25 replies to this topic

[SchoolMaster]

Pause-Swap-Resume is title coined by MarMax to describe an EAA technique that borrows from AP principles.

We make no claims to have invented this. If you have been doing this for years, share your experience.

AP practitioners often use filter sets, SHO or LRGB to capture and emphasize aspects of their work, although they must use post-processing to fit the parts together.

PSR is an EAA technique intended to use the capabilities of SharpCap ( and Jocular or other software I'm less familiar with, maybe) to achieve emphasis or de-emphasis of EAA target elements.

I hope this topic will be come an area to discuss this technique and show examples of what is possible.

Since we're live stacking and live combining the two images, it's a valid EAA process, similar to stretch, but different.

Here's three captures to show the basic ideas.

Edited by SchoolMaster, 29 May 2023 - 10:48 AM.

[SchoolMaster]

M16
Gain 300, 300 secs - 10 sec subs



This is a conventional EAA capture of M16, stretched to bring out the nebulosity but it also results in a lot of stars being prominent.

Edited by SchoolMaster, 29 May 2023 - 06:38 AM.

[SchoolMaster]

M16
Gain 300, 300 secs - 30 sec subs.



Same kit and target, but with a 7nm Ha filter added, stretched to emphasize the nebula. The stars are much less prominent.

[SchoolMaster]

PSR capture
M16
Gain 300
120 secs - 30 sec subs 7nm Ha
180 secs - 10 sec subs no filter



In this PSR capture, 120 secs was captured and stacked with the 7nm Ha filter, the capture was Paused, the filter was Swapped out, the system was re-focused (EAF makes this VERY simple), and new flats were loaded, and the capture was Resumed.

This was my first attempt at this and there are a lot of minor tweaks to improve the process and better balance the two components of the image, handle the different brightness of the two halves of the capture and so on.

I'm using a ZWO533MM Pro cooled to 0C. It's a very clean camera, so no darks, only hot pixel removal.
The AT125EDL has a big image circle and a clean optical train, so I could do without flats to start with.

To prepare, I might need to make darks for the camera (I'm not), make flats for each OTA/Filter combination, get EAF focus and image scale information for each filter combination.

In the example above, I did the Ha first and added the luminance. To get the best results, I think it would be better to start with the luminance and add the Ha. If the image needs to be adjusted, it is fairly simple to capture a little more HA.

The capture length is set to 31 minutes in Sharpcap because I'm going to be controlling things manually, saving raws, and work-in progress, as needed.

There is nothing to prevent using more than one filter, say Ha and OII, or leaving out the luminance and capturing with two or three different filters, M1 would be an interesting target.

There is nothing, in principle, that would prevent this technique being used with an OSC to emphasize various nebulosity elements on top of an existing capture.

Edited by SchoolMaster, 29 May 2023 - 06:40 AM.

[alphatripleplus]

Starlight Live EAA software (which only works with Starlight Xpress cameras) has the same ability to pause a livestack, change filters, and resume the live stack. However, it also allows the user to assign each filtered view into one or more different colour channels, for the purpose of creating a colour image  in real time using a mono camera and filters; Jocular can also do the same.

 

Unless SharpCap allows the user to assign filtered views to specific colour channel,  I don't believe SharpCap allows the creation of a colour image with a mono camera in real time. If SharpCap had the abliity to create a colour image using the PSR technique with filters and a mono camera, I would find the technique of greater interest. Just my 2 cents.

[SchoolMaster]

Starlight Live EAA software (which only works with Starlight Xpress cameras) has the same ability to pause a livestack, change filters, and resume the live stack. However, it also allows the user to assign each filtered view into one or more different colour channels, for the purpose of creating a colour image  in real time using a mono camera and filters; Jocular can also do the same.
 
Unless SharpCap allows the user to assign filtered views to specific colour channel,  I don't believe SharpCap allows the creation of a colour image with a mono camera in real time. If SharpCap had the abliity to create a colour image using the PSR technique with filters and a mono camera, I would find the technique of greater interest. Just my 2 cents.

ABSOLUTELY! I've wanted to be able to set a false color to mono captures from the beginning.

I still think that there's a lot that can be done now with mono to bring out details.

[alphatripleplus]

Yes, I should add that I think the Pause Swap Resume technique might be interesting to try, as you have noted in your example. However,  it would probably gain a lot more attention if SharpCap enabled users to access colour channels as I noted in my previous post. 

