ONIKKINEN

Interesting, never thought to doubt it when i first saw the video a while back when all this was announced. Just kind of thought these guys must know what they are doing but it doesn't look great here wit the examples.

I should mention that i found this off google image search and its not something i have made myself. Should you google 533MC sensor analysis you find a number of results, some of which have slightly different values so for the purposes of creating a spread sheet you should probably take an average of the found measurements instead of one of them at face value (although the differences are very small). I have done the sharpcap analysis on all of my cameras a few times and the measurements vary a little bit. Both vary between different runs of the tool and between the measured and camera manufacturer stated amount i mean.

Here is a sharpcap sensor analysis result sheet from the 533MC: Should contain all the details one needs to figure out what number to put where in the read noise swamping formula. So at Gain 200 we have 1.42 read noise and 0.32 e/ADU rate (ADU=camera measured value, in this case 14-bit). Offset was already defined as 50 which is 500 ADU or 2000 in 16-bit. So for a read noise swamp factor of 5 we get this: 1.42*5 = 7.1 which when squared comes out to 50.41e. 50.41e divided by the e/ADU conversion rate of 0.32 comes out to 157.5 in 14-bit values. Multiply by 4 to get 630 in 16-bit values which is what your software using the camera will report. This is the number you are looking for to have on top of your offset. Your offset being 2000 in 16-bit means @BrendanC you are looking for a number of 2630 given by APT/NINA/whatever else when out in the field in order to swamp read noise x5 at gain 200. I think in your shoes i would rather shoot at gain 100 as the drop in read noise is really not that much. Unless you are scraping the barrel so to speak in terms of mount performance. With gain 100 we get: 1.63*5=8.15 squared to 66.42e, so only 16 electrons more compared to gain 200 but you get triple the full well. In the case of gain 100 you are looking for a number of 2260 reported by the capture software to swamp read noise x5.

@BrendanCand others, i think this part was skipped in the above calculations. The 533MC is a 14-bit camera but as far as i know every software will report measured values in 16-bit. The output value must be converted back to the original to have meaningful e/ADU conversion rates and other measurements regarding noise amd whatnot (divide by 4). Offset of 50 equals 500 in 14-bit values (the only thing the camera cares about) and becomes 2000 when converted to a 16-bit number. The above calculations come out as 237e if converted to 14-bit which sounds a lot more reasonable than 950e.

You want to have the longest integration possible, but only have the best subs in it so you have to compromise. Look at the average quality of subs and deselect the ones that are clearly worse than the rest, but definitely dont reject 90% of the stuff. If you have a fair bit of variation in the data you should use some kind of weighting for the subs that are stacked, so that the worse ones have a lesser effect on the stack as the good ones. That way you can stack almost all of the data except for the clearly wind/high cloud/mount issue stricken ones. I have seen the number 6 floated around for the minimum number of images that rejection algorithms can work with so less than this might result in satellite trails not being removed.

Doesn't look like stacking the 2 would have any effect because the L3 has a much wider pass than the L-enhance. You could stack the L-enhance + red or green filter to let trough only OIII or Ha instead of both. This would tighten the stars a fair bit, but of course youre only letting one of the bands through so it will be more time consuming to get an HaOIII image out.

Last night was clear with some high cloud, was imaging there. Even though it was technically a full Moon night the Moon was only above the horizon for about an hour and even then so low in the sky that the conditions were still pretty good (B5 probably). Saturday was clear too! I know the forecast said something else but that's just how it is. Imaged something else than this though because i am a fool and have started another long project. Hopefully dont have to spend 35 hours on this one .

f/12 with the tiny 2 micron pixels of the 678MC is going to be a really bad time with DSO imaging. Not saying its impossible, but we are getting there especially since you are not guiding. If you wanted to try and make this work you would need to guide and expose for probably at least 5 minutes (as long as possible really) for the images to be something other than mostly noise and for stars to start to be visible beyond the noise. Really the sanest approach to starting DSO imaging with your mount/camera is with another scope. Probably some short focal length refractor which will be more forgiving with your short exposures and lack of guiding. The camera is still not optimal and maybe you would have better luck with something else, i think you may have pretty much one of the worst combinations of kit for DSO imaging with all this, sorry!

Looks very clean, these should work well.

The main sensor looks pretty large, maybe a full frame. If so its going to be very expensive and most scopes wont be able to take it. But if this is a range of new products then maybe there could be more wallet friendly options with 21-28mm diagonal sensors? Seems like a useful idea, one less imaging train trinket to worry about.

