Finally testing new CaK filter stack

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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Merlin66
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Finally testing new CaK filter stack

Post by Merlin66 » Fri Jun 22, 2018 1:43 am

I've recently upgraded the Omega (three filter) CaK stack to include a Baader CCD (Blue) filter as an ERF. I also added a SkyBender filter tilter - to bring the 2A filter closer to CWL.

Been frustrated by the weather - if not rain then thick cloud...
Well, this morning there was thin high cloud so let's give it a go. Mounted on the ED80/HEQ5, with the ASI 174MM - Success!!!!!

The video files (to be processed ASAP) clearly show the current sunspot groups and large areas of bright flocculi.

The 2" filter spacer tubes hold the Baader CCD-B well in front of the stack; inside the tube, in front of the gold SkyBender is a 390nm cut filter (acts as a secondary ERF) then about 30mm spacer to a 80nm bandwith 394nm CWL filter as a pre-filter then finally the 2A bandwidth, 393.7nm CWL mounted in the SkyBender.....

I'm impressed!!! It actually works!!!
So far so good.
Onwards and Upwards
100_3486.JPG
Arrangement of CaK filter stack
100_3486.JPG (271.53 KiB) Viewed 799 times
100_3485.JPG
CaK filter stack ASI174MM
100_3485.JPG (255.74 KiB) Viewed 799 times
100_3484.JPG
ED80 CaK stack ASI 174mm
100_3484.JPG (284.68 KiB) Viewed 799 times
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.yahoo.com/neo/groups/ast ... scopy/info
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer

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Re: Finally testing new CaK filter stack

Post by Valery » Fri Jun 22, 2018 3:27 am

Congratulates with a new setup version! But we'd like to see the images you took with it.


Valery
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

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Re: Finally testing new CaK filter stack

Post by TheSkyBurner » Fri Jun 22, 2018 3:38 am

that system looks awesome! processing cak images a bit different than ha images, so do not be discouraged on your first attempt at creating a sharp image. it took me almost a year before i realized i was over cooking my images with wavelets

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Re: Finally testing new CaK filter stack

Post by TheSkyBurner » Fri Jun 22, 2018 3:40 am

i just noticed, you have a 1.25" gold skybender, with the external t-mount adapter. My 2" is gold and does not have a t mount.

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Re: Finally testing new CaK filter stack

Post by Merlin66 » Fri Jun 22, 2018 4:16 am

SkyBurner, yeah.... I sent you an email about this SkyBender.....
Valery,
Just processing the images - coming soon...
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.yahoo.com/neo/groups/ast ... scopy/info
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer

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Re: Finally testing new CaK filter stack

Post by Merlin66 » Fri Jun 22, 2018 4:40 am

This image is probably representative of my ability to focus and tune the filter stack....
Processed in AS3!, no wavelets no curves.....
CaK_112110_220618.png
CaK filter stack, ED80+ASI 174
CaK_112110_220618.png (1.6 MiB) Viewed 787 times
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.yahoo.com/neo/groups/ast ... scopy/info
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer

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Re: Finally testing new CaK filter stack

Post by TheSkyBurner » Fri Jun 22, 2018 5:09 am

I just searched my email, there is no message from you. I dont think it went through?

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Re: Finally testing new CaK filter stack

Post by TheSkyBurner » Fri Jun 22, 2018 5:19 am

Okay i just found the email, it says its from admin@solarchatforum and was not in my inbox or spam folder, but the important messages folder that i never check :)

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Re: Finally testing new CaK filter stack

Post by Merlin66 » Fri Jun 22, 2018 6:09 am

A touch of colour and re-aligned axis.....
CaK_220618a.png
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CaK_112110_crop.png
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"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.yahoo.com/neo/groups/ast ... scopy/info
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer

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Re: Finally testing new CaK filter stack

Post by Merlin66 » Fri Jun 22, 2018 6:29 am

I bought an ASI 183MM earlier this year to compliment the shorter focal length ED80 and "improve resolution" for solar imaging.
Cutting a looooong story very short, ZWO finally admitted "technical problems when the ASI 183 is used for narrow band solar imaging" and accepted a return.
I'm now looking seriously at the ASI 1600MM as a replacement.
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.yahoo.com/neo/groups/ast ... scopy/info
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer

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Re: Finally testing new CaK filter stack

Post by Valery » Fri Jun 22, 2018 8:55 am

Thanks, Ken, for the images.

