March 12, 2023 102mm double and triple stack comparison with bonus full disk

this is the main message area for anything solar :)
Post Reply
Oak
Ohhhhhh My!
Ohhhhhh My!
Posts: 142
Joined: Mon Feb 07, 2022 6:16 pm
Has thanked: 288 times
Been thanked: 232 times

March 12, 2023 102mm double and triple stack comparison with bonus full disk

Post by Oak »

Hi All,

It's been months since I had any time to image, but I finally got a chance yesterday. I tested for the first time a triple stack configuration of quark+two Lunt40 etalons vs. quark with only a single 40mm etalon in the telecentric output.

A prior attempt showed that there were serious reflections between the two Lunt etalons. This time, I added a circular polarizer between the Lunt etalons and the reflections were vanquished. Unfortunately, transmission was cut way down so I essentially couldn't use lucky imaging to break through the seeing (from 6ms exposure with 249 gain to 13ms with 350 gain, basically getting into grainy images). I had to eyeball the exposures as the histogram wouldn't load for some reason.

There was some increase in contrast for the triple stack but too great a loss in transmission to be worth it to me in this configuration. Visual impression was similar.

Below are the results:

Double stack (6ms 263 gain (65%) 158fps)

Image

Triple stack (12.9ms, 347 gain (86%) 77fps)

Image


Double stack (6ms 263 gain (65%) 158fps)

Image


Triple stack (12.9ms, 347 gain (86%) 77fps)

Image


The filter stack. Very important to note here that both Lunt 40mm etalons are in the telecentric output of the quark, which is being used as specified by the manufacturer. The whole imaging train is sun→AT102ED→Baader 35nm H-alpha→ Optolong KG3 UVIR →Quark Chromosphere (with built in 4.2x telecentric --> Lunt etalon 1→Hoya circular polarizer HRT 52mm→ Lunt etalon 2 → tilt adapter →>AS174MM. Lunt etalons are housed in the Raf camera adapters.

Image

Bonus full disk - Lunt 40mm double stack with 174MM, very under sampled
Image

I will keep fiddling with the setup to see if I can improve results.

Best,
Derek


User avatar
marktownley
Librarian
Librarian
Posts: 42274
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 20442 times
Been thanked: 10247 times
Contact:

Re: March 12, 2023 102mm double and triple stack comparison with bonus full disk

Post by marktownley »

Ingteresting results Derek, I think i'd probably stick with double stack in this instance.

Try and see which of the lunt etalons gives the best result (singly) with the Quark, one will be better than the other.


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!
Dennis
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 1668
Joined: Sat Apr 27, 2019 6:44 pm
Location: Germany
Has thanked: 2978 times
Been thanked: 2082 times

Re: March 12, 2023 102mm double and triple stack comparison with bonus full disk

Post by Dennis »

Very nice comparison, thx. So doublestack seems to be the sweetspot.


Triband C9.25
H-a: Quark Chromosphere with BF mod
WL: Antlia 500nm/ 3nm, 393 nm/ 3nm
Ca-K: homebrew (includes 2x 1.5A filters, thanks Apollo)
Player One Apollo Max + Mars MII
Barlows:
-2x Gerd Düring 2.7x
-2x TMB 1.8x
User avatar
ffellah
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 11172
Joined: Mon Oct 27, 2014 6:46 pm
Location: Westport, CT USA
Has thanked: 9145 times
Been thanked: 6025 times

Re: March 12, 2023 102mm double and triple stack comparison with bonus full disk

Post by ffellah »

Excellent ! The last one of the closeups in my opinion looks best. Pretty amazing contrast and clarity: maybe it is also the processing.

Franco


User avatar
Averton
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 1775
Joined: Wed Jun 01, 2022 1:35 pm
Has thanked: 3303 times
Been thanked: 2312 times

Re: March 12, 2023 102mm double and triple stack comparison with bonus full disk

Post by Averton »

Very interesting experiment Derek.
We would agree that over 300 gain for the 174MM is bad territory. Even with our DS similar arrangement we are scraping on occasion to get enough photons to the sensor. It becomes a compromise of either too much gain or too long an exposure, neither giving us a good outcome.


Clare & Peter
Oak
Ohhhhhh My!
Ohhhhhh My!
Posts: 142
Joined: Mon Feb 07, 2022 6:16 pm
Has thanked: 288 times
Been thanked: 232 times

Re: March 12, 2023 102mm double and triple stack comparison with bonus full disk

Post by Oak »

Thanks all,
Yes double stack seems to be the sweet spot for now. I want to try a focal reducer and perhaps a different orientation of the polarizer (although I'm pretty sure I got it right this time given the polarized output of the quark)


User avatar
marktownley
Librarian
Librarian
Posts: 42274
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 20442 times
Been thanked: 10247 times
Contact:

Re: March 12, 2023 102mm double and triple stack comparison with bonus full disk

Post by marktownley »

I'm not sure there will be much to gain even if you could get the exposure shorter (through focal reducer or changing orientation of polariser) - there's little difference in the bandwidth tightening between double and triple stacking in this instance, it's just etalon synergy. I would try clocking the 2 lunt etalons relative to each other first to see if that improves things in this case.


