PST Etalon with a Quark, Log & Results

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PST Etalon with a Quark, Log & Results

Post by MalVeauX »

Hello,

I'm looking for some info, a user (Jozef) hasn't been active in over 6 months on the forum so I'm not sure a message would reach them. However, they were using a Quark (with 4.2x telecentric internal and intact) with a 2" eyepiece adapter and inserted a PST etalon into the eyepiece of the Quark, and then a camera into the back of that, with adapters. I know others have done this too. Some with success. Some without.

I have the parts just laying around, so I figure, why not try it out? Who knows, maybe I have some decent stuff to pair up, or maybe this is just an exercise in tinkering that will result in nothing but information and no images. That's ok too.

A few questions of course, to help rip this thing apart...

I'm wondering if I have to remove any lenses or anything from the PST etalon. I have removed the brass tube and the black box and have the etalon housing itself intact. I have the adapters front & back from AOK swiss. Can this be inserted into a 2" eyepiece Quark like this and then a camera in the other end and function? This seems to be what Jozef was doing and it worked. But I'm not sure if anything was removed from the etalon housing of the PST.

Thanks!

+++++++++++++++++++++++++
+++++++++++++++++++++++++

Harvesting the PST etalon:

Naturally I would test this myself. But, as the old curse goes, the moment my adapter showed up in the mail today and I was able to disassemble the PST housing successfully, a big pile of stormy dookie has been sitting over me, all day. All day. "Sunny Florida."

Here's the disassembly of my PST:
PST_remove_from_blackbox.jpg
PST_remove_from_blackbox.jpg (34.78 KiB) Viewed 11071 times
PST_remove_etalon_housing_from_brasstube_blackbox.jpg
PST_remove_etalon_housing_from_brasstube_blackbox.jpg (61.19 KiB) Viewed 11071 times
And of course.... the resulting immediate weather secondary to this.
GodDamnWeatherYUP12132018.jpg
GodDamnWeatherYUP12132018.jpg (19.61 KiB) Viewed 11071 times
Very best,
Last edited by MalVeauX on Fri Dec 14, 2018 4:17 pm, edited 3 times in total.


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Re: PST Etalon (Mod) Question, with a Quark

Post by bart1805 »

You will have to remove both lenses of the PST etalon.


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Re: PST Etalon (Mod) Question, with a Quark

Post by MalVeauX »

So I need to remove both collimating lenses from both sides? Leave only the etalon?

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Re: PST Etalon (Mod) Question, with a Quark

Post by Merlin66 »

Marty,
Yes....
In the configuration you're proposing the bare etalon will be sitting in the collimated/ telecentric beam at around f30-f40.


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Re: PST Etalon (Mod) Question, with a Quark

Post by marktownley »

I've done the same Marty.


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Re: PST Etalon (Mod) Question, with a Quark

Post by MalVeauX »

Ok thanks all,

So confirming, I remove both the front collimating lens and the back collimating lens from the etalon housing, leaving just the etalon in the mechanical pressure tuner housing with no lenses or anything on either side.

Very best,
Last edited by MalVeauX on Fri Dec 14, 2018 4:17 pm, edited 1 time in total.


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Re: PST Etalon (Mod) Question, with a Quark

Post by bart1805 »

Yep, that's it.


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Re: PST Etalon (Mod) Question, with a Quark

Post by MalVeauX »

Thanks all! :bow

Because I have this setup now and I'm ready to put it to use, it's naturally raining... for the past 6+ hours so far, and a massive storm system is hovering over my entire state (Florida). The curse is real...

++++++++++++++++++++++++++++
++++++++++++++++++++++++++++

More Harvesting of the PST Etalon (removing the collimating lenses):

Objective side, collimating lens:
PST_collimatinglens_ToObjectiveSide.jpg
PST_collimatinglens_ToObjectiveSide.jpg (60.52 KiB) Viewed 11007 times
Eyepiece side, collimating lens:
PST_collimatinglens_ToEyepieceSide.jpg
PST_collimatinglens_ToEyepieceSide.jpg (46.72 KiB) Viewed 11007 times
Objective side, collimating lens removed:
Collimatinglens_objectiveside_removed.jpg
Collimatinglens_objectiveside_removed.jpg (62.35 KiB) Viewed 11007 times
Eyepiece side, collimating lens removed:
Collimatinglens_eyepieceside_removed.jpg
Collimatinglens_eyepieceside_removed.jpg (67.34 KiB) Viewed 11007 times
Bare PST etalon, objective side:
barePSTetalon_objectiveside.jpg
barePSTetalon_objectiveside.jpg (56.43 KiB) Viewed 11007 times
Bare PST etalon, eyepiece side:
barePSTetalon_eyepieceside.jpg
barePSTetalon_eyepieceside.jpg (40.4 KiB) Viewed 11007 times
Very best,
Last edited by MalVeauX on Fri Dec 14, 2018 4:18 pm, edited 2 times in total.


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Re: PST Etalon (Mod) Question, with a Quark

Post by Valery »

Marty,

Relax, please. After a deal, I will send you the sketch and photos of how to make this system work.

