ONIKKINEN

In the Post-Calibration tab of WBPP, go to the top right selection box "Exposure tolerance" and set that number to be higher than the difference you have in your subs. For example if you set it to 30s images within 30s of each other will be stacked into a single master light so in your case 30 and 60s would be stacked together. And yes, you can keep adding subs to year old projects. As long as you calibrate everything with their own calibration frames it really doesn't matter which year the data was taken on.

Reading your situation it still sounds to me like the overwhelmingly easiest and cheapest option would still be to just set up guiding. Any 30mm guide scope, mini-pc ziptied/velcroed somewhere on the setup (need not be fancy) and you are set. Any guiding will be better than no guiding at all, no matter what you might think about the backlash of your AVX. So without guiding you are rejecting 25% of all subs and its still acceptable? Sounds way too much for normal operation to me. Scrapping 25% each night would be a disaster in my books. Like you said you have 5'' error in every sub and you find that acceptable, but guiding results in up to 1.2'' error so to me it seems obvious that you should just keep guiding as its 4x better? Who cares about backlash if the end result is 1.2'' RMS at a resolution of 4.7''/px, that is excellent guiding for the setup. On the last part, if there are mounts that can do better than yours (yours sounds like a really good copy of a mount). There are mounts with encoders, but these are very pricey: https://www.teleskop-express.de/shop/product_info.php/info/p12834_iOptron-GEM28EC-with-iPolar--Case-and-LiteRoc-Tripod.html Again, by far the simplest and most cost effective option is to just guide.

See if yours is silicone glued to the mirror cell? Mine was from 3 points on the side connecting to the clips and on the bottom where the little nylon pegs hold the mirror in the sell. Youll need to get rid of the silicone somehow if thats the case, with box cutter or similar. Careful not to scratch the mirror of course! Also, if that seems like too much trouble you dont have to remove the mirror from the cell to clean it.

Honestly, Siril goes really far on its own. My 2 cents would be to stick with it + Gimp for now. Or maybe consider subscribing to Photoshop. At 12€/month its an absolute steal of a bargain and will take you more than 2 years to become "more expensive" than PixInsight which i think you might not be able to use efficiently at the moment as its quite challenging to use although here i inject my own bias in to the mix as i learned to use other tools before PI. Photoshop has many included plugins that are easy to use and can work well with astrophotos (like Camera raw, Smart sharpen, Unsharp mask, noise reduction, lightroom etc). Siril has an amazing background extraction tool, simple and effective Photometric color calibration tool and easy to use stretching tools with a simple interface where you actually see what you are doing while you are doing it (as opposed to PixInsight). The newest version can also do non-blind deconvolution which will sharpen your images if there is anything to sharpen while attempting to not boost noise. You can also link Starnet++V2 to it and run it on linear images to create a starless and a stars only image to play with further in Gimp or Photoshop should you choose to do that. I would say get to the bottom of the basic workflow: which includes well calibrated data, well stacked data with obvious outliers removed using the "plot" tab in Siril, background extraction, colour calibration and stretch. All are very easy to do in Siril and result in an "almost done" image!

More reprocessing, this time only M82: Slightly different looking maybe? Stared at the image far too long to tell the difference any more.

Looks professional, could imagine an astro gear manufacturer stamp on the side and a 50€+ pricetag on it. But Finnish winter eats plastic parts, especially those that are under any tension so would probably not dare use it myself. I am guessing you dont have to worry about something like that so looks good to go.

You definitely have some IFN! The lower part will look like it connects to M81 as an extra spiral arm if given more time. But that might require a really unhealthy dedication to one image from Bortle 8. But still, IFN is IFN and you absolutely do have it here which is an accomplishment on its own from inner city conditions.

Truly mind bending numbers at play here, love to see it. Now i have fallen down the Quasar search rabbit hole to see just how long did some of those photons spend on the way to my camera sensor.

Using NINA myself. Everything works as intended (some user error not included) and have been perfectly satisfied with it for all my needs. I use an old version from 2021 but since everything works just fine i am not going to update it.

Great images as usual!

Really sharp! Not sure i would call this oversampled no matter what the theory says. My eyes seem to like it very much!

You are probably right with the IFN being too prominent in the background. I am desperately trying to make it observable, but probably some of it should not be so (at least so strongly).

Reprocessed the image i posted in March from scratch: I much prefer this one to the last one posted here: Let me know what you think! -Oskari

I have been feeling the need for speed lately which has manifested itself in a desire to get a 12'' f/3 carbon newtonian. Would cost an arm but maybe not all of a leg to make happen. Also this would be just about the largest and fastest possible scope that would still be viable for mobile use without an observatory. Not that i have an arm or half a leg to spare for the costs at the moment but hey we are dreaming here 😉. Or a RASA36, or an 8'' refractor, Takahashi CCA-250? I'll stop here or i will list every large aperture imaging scope ever made.

Very nice, especially the last one.