[steveincolo]

Starlight Live EAA software (which only works with Starlight Xpress cameras) has the same ability to pause a livestack, change filters, and resume the live stack. However, it also allows the user to assign each filtered view into one or more different colour channels, for the purpose of creating a colour image  in real time using a mono camera and filters; Jocular can also do the same.

 

Unless SharpCap allows the user to assign filtered views to specific colour channel,  I don't believe SharpCap allows the creation of a colour image with a mono camera in real time. If SharpCap had the abliity to create a colour image using the PSR technique with filters and a mono camera, I would find the technique of greater interest. Just my 2 cents.

I recently found out that AstroToaster now has the ability to assign filters to color channels.  I’ve only tested it with saved subs so far. 

Edited by steveincolo, 29 May 2023 - 08:32 AM.

[SchoolMaster]

Yes, I should add that I think the Pause Swap Resume technique might be interesting to try, as you have noted in your example. However,  it would probably gain a lot more attention if SharpCap enabled users to access colour channels as I noted in my previous post.

With that capability. it would make a huge difference to EAA. Mono is so much faster. Even is the simplest cases it would allow for 'natural' color for mono narrowband.

Anyone who knows the great man well should have a quiet word with him. However, I can see that this is a very 'fringe' kind of thing, not for newbies, not for APers, not for OSC users, so just you me and a few of our closest friends.

[SchoolMaster]

I recently found out that AstroToaster now has the ability to assign filters to color channels.  I’ve only tested it with saved subs so far.

Does that work with mono captures?

[steveincolo]

Does that work with mono captures?

Absolutely!  AstroToaster is interesting.  It uses DeepSkyStacker to align and stack, which (IMO) is a bit more advanced than either SharpCap or Jocular.  On the other hand, the adjustment tools aren't quite as good as either of those other two.

 

A nice feature of AstroToaster is the ability to eliminate or include subs and restack.  Jocular can do this as well.

[steveincolo]

With that capability. it would make a huge difference to EAA. Mono is so much faster. Even is the simplest cases it would allow for 'natural' color for mono narrowband.

Anyone who knows the great man well should have a quiet word with him. However, I can see that this is a very 'fringe' kind of thing, not for newbies, not for APers, not for OSC users, so just you me and a few of our closest friends.

I suspect adding this capability to SharpCap would be a much bigger task than any of the recent enhancements to live stacking.  That said, luminance sharpening might be a first step!

 

It's for APers, too, they get to have a nice live view of their DSO before they turn in to bed and let their scope run for the rest of the night.  I think that's why the NINA/PixInsight live stacking plugin exists.

Edited by steveincolo, 29 May 2023 - 10:41 AM.

[SchoolMaster]

I suspect adding this capability to SharpCap would be a much bigger task than any of the recent enhancements to live stacking.  That said, luminance sharpening might be a first step!

A simple RGB setting to replace the value for mono should be fairly easy, I would expect.

[steveincolo]

A simple RGB setting to replace the value for mono should be fairly easy, I would expect.

Easy for us to say! 

[SchoolMaster]

Easy for us to say! 

I was an owner and executive in a software company for 20 years. We worked, amongst other things, on the application software for the launch of the original Mac in 1984.

[steveincolo]

I was an owner and executive in a software company for 20 years. We worked, amongst other things, on the application software for the launch of the original Mac in 1984.

I worked in software for ten years myself.   To do mono + filters right is not easy!  And it's a different paradigm:  it could require entirely rewriting the underlying objects in the code.  

 

It was easier for AstroToaster because it uses a stacking and alignment engine that already had the capability.  And Jocular was designed from pretty early on for the capability.  

[MarMax]

Excellent topic SchoolMaster and thank you for the PSR credit. I also agree this is a fringe activity and may not generate enough interest to be on the radar for Dr. Robin Glover. This topic will be a good way to test the water and see how PSR works. And I've been most interested in trying it with OSC versus mono.

 

Your test images are looking good and I'd like to do some PSR testing of my own but the clouds have been relentless in Southern California. I've got quite the backlog and a lot of things to test and image before jumping back into PSR. 

 

Something I can do is post up a question on the SharpCap Forum and ask about techniques for doing pause-swap-resume with SharpCap 4.1 beta and see what the good Doctor says.