Just remind me then.

Valery


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Re: PST Etalon (Mod) Question, with a Quark

Post by MalVeauX »

Again, I already have this stuff just laying around, so this is an experiment to see what can result from it. Maybe nothing. Maybe something.

I will likely use this with my 150mm F8 refractor and Quark until my next system is assembled and ready for use. I'd do it right now, but it's still raining and this storm will be here a few more days. Bunch of nasty weather coming from the West right now. Ugh.

150mm ERF (already have this) -> 150mm F8 Refractor -> 2" UV/IR Baader Filter -> Extensions -> Quark Chromosphere (4.2x telecentric) + 2" eyepiece holder -> bare PST etalon housing with front/rear adapters -> 2" 0.5x focal reducer -> ASI174MM

This is the imaging train I'm thinking of trying. I have all of it. Just waiting to see if I can get focus and how this etalon performs in the train when the storm passes... And if it doesn't work, not a big deal, I'll use the etalon for other projects or reinstall it back into my PST and go back to just using the PST as I was before. No biggie. But, if it works.... well, then who knows!

Similar to this configuration which I've seen the images its produces:

viewtopic.php?t=17466#p171648

+++++++++++++++++++++++++++
+++++++++++++++++++++++++++

PST Etalon Housing without Collimating Lenses, reinstalled Tuning system, Installed AOK Front/Rear Adapters:

The adapter by Beat Kholer over at AOK Swiss are excellent, they fit perfectly, and they're very friendly nice chaps over there. Inexpensive for the adapters and fast shipping. Really great, and I highly recommend them if you're looking to do a PST mod of some kind.
pst_AOKadapters.jpg
pst_AOKadapters.jpg (46.09 KiB) Viewed 10988 times
And of course, because I'm ready to play around and test a few things, see if anything even remotely works, here's what I get:

:lol: :oops:
Storms_GOGOGO.jpg
Storms_GOGOGO.jpg (33.84 KiB) Viewed 10987 times
Very best,


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Re: PST Etalon with a Quark, Log & Results

Post by MalVeauX »

Playing around with some configurations to test fittings, how tight everything is, weight, etc. Pretty heavy! Very substantial weight for an imaging train and will create a significant moment arm I imagine.

Here's the Quark with 2" eyepiece holder next to the PST etalon with its adapters:
Quark_PSTEtalonAdapters.jpg
Quark_PSTEtalonAdapters.jpg (22.16 KiB) Viewed 10982 times
Here's the Quark with 2" eyepiece holder with the PST etalon installed into its 2" eyepiece with adapters next to an ASI174MM with a 2" focal reducer:

The focal reducer fits into the chamber, but the ring I'm using to attach the focal reducer to the camera's threading bulges out ever so slightly and doesn't fit into the chamber without force, so I may change this ring out or find another way to mount a focal reducer, or change out the rear assembly....
Quark_PST_ASI174MM_FocalReducer.jpg
Quark_PST_ASI174MM_FocalReducer.jpg (23.66 KiB) Viewed 10982 times
Here's the Quark with 2" eyepiece holder, PST etalon with adapters installed, ASI174MM fit into the rear adapter (without focal reducer):

I have a strong feeling that this rear adapter is too long and will not be suitable for imaging. More suitable to a 2" diagonal. I think the camera will have to be closer. I'm not positive of course until I get a sunny day. Hrm....
Quark_PST_CameraInstalled.jpg
Quark_PST_CameraInstalled.jpg (28.88 KiB) Viewed 10982 times
I'll have to of course also test whether a tilt adapter will work in this arrangement some where. Usually I can take out newtonian rings with a flat frame. But, I'm not sure how bad they will be in this setup yet. Still raining....

++++++++++++++++
++++++++++++++++

Now that I've even touched these things, I had to make sure I didn't just cause a tropical cyclone to be born... so I took a look over at the hurricane watch satellite image to make sure... :lol: :lol:
stormwatch.jpg
stormwatch.jpg (51.13 KiB) Viewed 10982 times
Very best,


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Re: PST Etalon with a Quark, Log & Results

Post by MalVeauX »

Hello,

I have an update and first light. The image will merely represent proof of concept in that it's working and not at unreasonable settings. I had to test and attempt a little imaging through clouds today (of course, right?), so I didn't spend a lot of time and will wait for a clear day to attempt anything serious. For now, this is enough to show proof of concept and that it works.

Here's the setup on my 150mm F8 refractor:

I'm using 195mm extensions currently and can achieve focus no problem. The Quark has a 2" eyepiece holder installed. I'm using the AOK adapters, front & rear, without modification to them and that holds the PST etalon housing without collimating lenses. This inserts into the Quark's 2" eyepiece holder and is secured there. I used a 1.25" adapter in the 2" eyepiece holder side of the PST rear adapter and inserted an ASI174MM camera with a 1.25" nose installed and a 1.25" 0.5x GSO focal reducer on the end of that. I was able to still achieve focus no problem.
DS_Quark_PST_02.jpg
DS_Quark_PST_02.jpg (31.07 KiB) Viewed 10850 times
DS_Quark_PST_01.jpg
DS_Quark_PST_01.jpg (25.52 KiB) Viewed 10850 times
SolarSetup_12172018.jpg
SolarSetup_12172018.jpg (39.84 KiB) Viewed 10850 times
It was very cloudy, I did not have transparency at all, so this was for a brief few seconds with clouds moving through it.

