ONIKKINEN

Sounds like you are adjusting it right. Have you loosened the 2 screws holding the worm carrier bit to the mount housing? I mean the 2 in the bottom and not the 2 on both sides of the tiny setscrew. Those should not be overly tight, but also not quite finger loose to allow the worm to move in and out and not be fixed conpletely. In my EQM35 which is very similarly built (backlash adjustment looks identical) i got RA backlash down to maybe 5 seconds but not much better than that because like yours it starts binding. There needs to be a bit of backlash left as the innards start to bind well before its completely bound if you try to make it perfect. Yours could just be like this. Check the gearbox too? The little gears connecting the worm to the stepper motor can be tilted cause extra friction. The up and right trick might be enough for the troubles to go away though.

This is a bit of a problem. You need to always finish manual movements with the handcontroller by moving up and right. You need to first slew the star so that it sits to the bottom left, or wherever the left and down buttons take you (since the image can be inverted, flipped and all that) and only then center the star with the up and right buttons (and only those buttons, you go too far and you start again). This clears backlash and makes synscan work more accurately. I take it you have not read the manual, as this is what you would find in it.😉 But also if that 10s length at sidereal rate is actually so long and not a guess its a problem and you are nowhere near a well set worm but then there would not be backlash as its so loose. Are you sure you are adjusting the correct thing here?

On a phone screen in a well lit room looks a little bit dark, but not by a lot. Nice shot anyway!

If you put too much grease it will just get pushed out as the worm goes through all of the RA gear, so i would not worry about that. Unless you have some absurd mountain of grease in there that jams up everything but i doubt that. But more importantly why are you trying to set the RA axis backlash to be as tight as possible? The axis is constantly under tension so backlash does not matter. For guiding purposes a guide impulse is really just a speed up or a speed down of the worm, but it never really reverses rotation so backlash shouldnt be an issue (unless your guide rate is above 1.0x, in which case you should lower it).

How do the actual subs fare compared to previous guiding? That is the important part, not the prettiness of your guide graph. OAG guiding can look much worse than guidescope guiding because the guider is able to work more accurately - so report and attempt to fix more of the errors resulting in a seismograph. If your average FWHM values have gone down but guiding is worse, guiding is actually doing a better job. Other than that, take 3s exposures or longer with an OAG. If the seeing is really bad you might want to increase to 4s or even 5s. The guide log will reveal anything there is to reveal if you find it.

Beautiful image, rare to see detail as good as you have here. If only good seeing weren't so rare!

Give it a few years and nobody remembers what the issue with AI tools was anymore. I think a large part of the resistance to these tools and BXT in particular is how expensive they are so a lot of people will conveniently choose to be against them when they dont want to dish out 400€ to use them. Which is understandable because that's a mountain of money to most, but still kind of lame to think in the way that "i cant have it so i dont like you having it either". Im going to be honest i used to think that way about many things, but there is no benefit to thinking like this so i just stopped. 400€ in astrophotography is pennies in the end when you think about it... Kind of sad, but its an expensive hobby.

Looks like you got the hang of it already, not much to complain about. Maybe one thing, looks like you NoiseXTd the starless layer a bit too much, or BlurXTd the stars a bit too much. Either way the nebulosity looks a little bit soft compared to star sizes so the nebulosity could use some sharpening, or just a reduction in image size by binning x2. Most apparent in the first image where the difference between the sharp and very tastefully done stars and the soft nebulosity is easy to see.

https://www.youtube.com/watch?v=lAMyEpBcLV4 Have a look at this video from Cuiv, the lazy geek on Youtube, its a bit old now but the content is sound. ASTAP platesolving works the best, at least thats what the consensus seems to be. Also, NINA is free, open source, and pretty damn good so also recommend using that.

I will admit i have not had the chance to image M42 from dark skies, and i suppose i will not get the chance since it is around 20 degrees from the horizon here so that might play into the idea that i think its easy to expose for. But my most recent M42 image with 60s subs and an f/5 scope appears to have around 10k median ADU on a small selection box around the trapezium, and of this value somewhere around 1000-1500 is light pollution. So plenty of room to take longer subs, but not impossibly long. Was not a particularly narrow filter either, with around 25-30nm fwhm passes, so your mileage will most likely vary but shouldn't be too difficult if some thought goes into the exposure length. Actually the problem with f/2 scopes and the like is that you dont want to swamp by only x3, since the subs might be so short its a pain to deal with in the stacking phase. Then i would probably bother taking the second set of short subs.

Yes, mine has 2 separate DC5.5 x2.1 outlets with their own 3A fuse + the car jack with a 10A fuse. Looks like they have adjusted the pricing so that the new river max is close to the old river 300 in specs in everything but wattage but 200€ more pricy. Of course also conveniently pulled the river 300 from sale. You could try to fit an adapter from the car plug to the small DC 5.5 plug(or multiple plugs) and solve the issue. The wattage seems good otherwise with the river 2.

Regulated to 13.6v all the way to the end. lowest i have gone is down to 20% charge and no issues with voltage dropping like with normal batteries. Mine is no longer being sold, the new river 2 advertises 12.6v instead of 13.6v and some other changes so there may be more changes that affect performance. You can pick these up at Verkkokauppa in Jätkäsaari by the way, amongst a mountain of other brands. Easy to return if it ends up being unsuitable for Finnish weather.

