Jocular: a tool for astronomical observing with a camera

[Steve in Boulder]

On 18/04/2022 at 09:32, Martin Meredith said:

Apropos of the luminosity/chromaticity distinction, I spotted in Bracken's Deep Sky Imaging Primer a mention of adding synthetic luminance (formed from a weighted sum of RGB) to the actual luminance, to decrease luminance noise even further. I ought to do this (I currently use synL when there is no real L). It sounds like using the same info twice but I guess it is ok.

For the EEA context, to avoid going down the slope towards AP, I think it is necessary to do quite a bit of chromaticity manipulation automatically. For instance, colour gradients are (optionally) subtracted from each channel, but there is no option to control the degree of subtraction as there is with the luminosity control. Similarly I only provide a single colour stretch family (corrected gamma) rather than the various options available for luminosity.

Still, I sometimes feel that there is room for more chromaticity control... I removed the blue-yellow and green-magenta oppositions that corrected the background as they didn't seem necessary -- the automated gradient removal seems to do the trick. Its all a bit lonely for chromaticity at present with just colour stretch and saturation 🙂 

BTW I've started work on automatic detection of G2V stars and now need to compute the colour ratio corrections robustly. One difficulty is not having a good record (in all cases) of the altitude of the detected G2V star, which is necessary to build a decent map in order to allow G2V correction in cases where there is no G2V in the image (the majority of cases are like this). 

 

One possible enhancement for chromaticity would be noise reduction/smoothing.  Or just move the color binning control to the main view. 

[Martin Meredith]

Chromaticity already has a slight degree of 'timid' noise reduction in that the colour stretch is the corrected gamma whose low-intensity end is noise-reduced. Perhaps a slightly more vigorous form of NR is required for these channels.

I recently expanded the range of binning options for chromaticity (was 1x1 and 2x2, now 3x3 and 4x4 are included, though for my pixels at least they tend to produce smearing artefacts). It might be worth trying out fractional colour binning and adding that control to the interface.

Colour processing in an EEVA context (i.e. trying to minimise the amount of user-controlled processing) is a fascinating business. It turns out that the critical step is boosting the colour channels (so they can be appropriately integrated with the L) while preserving colour ratios.

[AKB]

On 16/04/2022 at 15:36, Martin Meredith said:

I've just uploaded a new version (0.5.6) to the Python package repository.

Just noticed this!

Small problem... the slider control for sharpen appears to be missing:

Running on Apple Mac.

Tony

[Steve in Boulder]

3 hours ago, AKB said:

Just noticed this!

Small problem... the slider control for sharpen appears to be missing:

Running on Apple Mac.

Tony

Happened to me too when I upgraded to 0.5.6. Per Martin, the problem is a stored value for sharpening for a previous version.  Edit ‘gui_settings.json’, change the value of ‘unsharp_amount’ to 0.  Worked for me. 

[AKB]

19 hours ago, Steve in Boulder said:

Edit ‘gui_settings.json’, change the value of ‘unsharp_amount’ to 0.  Worked for me.

Worked for me too!  Thanks.

[RobertI]

With the arrival of a new laptop I finally managed to install Jocular! Simply Googled "how to install Jocular" and I was taken to the downloads website, followed the clear and comprehensive instructions and worked first time. The guide is also excellent. I've been having fun playing with the test images and also uploaded my own FITS from a session in 2019 - see screenshot below.

I'm loving the controls, really well setup for EAA and fun to use. Being able to see each sub as it stacks and then step through each sub after is really useful, gives a much better understanding of what's going on. But it's also great if you just want to get the best view straight away with minimal fuss - it does it all for you. Will try to get plate solving working soon.

Unfortunately it would not connect to my Lodestar - I even tried installing USBlib as described in previous thread, but no joy. But it works fine with Starlight Live capturing into the watch folder.

Really looking forward to giving this a go for real when the nights get darker. Well done and thankyou to @Martin Meredith!  