Seems to me that a single Lunt B600 CaK is much better than this army of filters and mechanics.

May be if good filters will become available, the skybender will get a good use.


Valery
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

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Re: Finally testing new CaK filter stack

Post by Merlin66 » Fri Jun 22, 2018 9:09 am

I probably agree, but at a total price of a few hundred dollars it's much cheaper than the commercial options.....
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.yahoo.com/neo/groups/ast ... scopy/info
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer

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Valery
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Re: Finally testing new CaK filter stack

Post by Valery » Fri Jun 22, 2018 12:38 pm

I'd better pay more for a real result, than pay several hundreds backs for doubtful result.
"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.

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Re: Finally testing new CaK filter stack

Post by TheSkyBurner » Fri Jun 22, 2018 7:00 pm

Valery: you personally buy and resell/return pst etalons to "find the best one"

So you are hand picking and sorting through rejects yourself. You just didnt buy one thing something and get satisfied with how you feel about your system.

Merlin is using omega optical filter, which has been known and reported to be very inconsistent. Coronado filters are also very inconsistent, the banding problem still exists on SolarmaxIII filters and those are not cheap at all.. Lunt filters pressure tuned filters on the ls60tha and ls50tha are, also very inconsistent.

He can certainly return it and get a second one to test, and third one and fourth one and fifth one to find the good one.

Lunt does something similar, they are not making 1 filter at a time, and they probably have rejects and errors every now and then.
Its called quality control


The hobby is a gamble unless you spend thousands of dollars you purchase the premium grade filters.


Merlin you did a good job, and the image looks fine. It could be your scope is not well suited for below 400nm. So even if you did buy the lunt filter, you might still get a similar result. The other solution is to try collimating the omega filter. They require a very specific beam path. This is how peterZ is using his omega filter system. He built a collimating device.

Valery it seems is always pointing out flaws with low budget items and never offering advice other than to get brand new equipment like an sct telescope with his d-erf filter.

Here is a picture and schematic of peters telecentric/collimator/corrector.
005.jpg
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Re: Finally testing new CaK filter stack

Post by TheSkyBurner » Fri Jun 22, 2018 7:05 pm

and an image with tags to show that he indeed is using an omega filter stacked on a lunt filter.

http://www.pbase.com/p_zetner/image/163467851

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Re: Finally testing new CaK filter stack

Post by marktownley » Sat Jun 23, 2018 6:54 am

Cool setup Ken and nice results!
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http://brierleyhillsolar.blogspot.co.uk/
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Re: Finally testing new CaK filter stack

Post by Merlin66 » Sat Jun 23, 2018 8:13 am

Thanks Mark, appreciate.
The conditions were far from ideal.
I hope to get better weather and a better camera soon.
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.yahoo.com/neo/groups/ast ... scopy/info
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer

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Re: Finally testing new CaK filter stack

Post by marktownley » Sat Jun 23, 2018 8:53 am

Something else to try Ken, imaging at that scale for full disk reduce the aperture - say 50mm, it will be much more friendly for the seeing and also put a slower light cone into the filters and tighter bandpass giving better contrast still.
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http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!

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Re: Finally testing new CaK filter stack

Post by Merlin66 » Sat Jun 23, 2018 9:00 am

Mark,
Thanks for the suggestion.
I’ll try it the next opportunity.
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.yahoo.com/neo/groups/ast ... scopy/info
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer

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