11" SCT for imaging at 393nm.

this is the main message area for anything solar :)
Post Reply
User avatar
Valery
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 4059
Joined: Sun Nov 18, 2012 3:13 pm
Has thanked: 156 times
Been thanked: 893 times

11" SCT for imaging at 393nm.

Post by Valery »

Leif, Alfred, Alexandra and Mark,

With a 230mm aperture stop a C11 SCT becomes fully diffraction limited at 393nm wave length.

With a 250mm aperture stop a C11 is not diffraction limited, but a correct postprocessing will completely remove the SA impact on the image.

Here is the image I've took with my nully corrected (in green light) C11 at full aperture(!), ARIES DERF, PST CaK Mod, Basler 1920-155 camera. My proprietary image processing. Diffraction limit has been reached.
All these graphs about Strehl of SCT are good, but the reality is a bit different and this gives us a hope that some other solar imagers will be able to take same or better images than I was able to take.

To see the image in a full resolution - right click on it and open it in a separate window.

Valery

_2018 08 08 UT06h 07m DERF ARIES C11 PST CaK Basler 1920.png
_2018 08 08 UT06h 07m DERF ARIES C11 PST CaK Basler 1920.png (1.35 MiB) Viewed 4644 times
Last edited by Valery on Fri Oct 18, 2019 3:31 am, edited 1 time in total.


"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.
User avatar
MalVeauX
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 1858
Joined: Tue May 09, 2017 7:58 pm
Location: Florida
Has thanked: 1171 times
Been thanked: 1360 times

Re: 11" SCT for imaging at 393nm.

Post by MalVeauX »

Valery wrote: Wed Oct 16, 2019 2:47 pm My proprietary image processing. Diffraction limit has been reached.
All these graphs about Strehl of SCT are good, but the reality is a bit different and this gives us a hope that some other solar imagers will be able to take same or better images than I was able to take.
Hello Valery,

I would certainly like to learn more. My C8 Edge + Aires D-ERF is ready and willing to do CaK, it was one of the driving factors getting the tri-band D-ERF rather than just an HA D-ERF from Baader. Could you suggest how best to achieve focus in 393nm? Or make an aperture mask to what focal-ratio? Or can you share more about how to process 393nm to remove the SA and other problems? I'm curious of your proprietary processing?

Thanks!

Very best,


User avatar
marktownley
Librarian
Librarian
Posts: 42272
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 20435 times
Been thanked: 10243 times
Contact:

Re: 11" SCT for imaging at 393nm.

Post by marktownley »

Valery.

A fantastic image as always. You are the only person, globally, who is getting quality images like this at 393nm - at this scale and using these apertures. No one else is coming close to the quality. So, being a scientist I like to look at all the variables that culminate in the final image and see how I can use the techniques in my own results.

The equipment you use is off the shelf - was there a barlow used in the above image, or, is it taken at f10? If f10 then you're undersampling with those 5.86um pixels? If a barlow, which one?

Like Marty I would very much like to hear, in detail, your proprietary image processing, as if it can remove SA from images with your setup, then applying the same process to images taken by others at different apertures and potentially scopes.

We all suffer from SA to a greater or lesser degree with our CaK images and setups, so, would be very interested to how post processing can remove it, as, there are many forum members here who would appreciate and benefit from your knowledge.

Thanks

Mark


Image
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!
User avatar
yltansg
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 2798
Joined: Sat Jun 14, 2014 9:33 am
Location: Singapore (1.3N, 103.7E)
Has thanked: 1446 times
Been thanked: 1423 times

Re: 11" SCT for imaging at 393nm.

Post by yltansg »

Thanks Valery. Your posting tells me that there are many things I need to learn and improve my imaging and post-processing using full aperture imaging with my ARIES D-ERF.

Alfred


Starry Jack
Almost There...
Almost There...
Posts: 783
Joined: Tue Feb 03, 2015 3:44 pm
Location: Vista, CA
Has thanked: 141 times
Been thanked: 240 times
Contact:

Re: 11" SCT for imaging at 393nm.

Post by Starry Jack »

Ummm , I still think Val is cheating by using a space suit and a go pro unit a few miles above the surface. It’s the only plausible explanation for any of his high res work.

Seriously good stuff.


Explore Scientific 152mm f6.5 achromat
Aeries D-ERF
Quark Chromosphere f27 native, (f14 when focal reduced)
Mallincam .5x focal reducer (large format)
12nm Filter
ZWO174 (IMX249 chip 5um)
Huge Sense of Adventure Viewing Creation
User avatar
Montana
Librarian
Librarian
Posts: 34560
Joined: Mon Oct 17, 2011 5:25 pm
Location: Cheshire, UK
Has thanked: 17667 times
Been thanked: 8789 times

Re: 11" SCT for imaging at 393nm.

Post by Montana »

"but a correct postprocessing will completely remove the SA impact on the image"

I would dearly love to know how you do this :)

Alexandra


User avatar
MAURITS
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 8507
Joined: Tue Nov 27, 2018 4:37 pm
Location: Belgium
Has thanked: 2412 times
Been thanked: 4786 times
Contact:

Re: 11" SCT for imaging at 393nm.

Post by MAURITS »

Fantastic detailed images Valery.


Regards,
Maurits

Vista del Cielo Observatory

www.vistadelcielo.be
User avatar
marktownley
Librarian
Librarian
Posts: 42272
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 20435 times
Been thanked: 10243 times
Contact:

Re: 11" SCT for imaging at 393nm.

Post by marktownley »

What does the raw image look like for this one Valery, and how did you process it?


Image
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!
User avatar
eroel
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 9408
Joined: Mon Dec 19, 2011 10:45 pm
Location: México D.F.
Been thanked: 4904 times

Re: 11" SCT for imaging at 393nm.

