Six days with PST

this is the main message area for anything solar :)
Post Reply
Astrophil
Almost There...
Almost There...
Posts: 903
Joined: Thu Dec 20, 2018 2:00 am
Been thanked: 581 times

Six days with PST

Post by Astrophil »

The skies were reasonably clear last week and the Sun's surface features were still rather uneventful so I took the opportunity to image with the PST double stacked. The objective was to consistently produce an acceptable full disk image with detail over at least most of the surface and devoid of the usual hot spot which required a lot of post processing to control.

I re-read the recent posts pertaining to PST imaging and searched through old ones. While most suggestions dealt with tuning between the etalons and adjusting tilt, which I found very difficult to determine on band with a blank sun, other suggestions mentioned placement of the disk in the field and rotating components. I would try them all. I had previously removed the black box from the PST and set it up for straight through imaging. All components could be rotated individually.

To make a short story longer picture this. The front etalon, the tilt mechanism, the main etalon, blocking filters, and camera. All can effect the image and all are interrelated. So, five degrees of freedom for a non optical engineer to contend with. After a while it was determined that the rotation between the front etalon and tilt mechanism was unnecessary as was the main etalon rotation in relation to the objective lens (optical tube). Both were tightened to their original positions. This simplified things a little.

Monitoring a high contrast, over exposed image on the computer screen, the solar disk was kept centered on the hot spot (sweet spot?). While making rotational adjustments to the double stack the spot could be moved closer to the center of the field. Minimum tilt was used to move the reflection just off field. Camera rotation helped as well. The PST eyepiece holder with the blocking filters still intact was rotated and the obnoxious glow off to one side of the disk was reduced somewhat. Progress.

Tuning the etalons on this double stacked PST was done by slowly rotating the main etalon counter clockwise in steps and adjusting the double stack to increase the intensity of the hot spot. Luckily there was a bright region near the limb to watch. Exposure was adjusted to maximize visibility. When contrast between the surface and the active region appeared the best, I centered the disk on the hot spot, lowered exposure and contrast, and hit record.

Unfortunately, these adjustments did not completely eliminate the brighter center produced by this PST and post processing was still required. I decided to use a flat frame to help with uniformity. A diffusing material was placed over the front of the scope and exposure time was increased along with gain to approximately match the original histogram. With this diffuser the exposure needed to be increased to 1 sec. That produced a noisy flat and was median filtered before applying. Minimum post processing was required for field illumination but now I notice Newton rings that I had not seen before.

The attached test images represent six days imaging with a double stacked PST. The last three images were flat corrected.

Phil

20191001_110836_acm.jpg
20191001_110836_acm.jpg (419.3 KiB) Viewed 1825 times
20191002_095133_acm.jpg
20191002_095133_acm.jpg (408.53 KiB) Viewed 1825 times
20191003_135633_acm.jpg
20191003_135633_acm.jpg (403.07 KiB) Viewed 1825 times
20191004_121510_combo_cc.jpg
20191004_121510_combo_cc.jpg (618.34 KiB) Viewed 1825 times
20191005_125217_combo.jpg
20191005_125217_combo.jpg (351.13 KiB) Viewed 1825 times
20191006_101605_combo_afc.jpg
20191006_101605_combo_afc.jpg (407.35 KiB) Viewed 1825 times


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: 10244 times
Contact:

Re: Six days with PST

Post by marktownley »

You got a nice set there Phil.


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
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: Six days with PST

Post by MalVeauX »

Pretty cool Phil, and good details are definitely seen! I think you have it dialed in as much as it can be.

Very best,


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: Six days with PST

Post by Starry Jack »

Really clean!


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
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: Six days with PST

Post by MAURITS »

Nice story Phil, well done.


Regards,
Maurits

Vista del Cielo Observatory

www.vistadelcielo.be
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: Six days with PST

Post by Montana »

Well done Phil, these are terrific :bow you worked really hard to achieve the best possible results :hamster:

Alexandra


User avatar
Martin_S
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 1839
Joined: Sat Mar 16, 2019 12:34 am
Location: Brisbane , Australia
Has thanked: 979 times
Been thanked: 2992 times

Re: Six days with PST

Post by Martin_S »

Great Imaging Phil. well done

Martin


H alpha : ,Skywatcher 120mm F8 open frame refractor, a tilted 2" 7nm H-alpha filter as a sub energy rejection filter, Baader TZ4 telecentric focal extender, Player One energy rejection filter, Combo Quark Chromosphere, Naked PST etalon for double stacking, ASI74mm camera
Astrophil
Almost There...
Almost There...
Posts: 903
Joined: Thu Dec 20, 2018 2:00 am
Been thanked: 581 times

Re: Six days with PST

Post by Astrophil »

Thank you all for the kind comments.
Mark, your encouragement is always well received.
Marty, I much appreciate your practical solutions to problems. Most recently the cereal bag flat and source for the adapter to put this together.
Alexandra, the spectacular PST images you present really serve as a guide and a goal for us beginners.
And to all the other members here who provide knowledgeable and unpretentious advice, thanks.