I was able to get this at 10ms, 120 gain at F17 with both the Quark & PST Etalon together after tuning them to a uniform image.

There is no flat calibration applied here either. I did crop away vignetting from the focal reducer and merely showing the AR (there was much more in the FOV). This is merely to show that it's working, focuses, and tunes together well and is on band and happy. I'm totally fine imaging at 120 gain at 10ms at this image scale. However, again, this was through clouds. Without clouds, this will be much lower gain. It seems this Quark and this PST etalon have good transmission levels.

I do not think this capture represents anything more narrow than what my Quark achieves on its own with an F35~F40 beam. But, I didn't expect to effect my bandpass at the most narrow side. I didn't get to image it yet, but I briefly saw the limb between cloud bursts, and the double-limb suppression was pretty clear, so if anything, the PST etalon is helping shave the skirt around the transmission profile of the Quark's bandpass. My main goal is to simply eliminate the double limb. So I hope to show that soon when the storms pass and the clouds let up.

I will update with limb images as soon as the clouds clear, to really show if this suppresses the skirt and takes out the continuum double limb.

This image merely represents that focus was possible with a focal-reducer, and that transmission is acceptable for imaging.

AR12731 from today.
AR_01_BW.jpg
AR_01_BW.jpg (151.35 KiB) Viewed 10850 times
Very best,


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Re: PST Etalon with a Quark, Log & Results

Post by MalVeauX »

Update,

I had some clear sky this morning so I was able to test a few things. I tested more configurations and rotations. It definitely behaves like polarized light between the two etalons, as every 90 degree turn results in black out, while at two spots opposite each other in the rotation light passes through and they tune the same at both spots. Interesting enough. I was able to get some limb data and a some data on AR2731 again. I tried a few scales just to test the transmission level and all that.

I added an ST80 to the mix, with a 60mm aperture mask. I like the idea of being able to move the Quark & PST etalon system from one scope to another, without much effort or time, and image at two scales quickly. I tested this by doing some partial discs, and attempted a full disc mosaic with 4 panels captured & stitched. I wasn't able to do a flat calibration frame on the smaller scale due to not filling the FOV with the disc, with the focal reducer.
SolarSetup_150mm_12182018.jpg
SolarSetup_150mm_12182018.jpg (59.23 KiB) Viewed 10788 times
ST80_Piggyback.jpg
ST80_Piggyback.jpg (38.63 KiB) Viewed 10788 times
DoubleRefractor_DoubleStack.jpg
DoubleRefractor_DoubleStack.jpg (38.1 KiB) Viewed 10788 times
Today's Results;

150mm Refrator
Here's AR2731 with the 0.5x focal reducer:
10ms, Gain 95
Flat calibrated

Image

Image

150mm Refractor
Here's AR2731 without the focal reducer (larger scale, over-sampled):
10ms, Gain 205
Flat calibrated

Image

Image

150mm Refractor
Still learning how to expose & process the limbs, it's not the same now.
10ms, Gain 100
Flat calibrated

Image

150mm Refractor
10ms, Gain 115, Gamma Max
Flat calibrated

Image

ST80 (masked to 60mm) Refractor
10ms, Gain 50, Gamma Max
Pseudo flat in post (still figuring this out)

Image

ST80 (masked to 60mm) Refractor
10ms, Gain 50m Gamma Max (Mosaic of 4 panels)
Pseudo flat in post, made after stitching

Image

Color versions:

Image

Image

Image

Image

Image

Image

Image

Very best,


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Re: PST Etalon with a Quark, Log & Results

Post by Merlin66 »

Marty,
Any update??


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Re: PST Etalon with a Quark, Log & Results

Post by MalVeauX »

Attempted some data today,

I am definitely challenged by the new approach to acquire data and process it without destroying the limb. It's probably not as tight as a much more expensive double stack system, but it's tighter than a single stack for sure.

I am currently challenged with how to acquire data. Whether to expose with maximum gamma, or no gamma, or a combination. And then later, how to pull up the delicate prominences & spicules, or how not to destroy the transition at the limb and lose it when recovering contrast. I attempted two ways today, both maximum gamma and zero gamma, and both presented with challenges. With max gamma, I am challenged in recovering contrast on the disc surface. With no gamma, I find it much harder to retrieve the spicules & prominences and find the limb suppressed of detail while there is high contrast on the surface.

Seeing was really bad today, despite high transparency and no clouds. Sigh.

+++++++++++++++++++++
+++++++++++++++++++++

Full disc mosaic made with the ST80 (400mm F5) masked to 60mm (F6.67) with the Quark & PST etalon.

