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Re: PST Etalon with a Quark, Log & Results

Posted: Tue Jan 01, 2019 6:50 pm
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 9268 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 9266 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 9260 times
Double stack (Quark + PST etalon):
Test_Limb_DS.jpg
Test_Limb_DS.jpg (12.04 KiB) Viewed 9260 times
Very best,

Re: PST Etalon with a Quark, Log & Results

Posted: Tue Jan 01, 2019 8:59 pm
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,

Re: PST Etalon with a Quark, Log & Results

Posted: Tue Jan 01, 2019 9:07 pm
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.

Re: PST Etalon with a Quark, Log & Results

Posted: Tue Jan 01, 2019 9:36 pm
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.

Very best,

Re: PST Etalon with a Quark, Log & Results

Posted: Tue Jan 01, 2019 11:18 pm
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....

Re: PST Etalon with a Quark, Log & Results

Posted: Tue Jan 01, 2019 11:42 pm
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,

Re: PST Etalon with a Quark, Log & Results

Posted: Tue Jan 01, 2019 11:49 pm
by Merlin66
Marty,
Yeah, that looks good for a PST.....

Re: PST Etalon with a Quark, Log & Results

Posted: Wed Jan 02, 2019 12:01 am
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.

Very best,

Re: PST Etalon with a Quark, Log & Results

Posted: Wed Jan 02, 2019 12:03 am
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.

George

Re: PST Etalon with a Quark, Log & Results

Posted: Wed Jan 02, 2019 12:06 am
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)

Re: PST Etalon with a Quark, Log & Results

Posted: Wed Jan 02, 2019 12:15 am
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,

Re: PST Etalon with a Quark, Log & Results

Posted: Wed Jan 02, 2019 12:31 am
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.

George

Re: PST Etalon with a Quark, Log & Results

Posted: Wed Jan 02, 2019 12:40 am
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.

Re: PST Etalon with a Quark, Log & Results

Posted: Wed Jan 02, 2019 1:31 am
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?

George

Re: PST Etalon with a Quark, Log & Results

Posted: Wed Jan 02, 2019 1:58 am
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?

Thanks,
Brian

Re: PST Etalon with a Quark, Log & Results

Posted: Wed Jan 02, 2019 2:46 am
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

Re: PST Etalon with a Quark, Log & Results

Posted: Wed Jan 02, 2019 2:58 am
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 9237 times
George

Re: PST Etalon with a Quark, Log & Results

Posted: Wed Jan 02, 2019 4:47 am
by Merlin66
George,
Fair comment.
It would depend how how “matched” the transmission curves are and how close they are in CWL.

Re: PST Etalon with a Quark, Log & Results

Posted: Wed Jan 02, 2019 3:44 pm
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...

Re: PST Etalon with a Quark, Log & Results

Posted: Wed Jan 02, 2019 5:49 pm
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,

Re: PST Etalon with a Quark, Log & Results

Posted: Wed Jan 02, 2019 8:03 pm
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,

Re: PST Etalon with a Quark, Log & Results

Posted: Wed Jan 02, 2019 9:23 pm
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 9186 times

Re: PST Etalon with a Quark, Log & Results

Posted: Wed Jan 02, 2019 9:43 pm
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,

Re: PST Etalon with a Quark, Log & Results

Posted: Wed Jan 02, 2019 9:51 pm
by Merlin66
Marty,
Yeah, you're probably correct....better seeing and better focus might show it more clearly....
Onwards and Upwards.

Re: PST Etalon with a Quark, Log & Results

Posted: Wed Jan 02, 2019 11:31 pm
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

Re: PST Etalon with a Quark, Log & Results

Posted: Thu Jan 03, 2019 5:50 am
by Merlin66
Marty,
Another factor would be the amount of off band; the further from the Ha CWL the more likely the chance to pick up the Continuum......

Re: PST Etalon with a Quark, Log & Results

Posted: Thu Jan 03, 2019 10:23 am
by marktownley
Looking at the unstretched pictures taken with the Quark, and then Quark + PST, both are wide bandpass. Be interesting to see what a 'raw' unstretched / no contrast full disk looks like with your PST. Personally I think you have 2 'wide' etalons. Here's a shot with my Quark double stacked with a naked PST etalon on my ED80 from 2017.

