ONIKKINEN

Look up ASTAP platesolving, its what you are after. The H18 database is like a gigabyte, not a terabyte and i dont recall platesolving ever taking more than a couple of seconds (ignoring a few user error type situations...).

Lovely, i really like the diffraction spikes. Adds character to the stars that is sometimes missing from RASA images where the stars are very much a secondary part of the image compared to the not-stars part.

Its back up and updated to 1.2.0-beta1: https://siril.org/download/2023-02-24-siril-1.2.0-beta1/ Looks like an enormous update to Siril. Added features include, at least: Binning, clamping for lanczos-4 interpolation (no more dark star artifacts), starnet integration for separate star and starless processing, reworked deconvolution and PSF measurements and im sure much more. The price to performance ratio of Siril just keeps on getting better!

The EQM35 is an EQ3 in disguise, it has no bearings on either of the axis and so is pretty much unservivable junk that will not work properly. Both of the axis are supported by plastic shims and lubricant and thats it, backlash and wobble a plenty! The EQ5 actually does have bearings and is generally much more robustly made and so shouldnt be compared to the EQ3 and 35. Also very similar price and weight to the EQM35, so there are hardly any reasons to get the 35 instead of the 5. On the Exos, sorry, cant say as dont know too much about it. Used to have an EQM35 and can safely say its not the mount you are looking for, nothing but regret in my mind as i think about that purchase.

Why not the EQ5? Cant say about the Exos-2 but you definitely dont want the EQM35.

How big of an issue is a satellite strike for professional astronomy really? Is it only a critical issue when the satellite happens to fly directly over some tiny target that just so happens to need that exact moment of clarity, like i dont know, exoplanet transits or something like this? Genuinely dont know if its such a big deal. But the speed of development is the worrying part here for sure. 10 years ago mass launching and more importantly: mass launching and re usability at a low cost was not on anyone's mind and now its just another day in the industry. Where are we 10 years from now? Kessler syndrome will happen, the question is when and i think its not too many decades off if more private entities want to get a piece of the orbiting internet money generator pie. Also what worries me is that why is this necessary and is it really such a good long term investment? Fiber optic internet is faster than satellite internet simply because the distances are shorter across the ground than first doing a hop to 600km upwards (the wrong way) and then several similar hops of the signal between satellites, at least the speed thing is valid for more or less local connections (like within europe lets say). Most urban areas in the developed world already have good fiber and that doesn't fall out of the sky every 7 years. Areas around the world that are still developing will want to get fiber infrastructure rather than a private internet owned by the richest person in the world that can be switched off or reduced in capacity at will...

Clipping will remove the trails from images so not really worried about that. From a kessler syndrome point of view, maybe a bit worrying but its only a matter of time that becomes a reality anyway.

Depends on the location i am shooting from but i try not to image under 40 degrees due to seeing and light pollution getting pretty bad there in most of the locations i visit for imaging. In the case when a target starts at a low altitude but gets higher during the night i will start with another target that is higher in the sky and switch over to the primary target once its high enough. This way i always try to get the most optimal quality data possible from every night out with the scope as clear skies are so rare i really dont want to use the precious time poorly. Of course some targets do not rise that high and they need to be imaged at as low as 20 degrees and in this case i try to travel to a location that has the best possible southern low sky since light pollution is multiplied greatly by the low elevation. For different sub lenghts, i dont pay it much attention. I shoot either 1, 2 or 4 minute exposures depending on how dark the skies are, filter used, and if its windy or not. I already know what ADU numbers to expect in the background for read noise to be swamped x3 (the minimum i aim for even if windy) so i just use 1,2 or 4 minutes based on that. Differing background levels between different nights or during the same night are of little concern because normalization will take care of that in the end. But i do try to not mix awful data and great data for the same stack as the bad data could lower the SNR in the end. For example i will probably not bother shooting a target during a full moon if i already have 3 nights from a borle 4 sky without a Moon.

No need to split afaik, just split the iamge that the stacker spits out before processing anything on it and you get the most bang out of the binning process. (integer resample = Bin)

Thats a nice M51, but i think there is more to be taken out of the image if you do somethings a bit differently. Looks like BXT has only tackled the core/very high SNR regions and so there is a "disconnect" in the visible levels of detail in the sharp core and soft everywhere else on the galaxy. Try integer resampling at least x2, probably x3 and you will get a much sharper image. BXT will not sharpen the soft parts of the image because from its perspective the too high a resolution image has nothing to sharpen. That said, my limited understanding of BXT is that it prefers not quite properly sampled images to properly sampled ones, so you might want to be a little bit oversampled for BXT to do its thing best. But still at least 2x or 3x integer resample will work.

You need a proper dark library and a bad pixel map, PHD2 should guide you through that. On top of that you need to set the minimum HFD value to something larger than a hot pixel but smaller than an actual star. What that value is depends on a number of things but if you have it set to 1 pixel increase it right away. * and bin the camera to something reasonable. 1x with either camera is far too high a resolution.

Yep, that's the best plan. I keep a folder of calibrated subs for every work-in-progress type target i am shooting so eventually when they are ready for stacking much of the work has already been done.