[SchoolMaster]

Excellent topic SchoolMaster and thank you for the PSR credit. I also agree this is a fringe activity and may not generate enough interest to be on the radar for Dr. Robin Glover. This topic will be a good way to test the water and see how PSR works. And I've been most interested in trying it with OSC versus mono.
 
Your test images are looking good and I'd like to do some PSR testing of my own but the clouds have been relentless in Southern California. I've got quite the backlog and a lot of things to test and image before jumping back into PSR. 
 
Something I can do is post up a question on the SharpCap Forum and ask about techniques for doing pause-swap-resume with SharpCap 4.1 beta and see what the good Doctor says.

I also like the idea of 'thickening up' nebulae with Ha, using an OSC. 57Cyg area is available in the mornings and I have the FMA180/294MC mounted up.

[Tfer]

I find the idea of this intriguing enough, to order a filter drawer…

I’d use my 294MC with a UV/IR, then swap it out for my Celestron UHC/LPR.

[SchoolMaster]

I find the idea of this intriguing enough, to order a filter drawer…

I’d use my 294MC with a UV/IR, then swap it out for my Celestron UHC/LPR.

Great

 

Post up any results, when winter approaches and it gets dark, of course,

[Tfer]

Great

Post up any results, when winter approaches and it gets dark, of course,

The advantage of time!

[MarMax]

Speaking of technique, it would be nice to keep track of the basics for each camera/filter combination. I've wondered about the order of filters and stack time per filter. My first attempts were not successful but I did start with narrowband and finish with luminance (UV/IR cut). It would be helpful to know if a specific order is best.

 

With SharpCap the images should stack post-swap provided the histograms are equivalent (to be determined ahead of time). But is the best order NB > Luminance or Luminance > NB? And at what ratio should we run NB/Luminance?

 

If we keep track of some basic parameters to share with posted images that will help find the best workflow. Since there is no ability to go back or delete subs, this is like a "one take" studio recording. Experimentation on a small scale is best so finding a minimum total stack time that allows qualitative review is ideal.

 

Suggestions on a good starting point would be nice. In Bortle 8ish and 2.5/5 conditions, I'm usually running a minimum of 5-10 minutes with Luminance and 20-30 minutes with NB (talking non-Hyperstar here). And for the most part I'm just running my mouth since any decent EAA time looks to be about two weeks out.

[MarMax]

This topic has been quiet for a while now and I've been considering purchasing an OIII filter. Mainly to delve further into PSR with SharpCap. I'd like to have, for OSC and using Ha and OIII narrowband filters, correct order and integration suggestions.

 

The plan would be to pick up the Antlia EDGE 4.5nm OIII filter to match the EDGE 4.5mn Ha filter that I already have. I'm only guessing at a 90/10 or 95/5 ration for OIII. So this is 54-57 minutes of OIII to 3-6 minutes of Ha for a 60 minute stack. Does this seem like a good start?

 

And the sequence can only be Ha>OIII or OIII>Ha . . . so is there a "best" order or do I need to try both and see?

[bigbangbaby]

Mike, the portion of time you spend on each filter depends on the target. The Squid, for example, is predominantly OIII, while the surrounding Flying Bat is an Ha region. If the target of interest has an OIII component and is well placed before moon rise, shoot OIII first because, as you know, moonlight degrades OIII images. Ha seems insensitive to it. Keep in mind, every filter change necessitates a refocus. I've had mixed success using focuser offsets and refocus each time for consistent results. I believe missed steps of the stepper motor is a possible reason the focuser doesn't repeat position.

[mgCatskills]

Mike, the portion of time you spend on each filter depends on the target. The Squid, for example, is predominantly OIII, while the surrounding Flying Bat is an Ha region. If the target of interest has an OIII component and is well placed before moon rise, shoot OIII first because, as you know, moonlight degrades OIII images. Ha seems insensitive to it. Keep in mind, every filter change necessitates a refocus. I've had mixed success using focuser offsets and refocus each time for consistent results. I believe missed steps of the stepper motor is a possible reason the focuser doesn't repeat position.

I wish I'd read this BEFORE I logged an hour on a heavily moonlit night trying to see the Squid last week.

Edited by mgCatskills, 28 October 2023 - 03:24 PM.