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
Carbon60
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 14209
Joined: Wed Mar 07, 2012 12:33 pm
Location: Lancashire, UK
Has thanked: 8418 times
Been thanked: 8163 times

Re: March 12, 2023 102mm double and triple stack comparison with bonus full disk

Post by Carbon60 »

Nice experiment, Derek. I’ve triple stacked my Lunt 60, but it’s really tricky getting all three etalons to work together to effectively reduce the bandpass. Given there’s no discernible difference between your DS and TS images other than noise, I would suggest the tuning is out of step between the three units. TS is really only working as a DS in other words.

I guess the question is, does the potential gain outweigh the loss resulting from image noise and slower exposures? For FDs I’ve found a significant improvement with triple stacking my particular etalons, but on a Lunt 60 with a 2.5x PM for FD mosaics the increased exposure time makes no significant difference to the resulting image.

Stu.


H-alpha, WL and Ca II K imaging kit for various image scales.
Fluxgate Magnetometers (1s and 150s Cadence).
Radio meteor detector.
More images at http://www.flickr.com/photos/solarcarbon60/
Oak
Ohhhhhh My!
Ohhhhhh My!
Posts: 142
Joined: Mon Feb 07, 2022 6:16 pm
Has thanked: 288 times
Been thanked: 232 times

Re: March 12, 2023 102mm double and triple stack comparison with bonus full disk

Post by Oak »

Good points. I will work on tuning and rotation first. I did some rotation in my previous attempt and didn't see a difference.


User avatar
arnedanielsen
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 7285
Joined: Fri Apr 18, 2014 10:42 pm
Location: Vestby, Norway
Has thanked: 6181 times
Been thanked: 7142 times

Re: March 12, 2023 102mm double and triple stack comparison with bonus full disk

Post by arnedanielsen »

Interesting experiment and very nice results!

Best regards,
Arne


Best regards,
Arne
--
AstroBin: https://www.astrobin.com/users/arnedani/
User avatar
Peterm
Almost There...
Almost There...
Posts: 1179
Joined: Tue Nov 22, 2022 2:17 am
Location: Australia, Gold Coast, QLD
Has thanked: 1733 times
Been thanked: 1488 times

Re: March 12, 2023 102mm double and triple stack comparison with bonus full disk

Post by Peterm »

Superb images Derek. Congratulations on the SPOD! BravO!


Lunt 80Tha S/S & D/S / B1800; Quark Chromosphere; SkyWatcher 120 Evostar; Celestron SE6; Celestron AVX; Berlebach Planet; ZWO174MM & 432MM & 533MM; Powermate 5X; Lunt Solar Wedge; Hinode SG; Airy Labs SSM

Astrobin: https://www.astrobin.com/users/PeterM/
BOSS team: www.bosssupernova.com
User avatar
DeepSolar64
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 18823
Joined: Thu Sep 05, 2019 12:19 am
Location: Lowndesville S.C.
Has thanked: 17572 times
Been thanked: 16694 times

Re: March 12, 2023 102mm double and triple stack comparison with bonus full disk

Post by DeepSolar64 »

Nice SPOD, Derek!!


Lunt 8x32 SUNoculars
Orion 70mm Solar Telescope
Celestron AstroMaster Alt/Az Mount
Meade Coronado SolarMax II 60 DS
Meade Coronado SolarMax II 90 DS
Meade Coronado AZS Alt/Az Mount
Astro-Tech AT72EDII with Altair solar wedge
Celestron NexStar 102GT with Altair solar wedge
Losmandy AZ8 Alt/Az Mount
Sky-Watcher AZGTI Alt-Az GoTo mount
Cameras: ZWO ASI178MM, PGR Grasshopper, PGR Flea
Lunt, Coronado, TeleVue, Orion and Meade eyepieces

Image Visual Observer
" Way more fun to see it! "
User avatar
marktownley
Librarian
Librarian
Posts: 42274
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 20442 times
Been thanked: 10247 times
Contact:

Re: March 12, 2023 102mm double and triple stack comparison with bonus full disk

Post by marktownley »

Oak wrote: Wed Mar 15, 2023 11:03 am Good points. I will work on tuning and rotation first. I did some rotation in my previous attempt and didn't see a difference.
Other one to try is reversing the order of the lunt etalons, in addition to clocking them.


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
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: 4787 times
Contact:

Re: March 12, 2023 102mm double and triple stack comparison with bonus full disk

Post by MAURITS »

Nice comparation Derek, congrats on SPOD 👍


Regards,
Maurits

Vista del Cielo Observatory

www.vistadelcielo.be
Post Reply