Image

Image

Full scale of the 150mm F8 with the Quark & PST etalon, no focal reducer used, grossly over-sampled, AR2731 as it rotates the limb:

Image

Image

Image

Image

And here's a really weird example of trying to manipulate the data to keep the limb and contrast without losing the spicules & proms, but this is where I'm challenged the most and need to figure out how to process this data better.
Test data
Test data
MaxGammaTest.jpg (154.23 KiB) Viewed 10704 times
++++++++++++++++++++++
++++++++++++++++++++++
solarsetup12222018.jpg
solarsetup12222018.jpg (91.94 KiB) Viewed 10704 times
Very best,


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Re: PST Etalon with a Quark, Log & Results

Post by marktownley »

Personally, I always go for zero gamma.


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Re: PST Etalon with a Quark, Log & Results

Post by Bob Yoesle »

I agree Mark. I use minimal gamma in my capture process, generally underexpose, and bring out almost everything in post-capture processing.

Marty PM'd me about this possibly being a double limb issue, but it doesn't look like it to me. The last image looks pretty good at the center of the disc, but the limb is really weird - becomes soft if not blurry, and contrast seems to go out the window, and there is no sharp photospheric boundary, etc. I suggested he try reduced gamma and perhaps different capture and stacking software...


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Re: PST Etalon with a Quark, Log & Results

Post by marktownley »

Bob Yoesle wrote: Sun Dec 23, 2018 7:34 am The last image looks pretty good at the center of the disc, but the limb is really weird - becomes soft if not blurry, and contrast seems to go out the window, and there is no sharp photospheric boundary, etc. I suggested he try reduced gamma and perhaps different capture and stacking software...
Have you used 'shadows and highlights' in your post processing Marty? This is an artefact that this can produce.


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Re: PST Etalon with a Quark, Log & Results

Post by MalVeauX »

I'm going to try more without gamma and switch to FireCapture.

I have tried Shadows&Highlights in Photoshop. On the same images that if I pushed gamma, I would see the proms clearly, when I don't use gamma and simply use Shadows&Highlights, the proms do not lift nearly as clearly. This makes me wonder what "gamma" really is in SharpCap. So I'm switching to FireCapture today to see if there's a difference in acquisition and will move towards no-gamma or minimal gamma if possible.

I will also try to use AS!3 and Registax6 to stack instead of AS!2 to see if it makes a difference on the limb.

Here's another weird example of the limb and proms with gamma use:
Example_Limb_Prom.jpg
Example_Limb_Prom.jpg (78.29 KiB) Viewed 10651 times
Here's zero gamma use, stacked, then trying to lift proms the same exposure just minus gamma in acquisition:
NoGammaLimb_AteTheSpicules.jpg
NoGammaLimb_AteTheSpicules.jpg (83.18 KiB) Viewed 10651 times
When I lift this one, the limb is bare, and the proms are barely there without definition. The same capture with gamma use shows a lot more. So I'm confused what gamma is doing in SharpCap, if it's just artificial, but I cannot even push gamma in post and see the same thing it does when I'm using it real time in SharpCap.

Very best,


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Re: PST Etalon with a Quark, Log & Results

Post by MalVeauX »

Update,

I grabbed data this morning, single stack & double stack. I started using FireCapture. Worked out my learning curve but got some data. I have to say, I'm a total numpty for not moving to FireCapture sooner. I also used AS!3 this time. I did not use gamma (unchecked the box). It looked so different in the preview window than I'm used to. Even though gamma was off, I was able to see proms & surface in the same exposure just filling the histogram. My main interest was the limb of course to see if my tuning was on band with both and if the double limb was taken out.

Here's the result from the double stack Quark & PST tuned together, no gamma, just a flat frame, and some minor sharpening of this morning's prominence & limb. I feel the limb spicules alone are a big change, and that AS!3 did a much better job of preserving that. FireCapture made it a lot easier to get the data without gamma too.

I still think I over-exposed as my disc is bright and when I compress mid-tones I lose the limb & proms. I think this is a processing issue on my part that I'll work through.

I'll update with more as I process through this stuff.

Thanks all!
PromSurf_DS_OneExposure_NoGamma.jpg
PromSurf_DS_OneExposure_NoGamma.jpg (78.58 KiB) Viewed 10626 times
I was playing with processing. I found that if I used Shadows&Highlights to reduce highlights while pushing up shadows, I was able to find a more happy flat medium between the two, gaining some contrast back.

Image

Image


I feel like I still have a long way to go with this setup, but this is at least improvement from before.

I may have been off-band a bit with one of the tuners (the PST one at least I tuned, I don't tune the Quark, it's already set). I still feel like I'm seeing a bit of the double limb, but I'm not sure if it's my processing or what.

I need to spend more time making sure both etalons are perfectly on band together. Yesterday I was able to see crazy contrast on a filament and that helped a lot. Today I didn't have such a feature to work on and mostly just looked for increased contrast near the limb around spicule bundles as they would pop in and out of high contrast and just used that.

++++++++++++++++++++++++++
++++++++++++++++++++++++++

Here's a look at the contrast I'm getting on spicules near AR2731 that I used to help figure if I was tuned on band or not.
ContrastExample.jpg
ContrastExample.jpg (126.51 KiB) Viewed 10617 times
++++++++++++++++++++++
++++++++++++++++++++++

Here's an example of the limb with only the Quark, single stack, no PST etalon used. The double limb is very obvious of course. I just wanted to test and compare.
SingleStack_Limb.jpg
SingleStack_Limb.jpg (73.28 KiB) Viewed 10610 times
And here's the Quark & PST etalon together again.