Imageha-active-regions-q80-colour by Mark Townley, on Flickr

Re: PST Etalon with a Quark, Log & Results

Posted: Thu Jan 03, 2019 1:16 pm
by MalVeauX
Good point about being on band. I'm probably off-band a little. I usually try to push towards the blue side as it seems to have more contrast on the surface. But that was the Quark by itself. If I ever get a clear day, I will try to tune the Quark and the PST and try to document it with different examples at the limb. That could very well be the problem! I figured if my filaments were dark, it was on band, but maybe it's not?

Very best,

Re: PST Etalon with a Quark, Log & Results

Posted: Thu Jan 03, 2019 2:02 pm
by Bob Yoesle
Looks like you nailed it Mark! Your greyscale is perfect:

https://www.flickr.com/photos/brierleyh ... otostream/

Re: PST Etalon with a Quark, Log & Results

Posted: Tue Jan 08, 2019 5:43 pm
by MalVeauX
Heya,

I managed to test a little bit today. I tried tuning the Quark differently to see if I could match the PST. I usually tune the Quark to 9 o'clock as I find it has more contrast there. Tuning the Quark at 12 o'clock was my first round of testing, but then clouds came in. I think it helped a little? Didn't solve the issue with the double limb, but I think it improved it. So maybe I'm just not tuned to match on each etalon quite yet?

I also noticed in some places I could see the double limb, and in others, it seemed to be supressed. Maybe some kind of sweet spot? Or an issue with tilt or being on/off band? Not uniform?

Image

Image

Image

Image

Image

Very best,

Re: PST Etalon with a Quark, Log & Results

Posted: Tue Jan 08, 2019 7:28 pm
by marktownley
I think this is an improvement Marty, that first image is a cracker!

Re: PST Etalon with a Quark, Log & Results

Posted: Tue Jan 08, 2019 11:27 pm
by Bob Yoesle
These are a major improvement Marty! Very much closer to being on band I would say.

Re: PST Etalon with a Quark, Log & Results

Posted: Wed Jan 09, 2019 7:29 pm
by MalVeauX
Some more testing today.

I left the Quark at 12 o'clock and then just tuned the PST a little back and forth to see what would happen. It would basically go from a featureless grey smear to a starkly over-exposed white. So between the two I just went for the most uniform across the FOV with contrast. Tested it on the limb and on the current AR to compare to yesterday's. Still a hint of the double limb present I think.

Image

Image

Image

Image

Very best,

Re: PST Etalon with a Quark, Log & Results

Posted: Wed Jan 09, 2019 8:35 pm
by marktownley
You're getting there Marty. Like I mentioned, I think both of your etalons have a wide passband. You're doing a lot of stretching / contrast etc in your post processing which I think also enhances the ghost of the double limb.

When I double stack in the quark and PST my tuning process is to tune the PST etalon to get uniform illumination, then to tune the quark to get onband.

Re: PST Etalon with a Quark, Log & Results

Posted: Wed Jan 09, 2019 9:11 pm
by MalVeauX
Thanks Mark, that's a good point about starting with the PST and then the Quark for tuning. I'll try that next session.

Very best,

Re: PST Etalon with a Quark, Log & Results

Posted: Thu Jan 10, 2019 2:58 am
by Valery
MalVeauX wrote: Wed Jan 09, 2019 9:11 pm Thanks Mark, that's a good point about starting with the PST and then the Quark for tuning. I'll try that next session.

Very best,
Due to a small size of a PST sweet spot, this will probably work only for a very narrow FOV.

Valery

Re: PST Etalon with a Quark, Log & Results

Posted: Thu Jan 10, 2019 6:37 am
by marktownley
Valery wrote: Thu Jan 10, 2019 2:58 am
MalVeauX wrote: Wed Jan 09, 2019 9:11 pm Thanks Mark, that's a good point about starting with the PST and then the Quark for tuning. I'll try that next session.

Very best,
Due to a small size of a PST sweet spot, this will probably work only for a very narrow FOV.

Valery
The PST etalon is in a telecentric beam so i'm not seeing a sweet spot Valery in my setup (f43 or f32)- sweet spot is only in a collimated light beam.

