ONIKKINEN

I had, and still somewhat have, significant cone error in my 8" newt and field rotation on a target at 74 degrees in DEC was definitely an issue. Best advice i can think of is to look into fixing cone error if you dont have the sensor area to spare to crop the corners out.

Mount prices have varied a lot in the past few years due to component shortages and probably other things so i wouldn't try to build a general price increase model based on mounts alone, but from what i can gather it seems that prices have generally gone up by about 10-20% depending on the kit in question. I dont really see this trend decreasing that much, if at all and dont think much of it. If i couldn't afford an item before price hikes, the 20% increase means nothing to me. If i could barely afford the item before, saving up for the extra 20% is probably not that big of a stretch. My view on whats expensive and whats not has become really deranged since starting astrophotography so maybe that's why i dont think the price situation is a big deal right now.

The most frustrating thing has to be sudden shift in weather from clear to cloudy. I do mobile astronomy only so every time i want to set up my stuff takes at least 90 minutes until the camera or eyepiece is in place and doing work. I try to look at all the different weather services out there but lets be honest, none of them hit their mark every time. The times when i go out and expect a clear night only for the clouds to roll in AFTER i have gotten setup destroys me inside every time. Its really demoralizing and makes me feel like a complete clown. 90 minutes to set up, wait maybe 30-60min for the weather situation to become more clear and then tear down the stuff and head home without doing anything 🤮. I have gotten much better at judging weather in the past 2 years though and this problem gets smaller and smaller as time goes on. For my imaging they have never been a problem since sigma clipping removes all outliers even if there are a lot of them across the entire night. For visual its a nice curiosity if anything.

Something is a bit weird here, can you clarify a few things? Did you use flats when stacking? If so, did you also take bias (or dark flat) and dark frames? Also, what camera, what scope etc? Superstretched version for diagnostic purposes below: Its difficult to tell for sure what is going on since there are so many different camera orientations going on at the same time, but to me it looks like you have quite severe overcorrection of flats going on (middle is darkest, opposite of what it should be). Could also be from dew/frost on a secondary mirror or maybe in the center of a refractor lens (that im not so sure about) if you did not take flats at all. There is also a weird looking diffraction spike on some stars that appears to not be a typical newtonian 4-prong one but just a 1 or 2 sided spike? Not sure what to make of it.

I would skip the 5 class mounts and go straight to an EQ6 class one if you are considering spending that much money in total. Youll thank yourself later and leave some breathing room for growing the setup. I have an AZ-EQ6 with an 8" newtonian and the mount is not overkill at all even though im at less than half its rated capacity.

Things like this are why i wont be upgrading until win10 support ends, and probably not soon after that either. I hate it when windows just decides to change a feature without asking! Can you remove auto updates in win11? I have done so with registry edits in my win10.

The mount it is then. No contest on this at all in my opinion. You cant really overmount a scope so getting the best mount you can with your budget would be the best choice. You can keep using your current setup with the better mount and get somewhat sharper images due to much better guiding. Does depend on your total budget a bit though, if you have enough to spare you could buy a mount + something else, but just guessing since you did not mention.

Periodic error is there regardless of payload weight, could it be that you are just now noticing it?

Did a quick process and got something that looks similar to yours so i dont think you missed anything: I feel like i want to stretch it more, but things get noisy quite fast with more stretching so this one probably needs more time under the stars to show up more of the dark dust. Dark nebula processing is quite tricky so i could be missing something too of course 😃.

The focal point does not extend far enough outside the focuser to reach focus with a DSLR. Youll need to either push the focal point outwards by moving the primary mirror up the tube, use a camera with a shallower flange distance like a mirrorless camera or a planetary camera, or use a barlow lens to push the focal point far enough. With the barlow you will have some other issues but thats probably the easiest method.

Binoculars are hard to beat in terms of convenience, if that qualifies as a scope. Lots of things to see with 7x50 binos if skies are dark enough!

For imaging purposes most mounts are almost self aligning, with only polar alignment requiring manual work (apart from the Avalon). Polar alignment takes 2 minutes to get within an arcminute and the star alignment thing later on is not necessary at all. Both require there to be some kind of plate solver in play but for imaging purposes i think most people do have that capability and this way its mostly on autopilot.

Not seen this one before, very nice shot. Looks to me like its quite rich in Ha so am interested in seeing how adding that improves it more.

Thank you Vlaiv, i have learned much from your expertise! Actually not just much, perhaps most of what i know today 😅. I think i would still be drizzling DSLR images with 7'' FWHM stars if i had not found this place and the experts in it...

