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Help me to know what is that...

Posted: Fri Jun 14, 2019 10:15 pm
by Ronnie_Clayton
Hello friends!

Last weekend I was doing some pictures and I've noticed an interesting effect (or issue). Using high gain appeared concentric rings (not newton rings I think) in center of picture...

Have you ever seen it before? What is that?

Equipment utilized:
Telescope: APM LZOS 152/1200 (triplet)
Solar Filter: SolarSPectrum 0,3A Research Grade
Telecentric Lens: Baader TZ3 and TZ4 (I´ve the same effect in both) and Baader 0,4x telecompressor.
Camera: Basler acA1920-155


BR

Ronnie

Re: Help me to know what is that...

Posted: Sat Jun 15, 2019 5:34 pm
by Bob Yoesle
Those appear to be either Newton's rings or FP etalon interference fringes:

https://en.wikipedia.org/wiki/Newton%27s_rings

https://en.wikipedia.org/wiki/Fabry%E2% ... rferometer

They could be an internal reflection issue with your imaging system, or there might be something amiss with your filter system; perhaps a decontacted polarizer or other filter component. I would send this image to the vendor for evaluation and forwarding to Solar Spectrum for analysis.

Re: Help me to know what is that...

Posted: Sat Jun 15, 2019 7:44 pm
by marktownley
I think it's just an internal reflection... Try without the telecompressor and see if the effect is still there, process of elimination...

Re: Help me to know what is that...

Posted: Sat Jun 15, 2019 9:41 pm
by Ronnie_Clayton
Thaks for your suppport Bob and Mark :-).

I´ve sent an e-mail directly to Mark from SolarSpectrum, he says me that he had never seen it before. Not Newton Rings like that, "looks like a topographical map". Mark asked me to try differents configs to try eliminate it like a Newton Rings (tilting the camera).
It is clouding this weekend here in Maringa, next weekend I will try other configs to verify it. But, it just appears in very high gain...

Ronnie