I can still see a bit of the double limb. I'm not sure if it's due to tuning. Or maybe it just isn't able to suppress the skirt. It's less obvious, but it's still something I can see.
DoubleStack_Limb.jpg
DoubleStack_Limb.jpg (95.26 KiB) Viewed 10610 times
+++++++++++++++++++++++++
+++++++++++++++++++++++++

FireCapture made quite a difference in capturing and doing flat calibration. Using the same exposure values that I used to use in SharpCap, normally I would see a contrasty surface, but no limb/proms. In FireCapture I'm seeing limb/proms with the same exposure values. I'm not sure the difference. Drivers? I have gamma unchecked, so it's neutral. But it looks like how it looked in SharpCap with Gamma turned up. Granted, the results are significantly different. Still not perfect. But I'm still learning to use new software. And I have to re-learn processing this kind of data differently. AS!3 I think did a better job keeping the limb and spicules. I can't get Registax to handle my files, maybe they're too big.

Very best,


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Re: PST Etalon with a Quark, Log & Results

Post by Bob Yoesle »

Hi Marty,

Much improved! Yeah, you still have a little double limb. Could be a PST etalon tuning issue. And to my eye still a little soft towards and at the limb - but still much better ;-)

How big is the above double stack video file? Perhaps if you can uploaded it to Dropbox, I could download it and try and play with it in RegiStax and see what happens...


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Re: PST Etalon with a Quark, Log & Results

Post by MalVeauX »

Bob Yoesle wrote: Sun Dec 23, 2018 7:59 pm How big is the above double stack video file? Perhaps if you can uploaded it to Dropbox, I could download it and try and play with it in RegiStax and see what happens...
Yea, I see the limb, I will have to find a way to best tune it. Then again, it may never get rid of the double limb completely, it may not be tight enough in this configuration. I may also have to reconsider how I tune my Quark. I tune my Quark as far to the blue side as possible, so 9'oclock on my Quark, and it has the most contrast there. It may be beyond what the PST etalon can also tune to? I may have to try re-tuning the Quark and then tune the PST to it? This will be quite the project if that's the case. But, if it means no double limb, that's the point hopefully!

4.4Gb (33 seconds), 2000 frames.

I'm on 3G speeds with my air card (I live in the boonies), so even if I shaved it down, it would take a long time to upload some where. But I'd be willing to try something if you have any ideas on how to best shave it down without culling good data.

Very best,


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Re: PST Etalon with a Quark, Log & Results

Post by marktownley »

That first image is nice - try running with the same settings but the histogram peaking around 70%. It's easier to stretch an image than squish the histogram back.


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Re: PST Etalon with a Quark, Log & Results

Post by MapleRidge »

Hi Marty...

The double stack is shaping up nicely as you fine tune the settings and processing. Superb work :bow


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Re: PST Etalon with a Quark, Log & Results

Post by Bob Yoesle »

I'm on 3G speeds with my air card (I live in the boonies), so even if I shaved it down, it would take a long time to upload some where. But I'd be willing to try something if you have any ideas on how to best shave it down without culling good data.
HI Marty,

Don't really have any suggestion other than doing the upload at night so it will have minimal bandwidth interference and takes place while you're possibly catching some sleep...


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Re: PST Etalon with a Quark, Log & Results

Post by MalVeauX »

Haven't had good weather lately, just rain and clouds... "Sunny Florida."

Anyhow, got a small break this morning without clouds, so I tested things out.

I tried tuning the Quark & PST Etalon together to maximize contrast on the large filament on the disc today as I figure the darker it got, the more on band I was (maybe this is incorrect?). I couldn't use the limb by itself as a good judge with the poor seeing rippling in and out. So I went for contrast with the AR and filament. Then I slewed to an area to image and judge the limb and the tuning.

I'm still seeing a double limb. I'm guessing so far that while the PST etalon helps shave down the skirt, it's not doing enough, so this may be a bust in terms of keeping it going. While I do get a positive effect from the PST etalon with the Quark, it comes at the price of longer exposure and higher gain values which makes it harder of course. I'm still on the fence with whether I will keep this up, or ditch the PST etalon back into a PST telescope and call it a day there.