 

[Mike JW]

Hi Rob,

I shall look forward to your adventures with Jocular. As you know J. does it all for me.

Mike

[RobertI]

Given the cloudy nights at the moment (frustrating given the sunny days) I thought I'd get the filter wheel set up to try some L+Ha or LRGB next time out using Jocular. I have a Xagyl filter wheel with an ASCOM driver which I control with a separate utility (I couldn't get jocular to connect to the filterwheel directly) and use StarlightLive for capture.

What is the best way of getting Jocular to recognise the different filtered subs to get a colour image with this setup?

I tried various approaches (including setting the RGB in SLL) but nothing seemed to result in colour images in jocular. The most logical approach seemed to be to set filterwheel to 'single' in the equipment section of Jocular and then tell Jocular what filter I was about to capture with, eg: 

• Select 'L' filter in jocular, move actual filter wheel to L filter, start watching in Jocular, start capturing in SLL (then stop in jocular & SLL after X exposures)
• Select 'R' filter in jocular, move actual filter wheel to R filter, start watching in Jocular, start capturing in SLL (then stop in jocular & SLL after X exposures)
• Select 'G' filter in jocular, etc.....

However this didn't seem to produce a colour image in Jocular, although I was looking at a red brick wall in the dark, so not sure what to expect!

Am I using Jocular in the right way for LRGB or have I missed the mark completely??

 

Edited July 24, 2022 by RobertI

[Steve in Boulder]

Assuming you activated LRGB by selecting it on the lower right, Jocular would then recognize L, R, G, or B subs in one of two ways.  First, and preferably, the Filter attribute in the FITS header would be set appropriately.  Second, Jocular will recognize the characters L, R, G, or B in the file name. I’d guess that Starlight Live is doing neither of these when you take subs.  You could experiment by manually prepending, say “L_”, “R_”, and so on as appropriate and then feeding the files to Jocular again. 

[RobertI]

4 hours ago, Steve in Boulder said:

Assuming you activated LRGB by selecting it on the lower right, Jocular would then recognize L, R, G, or B subs in one of two ways.  First, and preferably, the Filter attribute in the FITS header would be set appropriately.  Second, Jocular will recognize the characters L, R, G, or B in the file name. I’d guess that Starlight Live is doing neither of these when you take subs.  You could experiment by manually prepending, say “L_”, “R_”, and so on as appropriate and then feeding the files to Jocular again. 

Thanks Steve, that's a clear explanation. I was hoping perhaps by telling jocular which filter the incoming subs were using, it would tag them accordingly, but doesn't sound like that's how it works. I'll experiment a bit more with SLL and see what happens. 

To be honest, just setting up the filter wheel and getting it working was such a pain, it made me debate whether I really wanted the complication at the telescope - the whole point of this wide field setup is to be quick and easy!  

[Martin Meredith]

Hi Rob

Depending on which version of SLL you're running, SLL should automatically append _Red, _Green or _Blue to the filename when you specify these channels in SLL itself, and hence you don't need to do anything special in Jocular. Could you check your FITS filenames to see if this is happening in your version of SLL? Its a while since I used SLL and it doesn't work on my 2020 MacBook so I can't test it, but I know BillS has been able to do multispectral captures with SLL in this way.

It is still a pain to have to specify the channels in SLL via the interface rather than in the filenames, so it is not ideal for a quick/relaxes EAA session.... The alternative would be to use a different capture program that can also control the filter wheel in a sequenced manner, and which is likely to write the filter info into the FITS header.

Best of all would be to control the filter wheel from Jocular itself, but the only direct approach I currently support is for the SX filter wheel running on a Mac.