The second image (one taken on 23/4?) looks quite a bit worse than the first one. Not obvious from the stats, since offset is 256 we have around 1000 ADU in the first night which gives us 250 electrons with gain 100 that has an e-/ADU rate of approx 0.25. The second night is then somewhere around 1200 ADU/ 300e- so not an earthshaking difference, but both are pretty high already. Im just looking at these in Siril autostretch and there is a noticeable difference when i blink between them, the first night has an obviously brighter M51 and stronger stars than the second one and indeed by measuring the number of detected stars i see a drop off a cliff from 640 stars to 400 in the second night sub. Fewer stars, darker looking target, a little bit more signal in the same sub length and filter. Sounds like terrible transparency for the second night. It can really be that bad if there is some thin high cloud, excessive humidity, aerosols like smoke or pollen (we have a pollen apocalypse here at the moment for example). All of that will reduce the actual signal you want but still make it seem like you are getting usable signal since the frames have a familiar looking ADU count on them just from local lighting conditions. On flats; you can drop darkflats if you want to and use bias or even the dark master as a darkflat. You can also subtract offset by some other method, i know APP does some kind of pedestal thing for flats and if i recall correctly WBPP in PI also had an option like this. Its important that the offset gets removed, just not very important how with how little dark signal there will be in flats. In principle its the same thing for your lights, you could drop darks and just subtract offset. With 180s lights you are getting less than a tenth of an electron per pixel on average if you cool down to -10 so up to you to decide if that's worth taking darks over.

Thank you! The usual; 8'' f/4.4 newtonian + TeleVue Paracorr so effectively f/5

I did mention in my past M106 post that it would be the last image unless i forgot something from the past season. Which i did, this one: 132x 120s presented here at around 1.1''/px. I think its worth a full screen click for the galaxy core alone Captured early April in decent seeing and at the time i didn't like how i initially processed it so i just left it. Still have an extra 4 hours on this with the Antlia Triband filter which might end up as an Ha layer for this data one day. Still learning how to do that properly so did not make this cut. This process is sitting much better with me, but may have overdone sharpening on the core. Comments and so on very much welcome as always. -Oskari

Typically they are quite weak with maybe a little bit of green. The massive flare back in February really did look like many images with vibrant green everywhere in the sky, but that one also had a rare red component which made the sky look like it was literally on fire. But that was more of an exception than a rule, naked eye red aurora is quite rare even at 60N where i live. The light show week ago apparently was similar, but i was in a cloudy spot then so couldn't tell.

Hmm, the differences really do seem suspiciously small. If i had to guess which one had 5x the data im not sure i would make the right call blind. Your flats are overcorrecting by the way and that could throw a spanner into the works with normalization of the subs which will ruin all hopes of getting the best possible image especially if conditions are different on both nights. Without working normalization adding more subs might not necessarily improve the stack. Maybe something to do with it? Also looks like you have some pretty heavy light pollution judging from the levels of the stacks. Was one of the nights just with better transparency? I have seen transparency affect an imaging locations bortle rating by more than 1 (from 4 to 3).

Difficult to measure objective things about noise when the data is stretched, but to my eyes the image with both nights is noticeably better. Not that i know how to make those measurements objectively anyway . Could be just a difference in level of stretch of course, but just a preliminary eyeball-only measurement makes me think the left image has a much better signal to noise ratio. The core parts of M51 are incredibly bright so i dont think there are obvious SNR improvements to be seen there. Look at the tidal tail parts for example, they are smoother with significantly less RGB noise. Also many of the Ha regions and bright blue clusters look tighter in the left image. By the way, when you say sticking the 2 stacks together do you mean actually just stacking the stacks instead of the data from the 2 nights? Stacking stacks will be less effective than integrating the subs to a new stack.

I will admit i have not paid any attention to trying to get a specific offset pattern with mine since i collimate via laser. I only check the secondary is roughly central when i have removed and reinstalled the secondary for some reason, but the top image looks more familiar to me.

This is what i would do, as a newtonian imager a "dont try to fix what is not broken" mentality is good. You mention that everything is perfect in terms of collimation and tilt so is this really important? You have a real chance here to make things worse with fiddling - just leave it be and enjoy a well collimated newtonian. But anyway, looks like you just need to center the secondary under the focuser like you already concluded at first. The only thing this achieves is that you have less vignetting. Simple to do but again i would not bother. A centered secondary is no requirement for collimation by the way. Its just good to have since vignetting is lost light.

If a concrete launch pad built here on Earth gets atomized by the engines i am left wondering how is the upper stage ever going to land and lift off from the Moon or Mars? Yeah ok fewer engines on the upper stage and not nearly as much thrust required to lift off compared to Earth, but still it all seems way too risky. The engines would excavate a massive crater on the way down and on the way up so twice the risk of some regolith rich exhaust.

I tried not to look at your, or other images for reference during processing so that i dont introduce some bias on what is noise and what is actual detail because it was not at all clear when looking at the initial data. I wonder if i would have just excluded the tidal tail if i were to process the image without knowing it was there in the first place, maybe i would have knowing now how faint it is. Negative from the green channel below where it is just about visible: