional. Then I save them as JPG and open in Photoshop CS5 to adjust histogram and curves convert to 8bit and grayscale, then I use the Duotone to add color to taste. Still learning what looks right.

When I post I tend to post the best single frame which looks soft out of focus then the stacked with wavelets image, then the final color so people can see the progress of the image as in the images with the 3 views.

Sorry I meant the fine lines not files, no idea why I wrote that :happy8:

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I am trying to figure that out myself if you notice they are in both images the before with the Newton Rings and the after using the Interference Eliminator. I am hoping it is some kind of noise the seeing was terrible and I also do not think I had the scopes preassure tuner set right as I never saw any filaments or proms the entire time I was testing.

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Hi Ed, you can take flats and incorporate them in AS2 or take them in Firecapture while capturing, haven't tried the FC method yet.
I use a piece of cling film over the front of the scope to blur the image, found this works best for my setup.
They don't always work though no idea why :)

Dave

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The banding on your Ha is really pronounced, far worse than my set up.  I have a Lunt 60DS and the same cameras as you.  I also have a Quark and here is what I find.

My ASI120 produces bands but they are fairly closely spaced with my Lunt and of course get worse with a Barlow.  I tried a tilt adaptor and after endless fiddling I got rid of the bands, but the camera, especially with a Barlow, was so far out of alignment it wasn't in correct focus and I saw a slight vignetting, so for me it was a non-starter.

My ASI174 produces virtually no banding in my Lunt, it does seem to have a slight smear pattern, rather like a cloud under Ha, but flats applied during capture with Firecapture sort that out. I took it apart and cleaned the chip and optical window and the cloud patern has almost gone.

I get similar results with my Quark, but tend to use a focal reducer on my Quark and this reduces the banding and cloud pattern.

To sort out my banding I do two things, firstly use flats in Firecapture by applying enough out focus to smooth out the features and use the flat feature and then let the sun drift a little in the frame during capture. A drifting sun is fairly easy for me, I generally don't align my mount, just point it in the rough direction of north.  Once the video is stacked nearly all of my banding disappears.

The Moonglow filter looks very interesting, I am glad it has fixed your banding problem.

What does look slightly worrying is you appear to get severe banding in your white light shots, I have got that right? I have never had banding in white light and looks really odd. Do you fit an IR filter between your camera and filter?  I don't bother with a filter on Ha, it is already IR blocked and fit an IR filter before my wedge in white light. If you are fitting an IR filter between camera and Ha blocking filter or between camera and wedge, it might well be the IR filter which is causing the banding?

Also do you notice any difference between an ASI120 and an ASI174?  I think you should find the banding on an ASI174 much less, you might want to check on the ASI website to see what it says.

I hope that helps

Robin

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The banding has been that way from day one when I use the Barlow 2x or Powermate 2.5x even with out the Barlow at full disk I can see slight banding straight across the whole surface but it is real faint in the finished image. I can not wait for clear skies with good seeing to do more tests with the Interference Eliminator.

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  • 1 year later...

I was about to ask about fixing banding but I think the solution has just presented itself. I have tried using a tilt adapter both before and after the filter. Placed before had no impact and surprisingly, neither did after. However after reading this you have prompted me to check whether they rotate with the two camera I am using. Then I can either address the window or reassess the tilt adapter.

Cheers

Mike

 

 

 

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Skybadger,

I am very new at this and have a lot to learn but so far the Interference Eliminator has been my best option, I tried another tilt ring device that I never figured out and to get to the Allen screws I had to remove the camera every adjustment and for me that was too much because by time I got it back together I would for get what score I adjusted what direction. I have not imaged much last year due to hip issues and a Total hip replacement, and I never set up in winter. I look forward to setting up in the months to come.

I do have about 100 GB of data I have not processed yet. I will post them later.

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  • 3 years later...

I have been away from imaging for almost 4 years, I quit due to a hip replacement and just never got back into it, but I hope to return soon. After reading these old posts again I am very upset by all of my typos and I will try to do better in the future.

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This thread is years old.... but it shows the problem of NR continues.

Sometimes tilting helps, sometimes plastic bags work, adding an optical wedge sometimes help, the problem continues.

The NR are caused by etalon type interference in the cover plate of the sensor chip.

As this cover plate cannot be removed or changed the only option we have is to tilt the cover plate to change the spacing of the fringes.

some cameras are worse than others. The ASI 174mm and ASI 1600mm I use both suffer from NR when used with effective focal ratio >f10.

such is life.

 

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4 hours ago, AstroEd said:

I have been away from imaging for almost 4 years, I quit due to a hip replacement and just never got back into it, but I hope to return soon. After reading these old posts again I am very upset by all of my typos and I will try to do better in the future.

Welcome back Ed, keep in touch and let us know how you get on with solar imaging.

Dave

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I agree on the TS tilter. Poor design IMO. I replaced the thumbscrews when one broke.
Then reversed the tilter to bring the thumbscrews away from the camera.

Ironically, I spent years trying to get stronger NR when testing large optical flats.
I went with an orange, mercury lamp in the end.
It saved going across the road to the street lamp carrying two large blanks. :blink:

The '174 is fine now if I avoid noise from too much gain.
I went through a period when everything was impossibly grainy.
That went away too. Software/firmware update? Probably. Was I there? :rolleyes2:

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