I have a steeltrack on my newtonian too and it does leak a tiny little bit around the drawtube and around the base. The base is easy to seal with some black duct tape or whatever you have on hand. Other than that have found it to be not an issue when shooting lights so have done nothing too drastic about it. My scope is well flocked though so any light that creeps through the focuser to the inside of the tube mostly gets absorbed and not reflected back to the imaging train.

Just went trough the files, and yes you have significant light leaks that make calibration probably impossible, even with the new files. First your old dark which is completely ruined by the rear leak, see a rainbow rendered stretch (blues are dark and reds are bright, the light leak is clearly skirting around the primary mirror from the rear of the scope): But your new one is not great either: Clear gradient, which shouldn't be there. Median values in the new dark are around 460 when they should be very close to the offset value of 10 which with your camera results in 400 in 16-bit values so you still have almost 60 electrons of light leak per pixel here when just one will make calibration difficult! In short, light leaks still reign supreme and to fight that i recommend you take the camera off the scope and shoot a library of darks and darkflats in complete darkness. The light leak issue still needs to be solved because they will imprint the weird gradient onto the light frames themselves, which may result in funny looking flats calibration even if the darks were taken in darkness. On the exposure length and histogram, i think yours are just fine. Unnecessarily long exposures though, there is no need to expose for 4 seconds with your camera but of course also no downside other than it will take a while to capture the flats. Your flats histogram looks like this: Mine looks like this with a triband narrowband filter: Mine calibrate the image just fine even though 1 of the peaks is nowhere near the center. Basically dont worry about the histogram, as long as nothing is clipped to black or white you will have good flats calibration. If you want to nitpick the flat you could push the histogram a little bit further so that all the peaks are centered around the midpoint but i dont think there is a point for doing this other than peace of mind. In short, round 2: i wouldn't worry about the histogram at all, seems good to me. I think a lot of the flats related talk found online relates specifically to older cameras that can have nonlinear sensor responses to light and/or exposure length and so need to take some specific histogram and a long enough exposure to make the flats work (294 might be one of them). For the new Sony sensors (533,571, the fullframe version + others) you just dont need to do any tricks since the sensors are 99% linear and have no weird instability issues with any exposure lengths. I take my flats at 0.05, 0.2, or 1s depending on what gain and filter i used and never had any weird calibration issues.

I am assuming you have taken the flats after the imaging session, without touching anything on the scope such as removing the camera etc? If so, need to do some educated guesswork. Post a flat, a light frame that matches that flat, a dark frame and a bias/darkflat frame in .fits format as an attachment so the raw data can be seen for possible clues. I am guessing it will have something to do with light leaks if all the calibration frames are otherwise sound. The rear of the tube will let in light unless you have blocked it somehow for example.

@vlaiv is wise and has given good advice. I f i were you i would stick with the 8'' newtonian and maybe look into a better quality coma corrector if you happen to have one of the cheaper ones (Baader, Maxfield 0.95, Skywatcher 0.9 etc) as they reduce the maximum sharpness you will get out of the scope. Vlaiv's advice was difficult to swallow the first half a dozen times i read it, but time and time again it has been proven to be right at least in my conditions. 1.5'' resolution is already a very demanding target and more than half of the time the skies will just not allow it no matter how much quality glass is in the scope. In my typical seeing a resolution of 2''/pixel would be ideal, with 1.5'' being a nice good seeing night target. 1'' however i am not sure if i have ever had the conditions to reach. Definitely, makes all the difference. This wont give you sharpness any more than your DSLRs, but it will improve signal to noise ratio drastically allowing you to get a much better image in the same amount of time.

Nice and tight diffraction spikes, works really well with open clusters.

Thanks, i am surprised how quickly the image took form even under the Moon that night. I think i could get used to this narrowband nebula business.

I used it for a while and have 2 major gripes with the design (mine was TS branded). First is that it has issues with internal reflections if a bright star is within a few degrees just outside the field of view. See below for examples (the coma cluster one was particularly difficult to remove, almost ruined the shot): There was another case where i was shooting a comet but cant find the data now. It was garbage so might have deleted it but it had a reflection across the center of the image from Pollux a couple of degrees outside the FOV. The second is that it doesn't do a very good job as a coma corrector. Never saw good sharpness across the frame no matter how much backfocus searching i tried. In order to get decent stars across the entire frame i had to focus using a star in the outer third of the field of view. That is obviously a compromise as it means the center stars are not at their best focus. To be fair it wasn't awful, but still there are better options at similar prices (such as the 1.0x GPU) so lets say i do not recommend this one. I upgraded to a TeleVue Paracorr and yes i know its literally twice the price so not a fair comparison but my star sizes measured in arc seconds improved by 20-30% compared to the Maxfield. On axis performance improved even more, but since i still need to focus with a non-center star the center sharpness has limited benefits. ***Forgot to mention that my scope is an f/4.4 one, i have seen mentions online that the corrector does a much better job for f/5 primary mirrors. Apparently something to do with spherical aberrations being introduced with faster mirrors.