So now, to gild the lily before retiring the PST, awaiting a more active Sun, here's the final take from October 6th.

Phil


.
20191006_100718_acm.jpg
20191006_100718_acm.jpg (387.04 KiB) Viewed 1756 times


User avatar
Carbon60
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 14205
Joined: Wed Mar 07, 2012 12:33 pm
Location: Lancashire, UK
Has thanked: 8415 times
Been thanked: 8161 times

Re: Six days with PST

Post by Carbon60 »

Excellent work, Phil.

Your persistence and hard work paid off. Lovely FDs

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/
User avatar
ffellah
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 11171
Joined: Mon Oct 27, 2014 6:46 pm
Location: Westport, CT USA
Has thanked: 9144 times
Been thanked: 6025 times

Re: Six days with PST

Post by ffellah »

Lovely results, Phil.

Franco


User avatar
MapleRidge
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 10199
Joined: Fri Jan 13, 2012 11:58 pm
Location: Cambray, ON Canada
Has thanked: 64 times
Been thanked: 4340 times
Contact:

Re: Six days with PST

Post by MapleRidge »

Superb series of full disk images Phil...excellent work :bow

Brian


Brian Colville

Maple Ridge Observatory
Cambray, ON Canada

Photos: https://www.flickr.com/photos/185395281@N08/albums

10'x15 Roll-off Roof Observatory
Takahashi EM400 Mount carrying:
C14 + Lunt 80ED
Deep Sky Work - ASI294MM Pro+EFW 7x36/Canon 60D (Ha mod), ONAG
Planetary Work - SBIG CFW10, ASI462MM

2.2m Diameter Dome
iOptron CEM70G Mount carrying:
Orion EON 130ED, f7 OTA for Day & Night Use
Ha Setup: Lunt LS80PT/LS75FHa/B1200Ha + Home Brew Lunt Double Stack/B1800Ha on the Orion OTA + Daystar Quantum
WL, G-Band & CaK Setup: Lunt Wedge & Lunt B1800CaK, Baader K-Line and Altair 2nm G-Band filter
ASI1600MM, ASI432MM, ASI294MM Pro, ASI174MM, ASI462MM
User avatar
hopskipson
Im an EXPERT!
Im an EXPERT!
Posts: 328
Joined: Sun Jan 13, 2019 9:27 pm
Location: Queens, NY
Has thanked: 408 times
Been thanked: 191 times

Re: Six days with PST

Post by hopskipson »

Nice images!

I’m jealous you got 6 days in a row to image.


James
These pretzels are making me thirsty! (C.C.)
The Quark introduced me to this wonderful side of the hobby and the sun hasn’t disappointed yet.
Solar Equipment: Solar Spectrum RG-18 0.3A, Coronado Solarmax 90mm etalon Isle of Man SN-001, Tuscon SN-380 and Meade SM2, Lunt LS80 DS, Quark Chromosphere, Lunt 2" wedge, 2-Lunt CaK II 1200, Baader 3.8 and 5.0 solar film in 208mm cells, and 3D printed Sol'Ex SHG, Lunt 40mm
Coming Soon: Solar Spectrum CaK II <1A filter
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: Six days with PST

Post by eroel »

Phil:
Clean and sharp FD´s, the result of hard work tweaking the filters to their best position.
I don't know if you already got to the point that gives you the best adjustments with the scope pointing East, but when you go to the West side you loose the adjustment. Here you try to get the best adjustment possible E and W, or you try to image just on one side with the best adjustment possible, that is why I just image at home before lunch :roll:
Best regards,
Eric.


Astrophil
Almost There...
Almost There...
Posts: 903
Joined: Thu Dec 20, 2018 2:00 am
Been thanked: 581 times

Re: Six days with PST

Post by Astrophil »

Thanks Stu, Franco, Brian, and James. Six days in a row was exhausting, I had to take the next day off.
Eric, interesting info. I too image before lunch. Too many obstacles in the afternoon.

Phil


Post Reply