Here's the test on the limb from this morning. I filled the histogram to 70% per recommendation to allow a little more room with highlight and shadow recovery and stuff. This is 180 frames stacked, when seeing was quite good.
Test_DS_Limb_Tune.jpg
Test_DS_Limb_Tune.jpg (144.69 KiB) Viewed 9240 times
Another edit to see how things handle when I compress mid-tones, increase contrast and recovery some shadow at the limb:
Test_DS_Limb_Tune_02.jpg
Test_DS_Limb_Tune_02.jpg (53.38 KiB) Viewed 9238 times
Here's another test. Single stack and Double stack to compare the limb at small scale, this was through the ST80 (masked to 60mm):

Single stack (Quark only):
Test_Limb_SS.jpg
Test_Limb_SS.jpg (13.35 KiB) Viewed 9232 times
Double stack (Quark + PST etalon):
Test_Limb_DS.jpg
Test_Limb_DS.jpg (12.04 KiB) Viewed 9232 times
Very best,


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Re: PST Etalon with a Quark, Log & Results

Post by MalVeauX »

Hrm,

So now I'm curious, why use the PST etalon after the Quark? I wonder if I could place it, or a different etalon, in front of the Quark instead? Be it something like a Lunt 35mm, 50mm or other? Also curious if I can simply just put a narrowband filter instead of a 2nd etalon here to shave the skirt?

Just thinking of the results so far, it makes me wonder about the PST etalon as I would think it would easily shave off the skirt of the transmission profile, given the Quark is operating with a tight bandwidth and not see the double limb. But, the limb is there, so it's not achieving what a typical double stack should be able to do. It's helping a little, but it's not taking out the continuum.

Or heck, what about a combo Quark inserted into the other Quark?

Very best,
Last edited by MalVeauX on Tue Jan 01, 2019 9:35 pm, edited 1 time in total.


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Re: PST Etalon with a Quark, Log & Results

Post by marktownley »

If you put a different etalon infront of the Quark it wouldn't be in a telecentric beam and wouldn't work. Quark after Quark won't work - the etalons are polarised and would work to make virtaully zero transmission.


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Re: PST Etalon with a Quark, Log & Results

Post by MalVeauX »

marktownley wrote: Tue Jan 01, 2019 9:07 pm If you put a different etalon infront of the Quark it wouldn't be in a telecentric beam and wouldn't work. Quark after Quark won't work - the etalons are polarised and would work to make virtaully zero transmission.
Interesting thanks,

I saw that Jozef managed to put a Quark & Quark Combo together and posted images. How did that work then? I never saw how the limb looked, just active regions.

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Re: PST Etalon with a Quark, Log & Results

Post by Merlin66 »

Marty,
I find there are PST etalons and there are GOOD PST etalons.
It could be your etalon has a bandwidth <1A ( "Acceptable " to Coronado/ Meade) but wouldn't do much to suppress the "Foot" of the DS bandwidth.
Just a thought.
You could put the lenses back on the PST, set it at the -200mm inside focus and follow it by the Quark...The PST works at f10 so with the x4 in the Quark you'd end up at f40....


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Re: PST Etalon with a Quark, Log & Results

Post by MalVeauX »

Thanks,

That is true, maybe this is a so-so PST etalon.

I decided to try to use it because when I imaged full discs with it, it seemed decent. I was not having issues with surface contrast and filaments were dark and ARs were contrasty. Figured it was at least an ok etalon.

Ex from this etalon when it was in the PST:

Image

Very best,


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Re: PST Etalon with a Quark, Log & Results

Post by Merlin66 »

Marty,
Yeah, that looks good for a PST.....


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Re: PST Etalon with a Quark, Log & Results

Post by MalVeauX »

Do you think there needs to be something after the PST etalon?

I've always though it strange that the train was Quark (with a blocking filter) -> PST Etalon -> no lenses, no glass, no blocking filter -> camera sensor.

It's close to cutting the skirt down, just not quite there.

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Re: PST Etalon with a Quark, Log & Results

Post by george9 »

I use my Lunt DSII unit (intended for an LS80, about 35mm aperture) before my Quark in my 155mm f/7 scope. I cannot visually detect a double limb at all double stacked. With the lone Quark, the double limb is very bright. I estimate my Quark in the 0.5-0.6A range. No idea what the DSII is because I never use it alone.

Therefore, I agree with the above, I would put the collimators back in and place the PST before the Quark. I have two focusers in my rig, so I can adjust the distance of the DSII from the objective and then the Quark from the DSII. I find it is very insensitive to placement of the DSII despite the theory of needing exact placement. So definitely go for it.

Oh, of course I have an ERF (front-mounted DERF) before the DSII unit or I would burn that out.

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Re: PST Etalon with a Quark, Log & Results

Post by george9 »

(I agree after the Quark you would want bare etalon. And before the Quark you need collimation and enough energy reduction but no other blocking. George)


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Re: PST Etalon with a Quark, Log & Results

Post by MalVeauX »

Thanks,

Does the PST etalon require the collimating lenses for a native F10 beam already? Or are they there to create the F10 beam? I'm curious when it comes to putting the PST etalon into a SCT design telescope. I will soon be trying this on my fully blocked C8 Edge, F10, so I could potentially move things around and put the PST etalon (with or without) its lenses first, then the Quark last. Or something different?

I'm also very curious about things like a Lunt etalon. I've seen a few people using them in large scopes, like Harald's unigraph, he's just using a 35mm Lunt etalon and a double stack module with a pressure tuner in some kind of configuration and it seems to cut away that double limb no problem and keeps fairly high transmission. I suppose eventually I'll explore something like the Lunt 35 and Lune 50 etalons. The idea of a double stack using those is not too costly and they are high transmission.