2 panel mosaic with 2 hours in each taken last Saturday under significant Moonlight. Was a very windy night but i dont think its too apparent at this resolution of around 2''/pixel. The bubble itself is slightly less red than the surroundings, meaning there is probably some OIII signal in there, but a red blob is all i could manage this time. Another maybe in the target list for things to return to.

Midjourney is crazy, been following its rise with great interest. I can see some real world changes in some creative fields with the rise of image generating AI. Think of video game development for instance. The AI could spit out an endless barrage of hallucinated images in the same timescale as an artist comes up with one or two concepts.

Thanks, my favourite too. I like the texture surrounding the mountain range to the right, something i dont think i have seen in my own captures before.

RGB lunar is tricky. It takes good colorubalance to be able to saturate the image so that any single hue doesn't overpower the image. Sometimes i do Registax auto RGB first, saturate bit by bit and then tweak manually later when the colours start to appear. It takes an insane amount of saturation boosting to get anything visible, im talking like +20 saturation in PS 10 separate times or something like that. Trying to go +80 saturation at one move will nuke the image for sure. I dont think i use any capture white balance, but really i have not thought about it and just let Sharpcap take the wheel. the CameraSettings.txt file that Sharpcap writes says this: White Bal (B)=99 White Bal (R)=62 Brightness=3 So maybe there is some kind of balance? Really should know the answer, but dont. Colour is a funny thing, i also thought the first batch looked nice on my main monitor but on my secondary one and to a lesser extent on my phone i am seeing a little bit too much olive green overpowering the image. It is subtle but its there, the second batch is without the hue but then i might have gone too far in trying to remove it and turned things too purple/blue.

2 panel mosaic with around 90 minutes in each of them, shot under an almost full Moon last Sunday with an 8'' newtonian, RisingCam IMX571 OSC and the Antlia Triband RGB Ultra filter. Mosaicing in APP, processing mostly in Photoshop. The filter picked up loads of Ha, but not much other than noise for green and blue (little bit of something in green, some OIII probably). Still happy with how much stuff it picked up in such a short time under an intrusive Moon. Might need to expand the mosaic and invest more time into this one day. This was at the northern meridian and still not too low in the sky, so plenty of opportunities round the year to maybe make that happen. Big maybe, lots of targets in the target list and looks like its not going to get any shorter.

Looks like the mount never actully slewed all the way during the meridian flip. DEC 85 and RA 1h57m is on the wrong side of Polaris as the intended target, but why exactly the mount wouldnt slew again is beyond me. Looks like some kind of setting that prevents syncing close to the poles (but then again the mount is not suppposed to be there). Could the scope hit the tripod when pointed towards the zenith? That way the motors would start skipping steps leading the mount to think it has moved the scope when in reality it was stuck against the tripod for half of the slew, which could place the scope close to the pole where the "unable to sync" thing comes out.

Hello and welcome to SGL, For a newtonian i will recommend an OAG over a guide scope any day of the week because the primary mirror itself can move a little bit during the night and the tube itself could slightly deform under gravity in different positions. If guiding with a guidescope, the guider is unaware of these movements and you can have bad looking frames while guiding reports everything is ok. OAG guiding fixes this since whatever movement happens anywhere between the OAG and the primary mirror will affect guiding also and be corrected. For OAGs you have some choices, but most of these are convenience and sensor size related. Cheapest ones have 8x8 prisms and no guide camera focuser, more expensive ones have slightly larger prisms and integrated focusers for the guidecam. I have an Askar OAG in my 8'' newtonian which i have found to be very nice. As for a guidecam, just a simple ASI120MM will do the trick almost all of the time. If you plan to place narrowband filters before the OAG (such as at the end of the comacorrector) then a 220MM will be a better choice.

Fresh eyes reveal that these look a little bit too green on my second monitor and phone, so here are versions with slightly different colours: