AKB

Essentially correct. You don't need to synthesize an L file – Jocular will do that internally itself. You can, no doubt, use the Jocular library for debayering, but the simplest approach is to use "super-pixels", which essentially use a 4x4 matrix (typically of RGGB) to generate a single (RGB colour) pixel, thus binning the image x2 at the same time. This is quite effective for modern CMOS OSC which tend to have small pixels and too many of them for Jocular to be entirely comfortable (in terms of operating speed.)

Thanks, Mike. Nice to have the darkness back and the scope ready (but nothing going today!) Hard to say. I've zoomed in a bit, but it's a bit noisy and you can see from the square stars that the Ultrastar's big pixels (6.45 microns) under-sample a bit (which I suppose means that my focus and collimation is actually not too bad.)

Well, since you ask... NGC 1055 – two shots here, one zoomed in, the other widefield to show M77, since together they are a binary system. Discovered by Willam Herschel, it look somewhat lop-sided, allegedly because one of its spiral arms occludes the upper part of the central bulge. NGC 7479 – Another of WH's discoveries, this is a Seyfert galaxy (having strong emission line spectra from its nucleus.) NGC 1169 – barred spiral, and yet another WH discovery NGC 925 – (The Amatha galaxy) a barred spiral, and a member of the NGC 1023 group.

Lua can link to anything, so I should be able to use that, although you pay the price in footprint of the code. Lua is tiny, Python is not. This is really simple. The algorithm called SCNR... https://www.pixinsight.com/doc/legacy/LE/21_noise_reduction/scnr/scnr.html If you invert the image, you can also use this for removing magenta star colour in Hubble palettes, and the like.

My language of choice for scripting is, in fact, Lua. This rather cuts me out of tinkering with the internals of Jocular, but is perfectly fine for separate scripts like this. Would be interested, nonetheless, in what functionality you may add to your script. Tony

Here's my stab at 29P from last night (Nov 4) in Aurega. The many stacks don't add much after the first few minutes, but I wanted to see if I could detect motion. Indeed, looking at the individual frames there is a small shift over the whole 15 minute stack, but not enough to make a significant track visible here. Tony.

Arp 113, small galaxy group in Andromeda. C9.25 with Hyperstar and Ultrastar camera, giving f2.3 and a FOV in this view of 40' and 2.5" / pixel. Taken on Nov 4, it's the group on the left hand side of the image. But there's so much else to see here, including other galaxies, quasars, etc., all so much more understandable because of Jocular's plate solving and catalogues. I've highlighted a few of the most, and least, visible. Happy to see that PGC 3593057 is Mag 19.0 Tony

Monday, Nov 1, was an observing session for the local (Abingdon) astro club. We're still doing this via Zoom, and I for one could not be happier with this approach. It allows multiple locations – almost essential with the UK weather – and there's almost always someone with something to see. Jocular is, undoubtedly, the weapon of choice for these sessions. I have recently acquired (secondhand, from here) a different mount (Mesu e200) which has allowed me to put together a dual scope system and save the not inconsiderable trouble of swapping between them. I have a 5" APO and a 9.25 SCT on there at the moment, but apart from balancing, hadn't done some essential stuff like align both scopes with the guide scope, or collimate the Hyperstar that I use on the SCT for EAA. Equally rashly, I'd had to change the electronic focuser since the previous one was tied to the other mount electronics, so hadn't had much time to practise with that. Also, I couldn't find the power cable for my Atik-460EX mono camera, so used, instead, the trusty (but smaller, and USB-powered) Ultrastar. OK, excuses over, we had a great session, between all the different contributors. My targets included: NGC 891, edge-on spiral in Andromeda NGC 1023, the Perseus Lenticular galaxy NGC 1514, planetary nebula in Taurus Messier 33 Messier 45 Comet 29P My collimation and focusing issues were such that, although they gave passable results on the night, I'm too embarassed to share that night's shots, but, wonder of wonders, the weather for a few nights after has also been kind to us, so I've sorted that out, revisted the above, and also added: NGC 1169, galaxy in Perseus NGC 7479 in Pegasus NGC 1055, galaxy in Cetus Messier 34 ARP 113, peculiar galaxy in Andromeda IC 405, Flaming Star nebula in Aurega Messier 76, plantary nebula in Perseus I'll post some of the more worthy targets in their relevant sub-forums shortly, but just put here a crowd-pleaser from the Zoom session, which also demonstrates that my collimation on the Hyperstar is not yet quite perfect (nor the diffraction from the camera cable.) Nonetheless, it does show some good nebulosity in just 12 x 30 second exposures. Tony

Er, um, ... I suppose I take the blame, then? Fully agree that OSC needs a rethink. For me, the ideal solution would simply be a separate process which watches files created by the camera software (which I'm very happy with remaining separate, partly because I can dither and auto-focus, and you're not going to put that into Jocular for a while!) The process would then do the debayering (and possibly binning) of choice and spit out the separate files that Jocular needs. This seems to me to be altogether the cleanest approach. It would also allow, perhaps, a bit of RGB processing which help with OSC – particularly the suppression of excess green. I tried the .dev version recently, but, as you say, it's not complete, so reverted to 0.4.5 (it's SO easy - thanks) and have had great fun with it recently, including the use of flats. I'll post some recent observations shortly. Tony.

I had this challenge with my Mesu recently. I ended up drilling three holes in the old top plate (there was room in between the adjustment bolts. I didn’t think that a single bolt would suffice to stop the possibility of rotation. Tony

This is a bit less of an issue with the new Mesu e200, as it’s a lot lighter. I still like my Avalon M-Uno, though – no counterweights, no meridian flip – with the same belt drive arrangement as the Linear. I haven’t checked the belts, but I’ve not seen any issue, so I’ll leave well alone. I’ve also had great service from Avalon, because I shipped it back to them (pre-Brexit, thank the Lord) to get it upgraded to a dual Losmandy head. Tony

Thanks both. I’ll put the 120 and guider on the fixed clamp and the wide angle hyperstar (which has some mirror flop anyway) on the JTD.

I just bought one of these myself. It’s built like a tank. The specs say it’s rated to 9kg, but that must be just notional. I take it that your RASA plus scope plus focuser plus… actually comes in at quite a bit more than that? I’m trying to decide whether to put the Esprit 120 or the C9.25 with Hyperstar on it. Tony

Looks great. Where did you find this? All I get when I search is Bahtinov masks….? Thanks! Tony

Just to add a bit of consolation… this is not a problem with your understanding, it’s just that digital signal processing IS complicated. Mathematics is the right language to describe it and make decisions, as @vlaivand @Martin Meredith both know well. So when we resort to more qualitative descriptions it becomes confusing. Rest assured, though, that the differences between the methods being described are generally small, and there are undoubtedly more significant impacts to your final image from whatever you choose to do further down the processing chain. Tony

With some recent clear nights, but close to full moon, I've been using the opportunity to learn more about my new mount and how to cope with a meridian flip... not that I've actually done one yet! I've just yesterday switched from using Nebulosity for image capture (which has been great for the last five years with a mount that doesn't need a flip.) But now I do need to flip, and want to autofocus and plate solve (as part of the flip) so I'm trying APT. Last night (22 Sept 2021) just past full moon, I did my first run with autofocus and acquisition, right up until the target arrived at the meridan, but stopped there, since I haven't really set any parameters for the meridan in either the mount or APT, and I haven't yet looked at plate solving. Any advice on the combination of APT and SiTech is welcome, but here's the (uncropped) image: Esprit 120ED ASI 294MC OSC with Altair quadband filter 18 x 5 min subs (1.5 hours total) Thanks Tony

My final attempt, for the time being: 17x2m + 47x5m (total of about 4.5 hours - my longest ever – over three nights) again with an essentially full moon (and high cloud from time to time). Certainly, another improvement in SNR, but, on the whole, a bit disappoiting... Tony

Thanks for that. A bit off topic, but how did you fix the focuser to the vanes?

I’ve always wanted to try this, although for EAA rather than planetary. You have a helical focuser? How do you align? Tony

A surprise opportunity last night to extend this image from 17x2m to 23x5m, so nearly two hours, in all. However, this was with a 95% moon in the sky. Incremental improvements clearly visible: ...still a LONG way to go, though, to achieve the nirvana of the original inspiration. Tony