Abell 1656 is a rich cluster of galaxies with a mean distance of 336 million light years from us here on Earth and contains as many as a thousand galaxies. In this image i can confidently say that at least a few hundred individual galaxies can be seen, some better than other of course. The cluster contains mostly photographically uninteresting elliptical galaxies which lack star formation and so have a uniform warm white colour to them due to the lack of young hot blue stars. There are some spiral galaxies and irregular galaxies too of course, but none have cleared the noise level yet to be well resolved with their features (perhaps with the exception of NGC4921). Everywhere i look in the image i see a faint background galaxy, its really mind boggling to be honest at just how many stars could be in this image and how many of those could have rocky planets and how many of those have someone pointing their version of a newtonian reflector towards us at this moment? I dont think its unreasonable to say that the number is not 0. I could daydream about stuff like this forever, which is why i wanted to shoot this target that, lets be honest, is not the most photographically interesting one. And the (silly) annotated version: Shot with my stuff which is the VX8, RisingCam IMX571 OSC camera and the AZ-EQ6. Shot over 4 nights in total, of which the last one i unfortunately scrapped completely due to seeing, so 3 nights and 9h stacked for this shot. Was aiming for a much longer integration and i dont think its quite "there" yet but the season has ended, so this will have to do for now. I shot from a bortle 4 zone using only 60s exposures, just to prove to myself that the process of taking short subs and getting faint stuff out of them works, and i can say that it does since the subs themselves only had as few as 30 electrons of median background signal! Also, it was windy as hell so not much sense taking longer subs from that sense too. Processing tools used: SiriL, GraXpert and photoshop. After calibration i split the subs to their individual colour filter channels without debayering and vetted those with the plot drawing function in siril. I used simple measurements to make the calls, like: FWHM, roundness, background level etc to remove outliers. In the end i stacked somewhere around 500 red and 550 blue subs and more than 1000 green subs to recomposite back into a colour image, but now with improved SNR and a more reasonable sampling rate of 1.84'' per pixel compared to not bothering with splitting. The red channel ended up lacking since i had a bit of an oopsie with an uncovered rear of my scope and a red LED on the mount blasting light directly inside the tube for a while on my first night, but since i split the data i was left with working blue and green channels for that, so not a huge loss. Comments and feedback welcome!

The tidal tail was starting to form in an image i took a while back with just 2h of 60s OSC subs containing only 40 electrons of median signal in the green channel: Not anywhere close to being drawn out to a presentable image of course but i did notice it was there so i think you could get away with short subs as well as long ones. Just takes a long integration to draw it out from the sea of noise i think. Not sure how to estimate how long but judging from my image around 10-20h would probably form the tidal tail nicely with similar quality short subs.

This would be on the top of my wish list as well. Would be interesting to shoot the same patch of the sky as hubble did to do a direct comparison. Some of the hubble deep field objects are redshifted to outside what hubble was meant to image and i think JWST would be right at home for those faint fuzzies.

I have mixed 30s and 60s subs and also 2 different gains in a stack and i dont think there were any issues. Normalization did its thing and less than 1% was clipped in the end with sigma clipping, so i dont think in that case there were any issues.

Actually i think thats common, at least when my scope was out of collimation (still is sometimes 😅). One side of the image was always better or less apparently bad than the other. If all of the field of view is bad then the scope would be nowhere near collimation, like my first scope, an Astromaster 130 was.

If you didn't mention that it was a refractor i would have assumed the picture is from an out of collimation newtonian. Looks very similar to that. Could the scope be out of collimation? Dont know how common that is with good scopes like a takahashi though.

This blotchy look is because of running the tool, not somethig that exists in the flats themselves. Your flats are fine, they just dont match your lights because of mechanical problems, and using someome elses flats is guaranteed to be worse.

I dont recommend the smaller Celestron power pack (the 7.2 amp one). It can only supply power via 12v DC or the USB port, so no accessories like dew heaters off USB power at the same time. It also has some "smart" features like shutting off power if power consumption is too low, or too high. I found that it was not in fact enough to run an equatorial mount and during go-to it shut off instantly so its not really useful for much. The 12v output is also not regulated, or at least not that well, and will drop below 12v before power runs out. Build quality is also poor with the plastic covers just breaking off after one use. Terrible product and hilariously expensive! The jackery sounds reasonable and future proof however. I have a similar product from another brand (ecoflow river 300) and its been flawless.