I can't test it myself, but the ASCOM support I added for filter wheel control does work, apparently (though there is a small bug with offsets that is fixed in the upcoming release). Did you try the ASCOM approach from Jocular with your Xagyl wheel? 

cheers

Martin

 

 

 

[RobertI]

OK, it looks like SLL is appending the red/green/blue to the filename. I tried stacking the images in jocular but it looks like it failing (I assume that’s why subs are shown in red) hence why it’s shown as B&W - I’m assuming I need to take some proper astro images to get this to work? 

 

Edited July 26, 2022 by RobertI

[Martin Meredith]

It looks to me that it has only been able to align 2 out of 10 frames (surprised it managed 2!), so it won't be able to synthesise colour. It needs at least one each of RGB. 

However, you can switch off alignment under the Aligner config panel, then it will be forced to stack them all, so you ought to see colour emerge.

BTW If all you're doing is feeding them into the watched folder from SLL you won't need to click on the capture icon (unless you have it set up in settings to have Jocular control the captures).

good luck!

Martin

[RobertI]

8 hours ago, Martin Meredith said:

It looks to me that it has only been able to align 2 out of 10 frames (surprised it managed 2!), so it won't be able to synthesise colour. It needs at least one each of RGB. 

However, you can switch off alignment under the Aligner config panel, then it will be forced to stack them all, so you ought to see colour emerge.

BTW If all you're doing is feeding them into the watched folder from SLL you won't need to click on the capture icon (unless you have it set up in settings to have Jocular control the captures).

good luck!

Martin

Many thanks Martin. I gave that a quick go over cornflakes this morning, and it did stack them all, but still shows as B&W - I think I'll take some better shots later on and try again.

Thanks for the pointer on the capture icon - that explains what I was experiencing!

[Martin Meredith]

Feel free to send me the log file by PM at any point. If there is an issue that will often help me.

[Martin Meredith]

For early adopters there's a release candidate out, installed using

pip install jocular==0.5.6.dev3

I plan to issue a proper release (ie the release you'd get by typing pip install jocular) at the weekend in case there are any bugs to fix beforehand.

Main changes include a streamlined interface, more flexible multispectral options, keyboard shortcuts (thanks to Steve!), nicer tooltips, choice of star extraction methods trading speed/robustness, auto-whitepoint, fractional binning, sub/FITs viewer, FWHM reporting.

Jocular also is now documented at readthedocs

cheers

Martin

[Steve in Boulder]

I've started playing with the multispectral features in this new version (0.5.6dev3), using some data from a few weeks ago.  Here's a taste of what's possible with narrowband filters.   All subs are 60 seconds, taken with a nearly full moon.  C8, 0.63x reducer, ZWO EFW and LRGBSHO filters, ASI533MM.   M16 is 6 Ha subs and 3 each of SII and OIII, shown as LHOS (i.e. Ha = red, OIII = green, SII = blue).  The luminance (L) layer is synthesized from the narrowband data.   M27 is 6 Ha and 6 OIII subs, shown as LHOO (Ha = red, OIII = green and blue), with L again synthesized.  You can start to make out the faint outer OIII shell, as well as the inner OII loops and Ha details.  

[Martin Meredith]

Thanks for trying these features out Steve.

Your Messier 27 is remarkable, showing what can be achieved with just H-alpha and O-iii filters. I've never been able to get the extensions of the main central disk let alone these outer components. I am inspired to dust off (sadly probably literally) my narrowband filters.

Its interesting that LHOO produces star colours that may or not be correct, but don't look too bad!

[RobertI]

On 02/08/2022 at 18:54, Martin Meredith said:

For early adopters there's a release candidate out, installed using

pip install jocular==0.5.6.dev3

I plan to issue a proper release (ie the release you'd get by typing pip install jocular) at the weekend in case there are any bugs to fix beforehand.

Main changes include a streamlined interface, more flexible multispectral options, keyboard shortcuts (thanks to Steve!), nicer tooltips, choice of star extraction methods trading speed/robustness, auto-whitepoint, fractional binning, sub/FITs viewer, FWHM reporting.

Jocular also is now documented at readthedocs

cheers

Martin

Just installed and had a play - some very nice new functionality and usability enhancements. Thank you. 👍

[RobertI]

1 hour ago, Steve in Boulder said:

I've started playing with the multispectral features in this new version (0.5.6dev3), using some data from a few weeks ago.  Here's a taste of what's possible with narrowband filters.   All subs are 60 seconds, taken with a nearly full moon.  C8, 0.63x reducer, ZWO EFW and LRGBSHO filters, ASI533MM.   M16 is 6 Ha subs and 3 each of SII and OIII, shown as LHOS (i.e. Ha = red, OIII = green, SII = blue).  The luminance (L) layer is synthesized from the narrowband data.   M27 is 6 Ha and 6 OIII subs, shown as LHOO (Ha = red, OIII = green and blue), with L again synthesized.  You can start to make out the faint outer OIII shell, as well as the inner OII loops and Ha details.  

 That's very impressive stuff Steve, the colour, detail outer shell are amazing. I tried my first LRGB multispectral last night with my "grab and go" EAA setup - a tiny 66mm refractor, a Lodestar camera which appears to be producing increasingly erratic subs and a SkyProdigy mount which stubbornly refused to align properly - the results were extremely poor, I think I will experiment a bit more before I am brave enough to share! However, there WAS some colour.  

[Steve in Boulder]

6 minutes ago, RobertI said:

 That's very impressive stuff Steve, the colour, detail outer shell are amazing. I tried my first LRGB multispectral last night with my "grab and go" EAA setup - a tiny 66mm refractor, a Lodestar camera which appears to be producing increasingly erratic subs and a SkyProdigy mount which stubbornly refused to align properly - the results were extremely poor, I think I will experiment a bit more before I am brave enough to share! However, there WAS some colour.  

Thanks, Rob!   The LRGB mode produces really beautiful results with open clusters and other dense star fields, which would be well suited to to your scope.  Targets like M33 might show nicely too.   So hang in there! 

[Steve in Boulder]

And speaking of open clusters, here's another experiment with the newest version.  For some objects, it may work well to skip the L subs and just use synthetic L from RGB data.  Here's M11 with just 2 each of 10-second R, G, and B subs.  The colors Jocular produces are glorious! 

 

[Steve in Boulder]

23 hours ago, Martin Meredith said:

 

Its interesting that LHOO produces star colours that may or not be correct, but don't look too bad!

So you're saying that the AP technique of using Starnet++ to remove stars and preserve their RGB colors prior to DSO processing can be left as an exercise for the reader?  😀

[Martin Meredith]

Your wonderful AP-quality M11 (1 minute, amazing) convinces me that I should add an option to ignore real L even if present 🙂

I have noted on occasion that RGB + synL produces 'nicer' colours, but not always. The key differences are

* L is sometimes actually C ie Clear, or even no filter, which brings in UV and IR components that might cause some colour imbalance

* the effect of weighting R, G and B channels to produce a broad-spectrum synthetic L is potentially different from actual L; giving the user the option of altering these weights could be useful 

Edited August 4, 2022 by Martin Meredith
depluralised

[Steve in Boulder]

1 hour ago, Martin Meredith said:

Your wonderful AP-quality M11 (1 minute, amazing) convinces me that I should add an option to ignore real L even if present 🙂

I have noted on occasion that RGB + synL produces 'nicer' colours, but not always. The key differences are

* L is sometimes actually C ie Clear, or even no filter, which brings in UV and IR components that might cause some colour imbalance

* the effect of weighting R, G and B channels to produce a broad-spectrum synthetic L is potentially different from actual L; giving the user the option of altering these weights could be useful 

It's possible now to ignore L subs by deselecting them in the subs table, but that's more work and less immediate feedback.  Here's a comparison using a different type of DSO: M16 with 15 second subs.  First is RGB + synthetic L, second is RGB + real L.