If the scope was left assembled during this time the flats should work. I have no such option and take flats each time and they always work, it doesn't take too long to take the flats so its time well spent as far as im concerned. But with a newtonian you have other things to worry about than whether the camera was removed, namely the mirror which can and should be able to move (but not accidentally, and not that much), focuser which might sag and the tube itself which might deform under different orientations/temperatures. All issues that result in any of the parts between the primary mirror and the camera sensor moving even a tiny little bit between taking the lights and flats will result in weird gradients (such as this ring). Its all wild guessing at this point, but you have one way to see if the flats worked at all and if they only worked for some of the data. Check the calibrated frames and see if this artifact appears in all of the subs or just some of them. If some of the subs have this ring and some dont, it means you have some mechanical problems somewhere in the scope that lead to flats and lights not matching.

Did you take the flats at the end of the session? Rings like these come from flatframes not matching light frames because they were taken at different times/different camera orientations/different collimations (100 little things in newtononians = always take flats for each night). Not saying its definitely caused by flats, but sure looks like it since you mention they are not present in the light frames.

You should have mentioned that filter as the first thing of the post. See the spectrum: Blue and cyan is passed, deep green-yellow-orange is mostly blocked. So the colour palette will be skewed, as the input data was skewed. You might want to just tweak the levels manually to get the palette you are looking for.

What kind of curves and what does the image look like if you dont do the curves but just do a simple stretch after SPCC?

What did you do to make it so cyan? Have you tried colour calibrating with SPCC, it churns out a well balanced image every time. Unfortunately my PI trial ran out and my bank account balance disagrees on the importance of buying the software so cant run it through now, but i am sure SPCC would not make it so cyan. The problem there is that the colour palette becomes quite boring and you'll have to selectively boost the blues quite a bit in case you wanted a typical neutral looking core and blue outer regions with red Ha poking out here and there. In that case you dont want to apply saturation globally, you want to avoid adding much yellow/orange saturation or the core becomes deep fried but instead apply saturation to the bluer and redder (Ha) parts of the image. On a side note, the image is way too big at 8k pixels in the wider axis which is also why the file size is ridiculous. You can safely at least bin x2, probably more, and lose nothing of value. Also helps a lot with your noise (only noise seems to exist in single pixel level detail).

Nice to see off the beaten path targets, and great job with the IFN! I accidentally found IFN here in this exact same field of view when searching for a high declination target to shoot with a non-cooperative mount. Swore to finish that project but never did for some reason. I think i put up to around 10 hours on it in 2021, mostly from not so great skies though and back then for sure did not know how to deal with the data (still dont, but now i know the extent to how i dont 😉). How much time did this take with the RASA? Thinking of maybe continuing where i left off, would be a shame to let the gigabytes go to waste.

Not familiar enough with the 183 to say if its something that can do without dithering, but as mentioned above the newest very clean IMX571/533 cameras can work without dithering, provided that the polar alignment is competently done, darks are well matched (and maybe that there is no significant cone error). The Siril background tool dither option is there to dither the background samplers in case you end up with a posterized result with obvious harsh transitions between areas of different illumination. Cant recall if i have ever needed it, but safe to say it does not cure walking noise nor is it intended to do so. On the topic of the background tool, make sure you have cropped the incomplete edges, dont place too many samplers and that none of the samplers are on stars or nebulosity. Put the preview mode to Histogram and negative to get the best view on faint stuff. Dont trust the automatic sampler placement!

Saturated stars are not useful for FWHM measurements, and of course in did not use them so the exposure is perfectly valid. Round stars are easy to get and thats not the point of guiding at all, the point is a round and small star. Equal errors in both RA and DEC at the same time result in a round star, yours are so big there must have been a sizeable error or terrible seeing, possibly both.

Have no say in the mount matter, couldn't afford any of the mounts discussed in this thread 😬 but obviously want one one day. But on the fits file, are you sure its a good idea to not guide with the mount? Looks like you have somewhere in the range of 3-4'' (or even more, depending on software used to measure) FWHM stars, which is unexpected with a high spec instrument such as this and wouldn't believe for a seconds its optical quality related. Honestly this is what i get with an 8'' newtonian on an AZ-EQ6 on an average-a bit worse than average seeing night guided at 0.6-0.8'' RMS, so either you really do want to guide or the seeing was horrendous this night. My 2 cents anyway. Stars do look round but just too large to believe its doing a great job without guiding.

Walking noise is really difficult to get rid of if you let it build up to the point of it being a nuisance in an image. The best way to reduce it, you guessed it, not having it! If you keep getting more data and you "overwhelm" the earlier sessions with well dithered subs you will get rid of it. But software solutions are all a pain, your best bet is to try and selectively desaturate the walking noise with masks first before trying to denoise it. Often there is a single colour that is most visible in the walking noise pattern that once removed takes much of the problem out with it (like purples for many DSLRs, maybe greens for some OSC cameras). Of course easiest to do after star removal with Starnet/StarXterminator so that the stars are not in the way. Then once desaturated you can try to denoise the grain but honestly its not something that can be trusted to do the job and you will likely end up with an image that looks like a bit of a painting if and when the denoise goes too far.

Speechless! What an image.

There is a real sense of scale and distance here with the bright foreground star and its diffraction spikes covering more area than an entire galaxy made up of billions of stars just like it. Great image! Also have noticed the best seeing always occurring with high cloud and low transparency. If i recall the meteorological explanation it was something about stable skies being helpful for cloud formation, so good seeing always has clouds just around the corner. @gorannif your skies are as baltic (unpredictable) as mine these good seeing nights are often forecasted as fully or partly cloudy, even during that sort of clear spell so its difficult to prepare.

Oh i get it, my galaxy season target list will last me at least the next 3 years of galaxy season 😅. Too much out there this time of year and so little time!