blocking filter chit chat chop chop - lets cut it out.

Frankenscope? Let's see it!***be advised that NOTHING in this forum has been safety tested and you are reading and using these posts at your own peril. blah, blah, blah... dont mess around with your eyesight when it comes to solar astronomy. Use appropriate filtration at all times...
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MalVeauX
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Re: blocking filter chit chat chop chop - lets cut it out.

Post by MalVeauX »

That's brilliant Apollo, a 1 inch thick tilting chamber that can take 1.25" filters is golden for this.

Very best,


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MalVeauX
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Re: blocking filter chit chat chop chop - lets cut it out.

Post by MalVeauX »

Heya,

Update.

I have the 2nd 1.7A filter. I stacked them both in the Skybender, one in the tilt chamber with just enough tilt to remove a reflection and keep highest contrast on features and diminish surface brightness. The 2nd 1.7A filter is secured to the camera nose with no tilt needed. This train follows a single PST etalon.

So the train is:

IMX290 sensor -> 1.7A BF -> Skybender with 1.7A BF tilted -> PST etalon -> 50mm D-ERF -> Focuser -> Telescope (120mm F10)

AR2808_HA_120mmF10_290MM_81frames_PSTEtalon_17ABFX2_UnprocVSProc_BW_03142021.jpg
AR2808_HA_120mmF10_290MM_81frames_PSTEtalon_17ABFX2_UnprocVSProc_BW_03142021.jpg (155.83 KiB) Viewed 2504 times
PromsLimb_HA_120mmF10_290MM_81frames_PSTEtalon_17ABFX2_UnprocVSProc_BW_03142021.jpg
PromsLimb_HA_120mmF10_290MM_81frames_PSTEtalon_17ABFX2_UnprocVSProc_BW_03142021.jpg (196.62 KiB) Viewed 2504 times
PromsLimb_02_HA_120mmF10_290MM_81frames_PSTEtalon_17ABFX2_UnprocVSProc_BW_03142021.jpg
PromsLimb_02_HA_120mmF10_290MM_81frames_PSTEtalon_17ABFX2_UnprocVSProc_BW_03142021.jpg (162.39 KiB) Viewed 2504 times
Conclusion & Thoughts:

I think there is an increase in contrast for sure, just judging from the unprocessed images, I was able to see dark filaments and a bright plage area. The double limb is virtually gone, except towards the edges where the bandpass rolls off but in this case its a nice thing to see because it shows how the two 1.7A filters stacked nearly eliminate the double limb compared to the edges where the effect isn't there, so you can see an obvious double limb. This is not optimized yet, so I still have a lot more fiddling to do for placement, tilt, tuning, etc. But so far, this is very promising. This is as close to a double stack as I've been able to get without two etalons and it's way less fussy than dealing with two etalons. It's not perfect, there's still a hint of double limb (and it comes out more depending on the processing you do). But it's very close. I suspect with a better etalon this would be even better (again this is just a PST etalon with a small sweet spot and only about 0.9A maybe?). A good 0.7A filter would probably have no double limb I wonder?

Transmission is good still, through the above imaging train, I imaged at 5ms exposure time for my histogram and no gain.

Seeing wasn't great today, but it was enough to allow the 120mm aperture to get close enough to good resolution to inspect features to see how the contrast is in better detail. I will test again on a better seeing day with a more optimal tuning setup when I have better time.

Very best,


AndiesHandyHandies
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Re: blocking filter chit chat chop chop - lets cut it out.

Post by AndiesHandyHandies »

Hi

Will this idea work for visual use?

Cheers. Andrew.


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MalVeauX
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Re: blocking filter chit chat chop chop - lets cut it out.

Post by MalVeauX »

AndiesHandyHandies wrote: Mon Mar 15, 2021 9:42 am Hi

Will this idea work for visual use?

Cheers. Andrew.
Hi, yes, it's the same either way (visual or imaging). I used it visually to test as well and the view was dimmer as expected, just as a double stack etalon would be dimmer, but with high contrast and was still very pleasing to view through (8mm was plenty to pass the disc), but without needing a 2nd etalon.

Very best,


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Re: blocking filter chit chat chop chop - lets cut it out.

Post by MAURITS »

Bravo for the inventive idea and all the tests about a second blocking filter.
I don't understand this difficult system, but I hope one day something like that can go in production ... 👍😀
Last edited by MAURITS on Mon Mar 15, 2021 4:10 pm, edited 1 time in total.


Regards,
Maurits

Vista del Cielo Observatory

www.vistadelcielo.be
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eroel
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Re: blocking filter chit chat chop chop - lets cut it out.

Post by eroel »

Hi:
Thanks for a really interesting thread with a lot of experiences.
Best regards and keep well.
Eric.


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Re: blocking filter chit chat chop chop - lets cut it out.

Post by AndiesHandyHandies »

MalVeauX wrote: Mon Mar 15, 2021 12:00 pm
AndiesHandyHandies wrote: Mon Mar 15, 2021 9:42 am Hi

Will this idea work for visual use?

Cheers. Andrew.
Hi, yes, it's the same either way (visual or imaging). I used it visually to test as well and the view was dimmer as expected, just as a double stack etalon would be dimmer, but with high contrast and was still very pleasing to view through (8mm was plenty to pass the disc), but without needing a 2nd etalon.

Very best,
Hi

I am using a 1.5A Omega filter from a seconds pair, Its a pretty good one, in my PST mod as the blocker and I nearly see the surface details as on Gong images with a x-polariser to dim down. My PST looks like 0.75A from Daystars site images. I am going to try the obviously seconds one instead. I have it up front in the collimated beam so I am hoping it will not show the cosmetic features as its in phase space.

Cheers. Andrew.


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Re: blocking filter chit chat chop chop - lets cut it out.

Post by mdwmark »

Hi Marty,
Your images are well processed but you are in the red wing. If you see high contrast at the tips( like the prominences images) , that is a good sign you need to move blue about .5ang. When you are in the center of the Ha line, the disk will look softer.
Mark W.


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