Re: PST Etalon with a Quark, Log & Results

Posted: Thu Jan 10, 2019 2:38 pm
by Valery
marktownley wrote: Thu Jan 10, 2019 6:37 am
The PST etalon is in a telecentric beam so i'm not seeing a sweet spot Valery in my setup (f43 or f32)- sweet spot is only in a collimated light beam.
Hah! I thinked that you adviced to use a PST etalon in it's native F/10 - collimation - refocusing mode and then use a Quark with it's telecentric! My mistake.

Re: PST Etalon with a Quark, Log & Results

Posted: Sat Jan 12, 2019 7:19 pm
by MalVeauX
Heya,

Had a chance to try and test tuning again. I tuned the Quark far blue and far red to see which direction was the closest to match the PST etalon. The red shift was the worst of the two directions. The blue shift, all the way, where my Quark is normally sitting, was off a bit too. But I found around 10~11 o'clock on the Quark and a little gentle sweeping through the pressure range on the PST etalon allowed me to get a little closer to being on band. Still not quite there. But maybe a little closer than before? I started marking on the components where to align them so I know where to start next time and will keep testing and tweaking what can be done with this.

Image

Image

Image

Image
Quark_PSTEtalon_Tuned.jpg
Quark_PSTEtalon_Tuned.jpg (116.43 KiB) Viewed 8657 times
Very best,

Re: PST Etalon with a Quark, Log & Results

Posted: Sun Jan 13, 2019 11:14 am
by marktownley
They're all good but I do like number 4. Any chance you could put an unprocessed (straight from stack) version of this image? I'm curious as to what your raw data looks like before processing.

Re: PST Etalon with a Quark, Log & Results

Posted: Sun Jan 13, 2019 1:19 pm
by MalVeauX
marktownley wrote: Sun Jan 13, 2019 11:14 am They're all good but I do like number 4. Any chance you could put an unprocessed (straight from stack) version of this image? I'm curious as to what your raw data looks like before processing.
Sure thing,

Here's the Quark on it's own and the Quark + PST Etalon, no processing, just raw output from 100 frames stacked.

Quark (single):
Exposed to fill histogram to try to get as much into one shot as possible to test processing.
Quark_SS_Limb_01.jpg
Quark_SS_Limb_01.jpg (82.74 KiB) Viewed 8628 times
Quark + PST Etalon (double):
Exposed to fill histogram without clipping to again get as much into one shot as possible to test processing.
Quark_PST_DS_01.jpg
Quark_PST_DS_01.jpg (119.25 KiB) Viewed 8628 times
Very best,

Re: PST Etalon with a Quark, Log & Results

Posted: Sun Jan 13, 2019 8:48 pm
by george9
Very nice improvement. There was a bump of a prom with a filaprom to a subtle AR below it today (much like what I see above), but if these were taken yesterday, it would have moved by now. Amazing what the processing brings out (earlier post).

George

Re: PST Etalon with a Quark, Log & Results

Posted: Sun Jan 13, 2019 10:21 pm
by MalVeauX
Heya,

I tried some more tuning options and processing options and I'm happier with the results today on the limb. Even though the double limb is not 100% eliminated, it makes processing it out a lot easier and more natural looking to me at least. Here's today's results under really excellent seeing (the limb was a treat to just watch despite no major features):

Image

Image

Image

Image

Image

Image

Image

Mosaic made with an ST80 masked to 60mm with the same imaging train. 4 images stitched together.

Image
SolarSetup_ST80_01132019.jpg
SolarSetup_ST80_01132019.jpg (91.03 KiB) Viewed 8598 times
Very best,

Re: PST Etalon with a Quark, Log & Results

Posted: Sun Jan 13, 2019 10:33 pm
by marktownley
Spot on Marty!

Re: PST Etalon with a Quark, Log & Results

Posted: Sun Jan 13, 2019 10:44 pm
by MapleRidge
Hi Marty...