I liked the second one best, the one with the lifted background. I think in your third pic the contrast inside the galaxy went a bit too far and it looks a bit out of place compared to the rest of the image. M51 looks maybe a bit too high in magenta, almost like you imaged without an IR cut window/filter or H-alpha blending went wrong or something. Minor gripe though since the picture looks great anyway.

Oh my, i can imagine my heart skipping a few beats after a fumble like that, especially since these tubes are not easily replaceable. I think it shows the tube is plenty strong enough if it handles an extra hole like that and still shows no flexure, so you could call it an improvised stability test. 😉 Looks like a useful hole for ventilation and maybe some light mirror dusting though, so not a disaster i hope!

I notice a few things with the images and it does seem that flats dont work quite as they should here, but the blotchy result from siril background extraction always looks like that when my flats have not worked perfectly so that is more of a symptom that only is visible after running the tool rather than the actual issue. The tool really doesn't like mechanically failed flats and so the background remains flawed. I noticed that you have rotation between the single sub and the stacked image. Was this taken on 2 different nights so with different camera orientations? Or did you remove the camera during shooting? In any case, each time you remove the camera you need separate flats for that specific rotation and the previous ones will not work if you remove the camera and put it back. First issue with the flats is that they are rather dark at 3115 ADU out of 16384 (14 bit camera). Would probably be better to either expose a bit longer or use a brighter light source for the flats. Not sure how much this effects all the other things here but i would look at bringing the flats exposure to around 50% of the histogram first. To my eye it looks like you may have some kind of small motion in your optics between the flats and the lights, which is not a shocking surprise given you are imaging with a newtonian where many parts can move and so ruin flats. Its most apparent in the worm looking shadow on the top of your flats: The same spot in your calibrated sub clearly shows that the shadow is still there and has not been removed by the flats: It could be some hair or fiber that has moved on its own during imaging, but if not it tells of more issues. To me it tells that there must have been movement somewhere in your imaging train between taking the lights and the flats. That could be the primary mirror moving in its cell, the cell itself being weak, the tube itself bending, the focuser drooping (quite likely will, if stock focuser), or the camera being rotated in the focuser. Dont know how that last thing could happen by accident, other than if you removed the camera between shooting the lights and flats but in that case not really by accident. The resulting stacked image shows a dark center half-circle (purple:darkest, red:brightest) and a nonlinear gradient. I made the fine artwork below with paint and a screenshot in the rainbow false colour rendering mode and histogram stretch mode in siril: This kind of error could be from light leaks, mechanically failed flats or both. Or inner reflections. Anything goes really. You do mention that things are flocked and light leaks proofed but i cant help but think that it still looks like light leaks are getting in somehow. Have you blocked the DSLR viewfinder? That would be light leak source number 1, leading stray light directly to the sensor. If flats had worked there would not be this kind of nonlinear circle-y look to the center and it would be edge to edge linear (like the line i drew diagonally). Could be some overcorrection at play as well since the center is slightly darker than maybe it should, but not sure how to go about fixing that. Your focuser probably has some side to side travel in it when you rack the focuser in and out, which is why you should collimate in the focus position. Racking the focuser in and out will change the collimation in the case if this happens and that is why you see the effect change in different positions. Try putting a laser into your focuser and rack it in and out, i wouldn't be surprised if you see the dot move a bit on the primary mirror. So my thoughts: Mechanical issues somewhere preventing accurate flats from being taken, if they were taken for each session and before touching the camera. I would look at the focuser first. I have mostly removed issues like this with my newtonian with an upgraded focuser and looking at reinforcing my tube so that there is less flexure. To try and band-aid fix this since you cant really retake flats now, you can try to run background exctraction per sub in siril. It might leave a cleaner background than running the tool in the stacked image. You can also then see which subs had functioning flats and which did not, and could remove the ones where the background is messy after the extraction. If you are unsure how to do this, calibrate your images like you normally would and open the sequence of the calibrated subs. Then open the background extraction tool and set it to 1st degree order, 20 samples per line and 1.0 tolerance and generate the samplers. Then just click the Apply to sequence and siril will remove the background from all of your subs this way. Then you can browse the file list and see if you spot some of them being out of line (probably wise to look at first and last sub and compare) and remove those if you want a cleaner background. I think the image you have here is workable though and it wouldn't be that difficult to clean up later in Photoshop or gimp or whatever you use. I wrote quite a ramble above, i hope there is at least half a sentence that makes sense somewhere in there 😃.