Right now, I'm just trying this out for fun since I already have the Quark and already had the PST.

Very best,


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Re: PST Etalon with a Quark, Log & Results

Post by george9 »

Others are more expert on the PST, but yes I think the lenses you removed are the lenses that allow it to work with the f/10 objective of the PST. So you'll need them if you use the PST etalon before the Quark.

I assume on the C8, you will need the collimating lenses. That's a little more complicated because the beam has already been amplified by the secondary mirror and you will have larger angles than for a native f/10 refractor.

After the Quark, you are over f/30 and don't need the lenses.

The Lunt 35 will require some kind of additional collimating lenses. The DSII unit (which also happens to be 35mm but is a different thing) is an etalon plus a pair of collimating lenses (just like your PST), so I didn't have to mess around with additional collimators. I just stuck it in the f/7 beam (it is designed for f/7 but can work fine with something longer if placed correctly). I already had the DSII unit, so it was a no brainer.

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Re: PST Etalon with a Quark, Log & Results

Post by Merlin66 »

The PST etalon assembly is designed to accept an f10 input beam and when positioned at the correct -200mm presents a collimated beam to the etalon.
One issue, which would impact on the performance would be the blocking filter bandwidth in the Quark.
I recently tested a PST blocker and it was close to 6A FWHM.
I don’t know what the Quark blocker FWHM is.


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Re: PST Etalon with a Quark, Log & Results

Post by george9 »

Won't the Quark etalon itself will serve as the blocking filter for the PST? That is, even if the Quark blocker were 20A (i.e., seemingly too wide), the etalon would block spikes for example 8A away from its centerline. Is the concern that the etalon has high shoulders and won't block enough of the off-band spikes?

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Re: PST Etalon with a Quark, Log & Results

Post by MapleRidge »

Hi George...

Interesting that you have a Quark after the DSII module, something I have been meaning to try to setup as a DS on my 150mm, F8 OTA + DSII. Which version of the quark are you using, and I'm curious how far behind the DSII does the Quark reach focus? I tested a friends Standard Chromosphere model with the built in telecentric and had to add a lot of extenders to reach focus on its own. I did not get a chance to try it as a DS on the modded scope before I had to return it.

I'd be interested to see some example images and setup pics/details if you can share?

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Re: PST Etalon with a Quark, Log & Results

Post by george9 »

Hi, Brian. I have a classic Quark chromosphere (i.e., not combo). As I said, pretty narrow at around .5-.6A. I don't image, but I can describe the visual. No more double limb. Prominences have varied brightnesses, some are same as the solar disk and some are dimmer, leading to a slight filaprom where it hits the surface. It looks a lot like a high-magnification processed image when seeing is great. And contrast looks almost similar to my LS80 DSII, which has great contrast.

I put the DSII (from LS80) just a centimeter or two back from where it should be just because the pressure tuner keeps me from inserting it too far up the 4" focuser. An LS100 DSII might go up further. But I don't see much of a difference between where it currently is and even a few centimeters further back, so it doesn't seem to matter much. Then I have a 2"-long Lunt spacer and a Feathertouch 2.5" draw tube focuser, then the Quark, then a 1.25" diagonal, then a binoviewer. And with all that, I still need to pull it back a little further, so I can either shove in an extra 2" extension or just pull the DSII about half a centimeter further back from the objective and that just makes it. And remember that a binoviewer takes up a lot of back focus.

Therefore, it doesn't surprise me that you need all the extensions. Sometimes I just throw on one or two diagonals to soak up extra space.

Let me look for an image of the setup.

George


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Re: PST Etalon with a Quark, Log & Results

Post by george9 »

Here is my setup. The main scope is a 155mm f/7. You see a 4" focuser, a Precise parts adapter, the DSII unit from an LS80, a spacer, an adapter to the Feathertouch, a 2" Feathertouch focuser with 2.5" draw tube (racked all the way out), the Quark chromosphere (with 4.2x), a Baader T2 prism, and a 32mm Plossl. You'll notice that the 4" focuser is racked out about a quarter inch. That obviates the need for me to add yet another spacer, but I would rather than it were all the way in for better theoretical placement of the DSII.

Next to that is a 130mm f/6.3 with a Lunt 2" Herschel wedge and my Denk II binoviewer with 21MM Denk eyepieces. And the third scope is a 70mm f/6.8 with a Lunt B1200 CaK filter and an R2 video camera. All on an AP1100 mount.
IMG_3073b.jpg
IMG_3073b.jpg (328.78 KiB) Viewed 9209 times
George


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Re: PST Etalon with a Quark, Log & Results

Post by Merlin66 »

George,
Fair comment.
It would depend how how “matched” the transmission curves are and how close they are in CWL.


