ONIKKINEN

766 x 120s, around 50/50 split between UV/IR cut and an Antlia Triband RGB filter. Taken with an 8'' newtonian, TeleVue Paracorr, and a RisingCam IMX571 OSC camera. Resampled to 75% of original resolution, so roughly 1'' per pixel. The UV/IR cut filter data is all pretty good from better than average seeing nights and little or no Moonlight. The Triband data not so much, with some real uphill battle nights and 10+m/s winds and/or Moonlight. I think the UV/IR data is doing most of the heavy lifting here so not that big a deal. Imaged over 7 nights in total, 2 of which were in April 2023, 2 in February 2024, and 3 in March 2024. Haven't gotten a chance to image in April of this year mostly due to weather, and its looking like that is not going to change as the Moon is rising and the season closes in around 2 weeks so this will likely be the season closer for me. This year was significantly more windy than the 3 past years i have imaged, i think this might have been a 40+ hour image had the conditions been better but still shouldn't complain, its not like 25h is a short image. Calibration and stacking in Siril, processing in PI and Photoshop. I used a 2 stack method for this one, with the first stack containing all the data and the second stack containing only the Antlia Triband data. The Triband only stack was used as an H-alpha enhancing layer in Photoshop which is a subtle but noticeable boost to the bright emission regions. Feedback welcome -Oskari

I've no heaters, the primary is so far down the tube it really doesnt get dew. The secondary is kept dry by a dew shield and flocking applied to the back of the mirror (so it doesnt radiate heat away as much). I think the fan also helps with dew prevention since there is constant airflow over both mirrors and dew is less likely to stick.

I'd go with the 8" newt, but then again as a newtonian user myself i am biased. Something to keep in mind is that you need to install a fan on the primary mirror to keep the scope acclimated throughout the night. Temperatures can easily drop 10 degrees at night here in winter, which is too much for just passive cooling to do the trick. Its not an expensive thing to set up but one more thing to fix (just a computer case fan + some DIY for mounting and power). I am planning on getting rid of my Paracorr because it has some field curvature over an APS-C sized chip, but i think it would be very good for your 533 cameras. Let me know if you are interested in that if you do decide to go for the newt.

Bortle 3 is excellent, so no point in a light pollution filter unless your camera is astromodified in which case you'd need an extra UV/IR cut filter. If the camera is stock, you're all set for some great images and no filter is necessary.

Even with the 130PDS you still face the issue of having no guiding, and you'd want to get to that as soon as possible. I think setting up autoguiding is a sound strategy for now. Its not wasted money even if you do find the mount to struggle with the payload, because you can just use the guiding kit for a possible future mount upgrade. An overloaded but guided mount is still better than an overloaded and unguided mount so there will still be an improvement. For your mount a smaller scope might be the best play, but if the budget can handle a scope or guiding, then go with the guiding for now as guiding is necessary with any scope and mount (within reason, unguided mounts that do well start at like 5k).

I am using the ASI 220MM with my Askar OAG and an 8'' newtonian at 1018mm focal length. The camera is very sensitive and i always have several guide stars in the field of view no matter where the scope is pointing at, i think it would also work nicely for your larger scope.

Is your power tank this one? I was never able to use it with an EQM-35 for the same reasons you are having trouble now. It just cuts off randomly when slewing at full power. At a reduced slew rate it could succeed, but even then not always. I think they put a far too strict battery management system in this thing that cuts off the instant more than 3A is drawn from it, even if for a split second when the slew starts. I think a battery/power station that is rated much higher, like 5A or 10A is necessary for reliable operation. I now have an Ecoflow River 300 which has 2x 3A 13.6v DC sockets and a single 10A 13.6v DC socket, which works well (but of course is much more expensive - no free lunch with batteries).

Not too bad actually, would have believed it to be far more expensive and time consuming. Great to hear that these things have proper support after warranty, would prefer to keep my unit running for many years more.

You can do this measurement at any time, you just get a different result. If you want to know what is the darkest possible sky for your location then obviously choose a night without the Moon and a target towards the zenith. Do note that you get different readings from different parts of the sky, but this is normal. Its also why its kind of pointless to declare a site "bortle 6" if one part of the sky is 7 and another is 5. Exposure time is not so important, just a single subexposure that shows a good amount of stars (a minute or two).

I have found this to be somewhat accurate: https://www.lightpollutionmap.info But for the actual measurement i use ASTAP and its SQM measurement tool. You only have to take a single subexposure, calibrate it, and then run the tool on it. Astap will then make an objective measurement on your sky quality and spit out a number in magnitudes per arc second squared (SQM). I would encourage you to do this actual measurement instead of trusting what some site says, because there can be quite a bit of local variation in conditions depending on how close the nearest light source to you is. Sure is, broadband will take a while but nothing you can do about that. Narrowband with a duoband filter of some kind is also possible and not at all ruined by the light pollution.

Hubble optics also makes fairly light mirrors, on their site some 12" primary mirrors are quoted at 4kg.

What level of light pollution do you have to deal with, and what sort of targets are you most interested in? With your lenses i am assuming you are mostly doing milky way/very wide field imaging, which is mostly broadband and no filter will really help with light pollution. If you wanted to improve emission nebulae within the milky way then you could slot in a narrowband filter of some kind, but not sure that's what you're after.