Oh yeah, with older cameras for sure. Newer CMOS with close to 1e- read noise and decent fullwell will swamp read noise by at least 3x while still not saturating the core with a carefully chosen exposure. At least with my IMX571 its the case and i dont have to think about it too much. For very dark skies such as yours and a very narrow Ha filter might still be an issue in the fullwell department with the core though.

Different sub lengths can be useful or necessary outside of high dynamic range targets. Lets say its windy and we are imaging under a Moon or light pollution so short subs of 60s are preferable as they swamp read noise effectively due to the sky being bright but have smaller chance of wind caused loss of exposure. Then lets travel to dark skies under no Moon and this time no wind. Now i might take 240s subs to cover read noise and without wind to ruin the subs there are no downsides. Sticking to a single sub length is doomed to be a compromise in some cases, its better to adapt the exposure to the conditions in my opinion. But different sub lengths in a single night? Not sure i see the point, even for M42.

If you have large stacks of subs you really want to try stacking with siril. I tried with 4000x 6MP subs where writing the temporary files, registration, normalization and rejection stacking completes in under an hour with 16GB of RAM and an I7 6700k. APP took 7 hours and PI never completed the process although it tried for several hours... Siril is the go to stacker for crazy amounts of subs.

Oh, my read between the lines detectors are under maintenance on mondays 🤣 The xx60 or xx60Ti series cards are typically the best bang for buck, but its hard to say at any given time because the GPU market never really recovered from the past few years so prices and availabilities change fast.

Quadro series cards are terrible value for money, you would be better off with just about any normal GPU instead. CUDA cores exist in all Nvidia GPUs, its just their own technical term for something the GPU architecture uses, dont worry about it too much. Take a look here for GPU benchmarks, higher number is better: https://www.videocardbenchmark.net/high_end_gpus.html Maybe an RTX 3070? Even the RTX 3060Ti would be quite nice and not that expensive. I would advice you to not spend as much as you were planning to as the highest end GPUs are not good value for money. I have an older GTX 1080 which youll have to scroll down to find in the list, but it does all the russell croman actions just fine. Star removal less than a minute every time.

Hmm, looks like my model is no longer being sold. Looks like this: https://eu.ecoflow.com/products/river-portable-power-station?variant=37254607863972 The river 2 looks like a newer version with LiFePo4 cells, i think mine has good old lithium ion (not so sure about that though). So should be an upgrade all around to mine, at least when it comes to total lifetime and overall weight which are the selling points of the fancy new LiFePo cells. Either way something like the river or the bluetti or really anything with similar specs will work very nicely with AP kit. Should probably try and get something that is as local to you as possible as shipping batteries this big for potential warranty issues could prove to be a headache.

Visual or imaging? If imaging, what type of imaging? For planetary and lunar, not important of course.

Russ Croman interview about BlurXT, found it interesting and answered some questions i didn't know i had:

Thanks, if you have PixInsight the spectrophotometric colourcalibration tool in it can do a much better job at colour calibration with odd filters like this one, since you can input the bandpass widths and locations to it. Couldn't do it this time as my trial license just ran out but it worked great with no additional tweaks required on a horsehead and flame image i took with the filter a while back. Overall seems like an easy to use wider bandpass narrowband filter that also looks not so narrowband-ish in the end because it also passes the extra blue.

Took this last night from inner city skies and the full Moon in the sky. Went for a 4 panel mosaic but there is only noise outside the brighter regions, so they are cropped out. Approx 50min integration all considered, with 60s exposures through the Antlia Triband RGB Ultra filter passing Ha, OIII and an additional blue line for star colours. The colour palette is whatever Siril photometric colour calibration made of it, looks somewhat natural-ish and believable? I don't know, not a proficient nebula processing person myself. This was pretty much the worst possible imaginable scenario short of it being fully overcast, high wind which the newtonian doesn't like, high cloud so terrible transparency, Bortle 8, Full Moon, target at 20 degrees of elevation. The conditions almost literally could not be any worse, so maybe a little surprised that it turned out into an image in the end. Can you see Orions belt? Its in the picture below . That altar of light fully lit car park also nicely shines straight inside the open tube, but surprisingly did not cause any issues, flocking is doing its job it looks like.

I have an Ecoflow river 300 with specs pretty much identical to this one you have linked (identical to the point that they may be the same actual battery in different clothes). Mine has never been even close to 0 for a single night and usually could supply power for 2 or 3 before running out, not that it matters since it recharges so fast. Have used mine maybe around 100 times now and see no signs of slowing down or loss in capacity (used in -27 to +15). This will be exactly what you want for mobile AP, well worth the money!

Clear outside shouldnt be your only tool to check weather if you want to have a better guess on weather. Also shouldnt be used to check more than a couple of hours ahead because its not a fortune telling service. Check "good to stargaze" (app) too, and on top of that check a few normal forecast services and draw a conclusion from what all of those have to say. Sometimes they all disagree and none are right. Sometimes they also get current and previous weather wrong, have imaged many times under "100% cloud" when in fact there where hardly any. Best just open a window and see the weather yourself, seems to work best.

Stellarium also exists in a web browser format: https://stellarium-web.org/