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Re: PST Etalon with a Quark, Log & Results

Post by Bob Yoesle »

Very nice implementation George!
After the Quark, you are over f/30 and don't need the lenses.
RE: PST etalon. Remember, an air spaced etalon is a different beast than a solid spaced etalon, and suffers from the decreased refractive index of air compared to a solid spaced etalon, and field and instrument angles will not be as easily optimized when placed after the objective. It will work better in a collimated system versus a telecentric system. With say an f33 telecentric system (f8 refractor feeding the Quark), it will likely perform no better than if it were "naked" in about an f10-15 light cone, and therefore the bandpass and transmission curve would be considerably widened. This is probably why Marty can't get completely rid of the double limb, and why George can - George's air-spaced DSII etalon is located in the ideal collimated beam of the DSII, and the smaller Quark etalon following it is located in its telecentric system which is better suited for small solid spaced etalons.

So Marty should indeed try the collimating and refocusing lenses with the PST etalon, then follow with the Quark - which indeed will act as both a blocking filter and etalon for double stacking the PST etalon - and see what happens...


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Re: PST Etalon with a Quark, Log & Results

Post by MalVeauX »

Interesting!

Can anyone speak to the placement of the PST etalon (with collimating lenses) with an F10 SCT? Will it need to have extensions or how does one measure things out there? I know they're used with SCT's commonly, but I'm not sure how the focus system is handled, compared to the refractor system with the -200mm and all that for the PST etalon. I will be switching to SCT in February or so, and if that means putting the PST etalon (with its lenses) first, and then the Quark, and if that kills the double limb, I'd be happy with that for the time being until I can figure out something better that is affordable.

I was looking at this:

viewtopic.php?t=24283

Looks doable. Can't quite tell what every part there is. But I assume the PST etalon can be put right into the visual back, the primary mirror can move to allow focus there, and the Quark would slide in after that, has the blocking filter built in, and set? Though I'm curious if I would still need potentially a blacking filter after the PST etalon to ensure the same issue like now isn't happening?

I assume this is a simple answer question, but, if it's simple to put a PST etalon behind a F10 SCT, where is the complication with respect to double stacking with two PST etalons?

Thanks!

Very best,


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Re: PST Etalon with a Quark, Log & Results

Post by MalVeauX »

Thanks Bob,

Good point, affordability is definitely relative.

I would love to just get two Quantums at 0.6A or 0.7A and call it a lifetime, but, that isn't happening... ever, unless someone wills them to me or I find an amazing estate auction that no one else made it to. So might as well explore other options.

So, from my perspective, affordability going from something like a Quark and/or PST setup, or a combination of either of them, would be to look at some of the Lunt options. I've seen how Harald has his unigraph setup with a Lunt DS module and a basic Lunt 35mm etalon in his big folded refractor and there's no double limb there. And those two Lunt etalons are cheaper than a single new tight Quantum (which won't even eliminate a double limb on its own even at 0.3A). I would consider a $4k investment in something like that to be affordable considering what it can do.

Unaffordable for me would be a new Quantum or similar.

Following all of Christian's documentation, I'd love enjoy having a good 0.5~0.6A etalon and have a second filter that is around 1A to shave the skirt, but finding that with high transmission is no simple task, also not inexpensive, but way more affordable than two Quantums or similar combinations.

So that leads back to maybe something like the Lunt etalons and/or combination of a Lunt etalon followed by either a PST or Quark, but ultimately I would think long term it would just make more sense to eventually have two Lunt etalons configured and a big blocking filter.

Until then though, still tinkering with the entry stuff since I already have them.

I can support a 4m to 8m effective focal length in Florida. Before the storm season, I routinely image at 4200mm with good seeing.

Currently looking to setup it up so that the C8 + Quark (with or without the PST etalon depending on how things turn out) with a 0.5x focal reducer with the ASI174MM will have me right back at 4200mm where I'm already imaging often.

And I mainly only want the double stack effects for the limb, for ARs and spots, I'm fine with just the Quark (at least this Quark that is).

Very best,


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Re: PST Etalon with a Quark, Log & Results

Post by Merlin66 »

I occasionally have the PST etalon assembly double stacked on the SM60/ED80 (which gives an f10 beam) and BF15..
The image below was taken on 31 Dec 2018 using an ES x3 extender (for the first time) and the ASI 174 (excuse the NR - forgot to add the T2 tilter!)
I'd like to think that this combo effectively suppresses the Photospheric edge....
Sm60/Pst DS
Sm60/Pst DS
053.jpg (131.53 KiB) Viewed 9158 times


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Re: PST Etalon with a Quark, Log & Results

Post by MalVeauX »

Hrm,

It seems the limb is still present there too. It's not as stark, but you can see the transition as it's mostly without spicules and texture and has a blur to it. I have similar on my double limb. The super obvious double limb line goes away, but you can still see some kind of continuum leaking through. Interesting.

Thanks for the example!

Very best,


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Re: PST Etalon with a Quark, Log & Results

Post by Merlin66 »

Marty,
Yeah, you're probably correct....better seeing and better focus might show it more clearly....
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Re: PST Etalon with a Quark, Log & Results

Post by MapleRidge »

Hi George...

Thanks for posting the image of the DS system and the description of the spacing and fittings. The basic setup of the OTA/DSII is pretty much the same as I have with the Celestron OTA and DSII module. Spacing of a Quark should work, though more spacers likely will be needed since I don't use a binoviewer.

Brian


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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
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iOptron CEM70G Mount carrying:
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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
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