These images are really sharp and the limb details show so much detail despite being such small proms. Your setup is working very nicely :bow

Brian

Re: PST Etalon with a Quark, Log & Results

Posted: Sat Jan 19, 2019 7:27 pm
by Bob Yoesle
Hi Marty,

Upon reflection and going back to some references, I believe there could be a couple of things going on with your images. The recent images are better with regard to the double limb, but it is still subtly revealing itself. According to Bray & Loughhead in The Solar Chromosphere (1974, page 19):

A second consequence of tuning the filter progressively further into the wings of the line is the eventual re-appearance of the photospheric limb, even in the absence of of parasitic light. ... high-resolution observations show that the photospheric limb first begins to re-appear at Ha +/- 0.65 A... As one moves further out from the centre line, the photospheric limb rapidly becomes more prominent and appears as a sharp regular boundary crossed at irregular intervals by isolated chromospheric features (Plate 2.8)... If the bandwidth of the filter is sufficiently broad it follows [from the foregoing] that the photospheric limb will be present, regardless of the wavelength setting of the filter.

Plate 2.8 SM.jpg
Plate 2.8 SM.jpg (57.81 KiB) Viewed 8422 times

From your images, the presence of the double limb can represent that the filter system bandpass is perhaps a bit too wide to completely eliminate parasitic continuum from the photosphere. However, it seems to be more likely that you simply are tuned a little too far off the H alpha line. I have noted many of your images look somewhat "peculiar." I thought this might be due to excessive processing as noted by Mark. I believe the plates below demonstrate you may indeed be +/- 0.5 A or more off-band with most of your images, which seem to show the "dark mottles" that are more prominent off-band, but which are largely absent when on-band:

Plate 2.5 SM.jpg
Plate 2.5 SM.jpg (65.48 KiB) Viewed 8422 times
Plate 2.6 SM.jpg
Plate 2.6 SM.jpg (66.66 KiB) Viewed 8422 times
Plate 3.1 SM.jpg
Plate 3.1 SM.jpg (72.96 KiB) Viewed 8422 times
Plate 3.4 SM.jpg
Plate 3.4 SM.jpg (75.13 KiB) Viewed 8422 times

The predominance of the dark "spiky" mottles in your (positive) images appear to reveal you are perhaps +/- 0.5 A off-band as seen in Plate 2.6 and 3.4, and the double limb might indicate you have some additional leaking continuum from filter band-pass issues (e.g. transmission profile "wings"). On the other hand, you might be tuned closer to +/- 0.65 A, and the double limb would be present no matter what the filter system bandpass is.

The only way to tell if you have a band-pass issue (continuum leakage) is to get tuned on-band, and if you are not seeing a double limb, then you have very good double stacked filter performance, and going off-band and seeing the double limb is normal.

Re: PST Etalon with a Quark, Log & Results

Posted: Sat Jan 19, 2019 7:51 pm
by marktownley
MalVeauX wrote: Sun Jan 13, 2019 1:19 pm
marktownley wrote: Sun Jan 13, 2019 11:14 am They're all good but I do like number 4. Any chance you could put an unprocessed (straight from stack) version of this image? I'm curious as to what your raw data looks like before processing.
Sure thing,

Here's the Quark on it's own and the Quark + PST Etalon, no processing, just raw output from 100 frames stacked.

Quark (single):
Exposed to fill histogram to try to get as much into one shot as possible to test processing.

Quark_SS_Limb_01.jpg

Quark + PST Etalon (double):
Exposed to fill histogram without clipping to again get as much into one shot as possible to test processing.

Quark_PST_DS_01.jpg

Very best,

Try your stacking with 'cropped ' selected on AS3 Marty 👍

Re: PST Etalon with a Quark, Log & Results

Posted: Sat Jan 19, 2019 11:27 pm
by MalVeauX
Thanks all,

Will test more as soon as these storms pass!

Very best,

Re: PST Etalon with a Quark, Log & Results

Posted: Sat Jan 19, 2019 11:38 pm
by Merlin66
Marty,
I've started to play "seriously" with imppg to hopefully improve my processing skills.
One thing I do notice is that depending on the processing I can "pull" the double edge out of almost any image....
As per my previous early comments I think CWL on Ha is a clear winner to reduce the double edge but it may also be aggravated by your processing techniques?
Just trying to help.....

Re: PST Etalon with a Quark, Log & Results

Posted: Sat Jan 19, 2019 11:48 pm
by Merlin66
Here's the above DS jpg file in a quick (not perfect!!) run through ImPPG.
Marty_Quark_PST_DS_01_imppg.jpg
Marty_Quark_PST_DS_01_imppg.jpg (141.73 KiB) Viewed 8397 times