Funny, reminds me of one of the first times i used Astap, when i forgot to remove my bahtinov mask but it still actually was still able to platesolve the image somehow. I only realized as i saw the first sub come in through NINA and wondered where those horrible spikes came from. Astap+NINA is actually quite trouble free to use once you get the ball rolling. Also regarding flats, you should consider taking them as a part of your standard workflow as soon as possible, they are extremely important for allowing you to fully stretch the image before it breaks down and dust spots come visible. If you used NINA you would have access to the flat wizard, which will just auto expose for an optimal length and take the flats for you. You only need to place a flat panel on the scope for that to work (cheap LED tracing panel for example, or a tablet showing a white screen). But then with flats you also need to take bias/darkflat and dark frames. Keep them in mind for when you get the urge to try something new. Going from a DSLR to a dedicated computer controlled camera is a bit of a leap in terms of complexity, so probably best to focus on a couple of things at a time.

Astap will plateolve an image within a second or two at this field of view, as long as you are within a few degrees of mount to sky error =always, unless you bump the mount or something.

The 585 is a very capable deep sky camera, its just sold under the "planetary camera" flag (in most places) because it is uncooled and the sensor is not as big as some other models. I'd say dont get hung up on that at all, within this kind of budget it is easily the best camera you could buy. You still have hundreds of potential targets that fit on the chip with your 72ED, so its not really limiting your imaging much.

OSC dedicated astronomy cameras will still be significantly better in every aspect, so definitely worth it. For example Canon DSLRs have a red light blocking filter that passes only around 1/4th of Ha compared to dedicated astronomy cameras (or modded DSLRs). So you would be getting Ha at 4x speed compared to DSLRs. Mono with an Ha filter will be around 4 times faster than OSC, because every pixel will be capturing Ha as opposed to every 4th pixel of an OSC camera. So mono + Ha filter will be around 16x the speed of a DSLR and OSC will be around 4x the speed of a DSLR (ignoring other camera specs, in reality the difference is actually a bit larger because DSLRs are more noisy). UV/IR cut filters for astronomy purposes fully pass Ha so you lose none of it when using one, so its not the same kind of filter found on DSLRs. In short: definitely worth it to upgrade from a DSLR.

Passing IR makes proper colour calibration impossible, because more than the visible spectrum was passed. It will also dilute colours in general, because at around 800nm wavelength and above the bayer matrix of most cameras turns fully transparent, meaning the data is monochromatic and all colour information at this wavelength and beyond is lost. There is also the issue of optics. If using a refracting telescope, then passing IR will make stars enormous blobs due to chromatic aberration, because the lenses are not designed to operate on infrared wavelengths. Even with a reflecting telescope there can be issues, such as internal reflections within a coma corrector that cause stars to balloon in size, especially redder stars that are brighter in IR. I have experimented with imaging sans UV/IR cut filter with my newtonian but there were other issues too, such as the flocking of my tube being insufficient at reducing infrared reflections, and the mirror coatings being slightly transparent which caused stray light to pass through the back of the mirror (flats were impossible - complete waste of time). So i think to be safe you really should use the UV/IR cut filter.

Nice one, rich background and all the detail both faint and bright easily seen. Try the Generalized Extreme Studentized Deviate (ESD) rejection algorithm for satellite trails. It works extremely well with stacks that have many images such as this one. The default ESD significance setting of 0.05 could be a bit low, you could try 0.1 if they dont go away but i guarantee they will completely disappear with this rejection algorithm with the right settings.

My strategy for dealing with Windows quirks is to just never connect my mini-pc to the internet - and i never have since i bought it in 2021. No auto updates, no cloud anything, no issues. The only 2 crash/other issues i have had happened when my PC got rained on, but that's understandable.

I would bump up that offset a little bit, with random noise you would almost certainly get 0 value pixels occasionally.

You can quite easily prove yourself wrong by trying to build a go-to platesolving astrophotography rig for under 500£. You will find this to be impossible, and the Seestar is the only viable option (maybe some of the other smart scopes too, not upto date on pricing of other models). This whole discussion is meaningless if we dont take the pricetag into account, and we should as it is one of the most important factors.

There are some pretty damn impressive images on Astrobin taken with a Seestar: https://www.astrobin.com/search/?q="ZWO+Seestar+S50"&d=i&subject=&telescope=&camera=&date_published_min=2011-11-09&date_published_max=2024-03-27&sort=-likes Of course its possible someone has not been honest and some other telescope was used, but i find it hard to believe that people would bother doing that.

Im thinking some of it may be high cloud and background extraction produced some blotches. If you look through your subs youll see if there was something extra. Could be wrong and its just dust. Plenty of dust at this declination.

There is a 254 hour image of M51 on Astrobin :https://www.astrobin.com/7hwtz0/?q=M51&camera= Doesnt quite look like the nebulosity matches, but some of it is definitely the extended halo around M51. Field of view is smaller in that one too, so hard to say for sure. Maybe a bit of high cloud and background noise coupled with actual dust?

You lose only the pixels that are rejected, not the whole image. Usually rejection rates are below 1% of all pixels so not an issue at all. The rejected pixels are replaced by the median value of that pixel from the stack so there will be no evidence left that there ever was a satellite trail in the first place.