Post by eroel »

Valery:
A super shot, I sure would love to know about you processing workflow.
Best regards,
Eric.


george9
Im an EXPERT!
Im an EXPERT!
Posts: 355
Joined: Tue Jan 26, 2016 1:28 am
Has thanked: 175 times
Been thanked: 426 times

Re: 11" SCT for imaging at 393nm.

Post by george9 »

Awesome results!

George


User avatar
Valery
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 4059
Joined: Sun Nov 18, 2012 3:13 pm
Has thanked: 156 times
Been thanked: 893 times

Re: 11" SCT for imaging at 393nm.

Post by Valery »

langleif2 wrote: Thu Oct 17, 2019 5:30 pm It seems almost unbelievable at that image scale without some kind of corrector. But a German optical solar expert once said to me he didn't believe the plot about spherochromatism for a SCT because the aberration should only be a 1/4 wave from 550 nm. Then it would perhaps match the image given. Or the classic C11 is just different from the rest of the pack!

Valery: "This gives us a hope that some other solar imagers will be able to take same or better images than I was able to take".

I don't think so. But you likely did this video in the morning and perhaps the key factor of this successful imaging is very short exposure time which is possible due to a very high transmission of the used DERF filter at this spectral area and due to a very high transmission of the narrow band 393nm CaK filter. Just a guess.

But you don't say much. You just pouring out sensationel images of the sleeve without telling how in detail. So it's hard to believe that you are not somehow "cheating" as a vendor of telescopes and accessories (no offence).

I know for sure, I won't be able to do that scale quality with my C8 not even close. My seeing don't allow that and I'm almost at the same latitude.
Leif,

I have repeatedly wrote here and at the Cloudy Nights solar forum that success is achieved not by those who for a long time and with a sad faces reasoaning that this or that is impossible or too difficult to achieve, but by those who have cast aside doubts, being self inspired by examples of the facts that all this is possible, go forward, despite all the difficulties and temporary setbacks.

Lets take your own example. Have you bought an UV-corrective barlow lens which you talked about sometime ago? If you bought it, have you ever tried it for imaging the sun in the UV and CaK? If yes, have you made an aperture stop for your C8 (to decrease it's spherical aberration)? If you have made it, have you ever use it for imaging in CaK? Have you ever tried to image the Sun in CaK with these two accessories together? If yes, how many times?

I am almost sure that you didn't do any of that. Instead of doing these very first(!) necessary(!) steps, you took a liberty to publically guess about my motives when I image the sun with a high resolution and publish the results!

If I'd only listen to those (DayStar and all), who constantly tell us that for solar observing/imaging there is no practical sense to consider, to buy, to use an aperture(s) larger than 4", I'd never get the results I finally get.
If I'd only listen to those, who tell us that SCT are completely useless for sun imaging in UV and CaK, I'd never get the results I finally get. And I knew about this SCTs major disadvantage - spherochromatism. I knew this 35+ years ago! And if only this knowelege has stopped me, I'd never get the results in CaK imaging with larger SCTs I finally get!

Note, please, - my own first results of trying to image the sun in Ha (not in the CaK!) with my C11 telescope were really disappointing! Absolutely awful results! But did this stop me? You all know well - it did't The reason of such first results was simple: I was too impatient and tried to image the sun with a full size 11" DERF next hour I finally get the cell for the DERF. It were done in July hot day between 14 and 15 of a local time at nearly 38C! And I silently told to myself - OK, no problem, lets try it early morning.


Valery.
Last edited by Valery on Sat Oct 19, 2019 7:26 am, edited 2 times in total.


"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.
User avatar
yltansg
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 2798
Joined: Sat Jun 14, 2014 9:33 am
Location: Singapore (1.3N, 103.7E)
Has thanked: 1446 times
Been thanked: 1423 times

Re: 11" SCT for imaging at 393nm.

Post by yltansg »

Hi Valery,

I am inspired by your never-give-up attitude. I have plenty of experimentations waiting for me.

Alfred


User avatar
marktownley
Librarian
Librarian
Posts: 42272
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 20435 times
Been thanked: 10243 times
Contact:

Re: 11" SCT for imaging at 393nm.

Post by marktownley »

Valery, did you use a barlow for this shot or is it at f10?


Image
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!
User avatar
Valery
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 4059
Joined: Sun Nov 18, 2012 3:13 pm
Has thanked: 156 times
Been thanked: 893 times

Re: 11" SCT for imaging at 393nm.

Post by Valery »

marktownley wrote: Sat Oct 19, 2019 7:43 am Valery, did you use a barlow for this shot or is it at f10?
Mark,

Of course, such a scale is impossible without a barlow lens, especially with IMX174 chip.


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.
User avatar
marktownley
Librarian
Librarian
Posts: 42272
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 20435 times
Been thanked: 10243 times
Contact:

Re: 11" SCT for imaging at 393nm.

Post by marktownley »

Valery wrote: Sat Oct 19, 2019 11:50 am
marktownley wrote: Sat Oct 19, 2019 7:43 am Valery, did you use a barlow for this shot or is it at f10?
Mark,

Of course, such a scale is impossible without a barlow lens, especially with IMX174 chip.


Valery
I thought so. What barlow did you use Valery?


Image
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!
User avatar
marktownley
Librarian
Librarian
Posts: 42272
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 20435 times
Been thanked: 10243 times
Contact:

Re: 11" SCT for imaging at 393nm.

Post by marktownley »

What barlow is it Valery?


Image
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!
User avatar
marktownley
Librarian
Librarian
Posts: 42272
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 20435 times
Been thanked: 10243 times
Contact:

Re: 11" SCT for imaging at 393nm.

Post by marktownley »

What 2x barlow are you using for this image Valery?


Image
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!
Post Reply