ONIKKINEN

Interesting, yet another imaging misconseption of mine you have pointed out😄. How big of a loss (or how much less the improvement) would resampling in post do? In SIRIL there are a few options like bilinear, bicubic, lanczos, pixel area relation etc. I would love to pretend i can see a difference between them but i dont. If there is a big difference, would it be better then to capture binned by setting the driver to bin2? I can see straight away from HFR readings that the night is not good enough for native resolution and lose nothing of value by binning on camera.

Not a ZWO product, but still an IMX 571 sensor camera (by rising cam, manufactured by touptek). I always bin 2x2 which is just a 50% resampling in post as far as i have understood and i perceive no lost colour data. Read noise gets "read" from each pixel regardless if your capture software captures native or bin x whatever resolution. There is no need to do binning during capture with CMOS other than reducing filesize, you can do this in post in whatever software you use to post process.

Here is what i came up with from the linear file. I don't think i improved it, its just different. In the linear phase i do background extraction and colour calibration but looks like these were already well enough done on the stretched stack. Colour calibration is really tricky and i almost entirely rely on SIRIL photometry to do it for me. In this case SIRIL only found a handful of stars, whereas i usually use hundreds - that's the only 8 minutes here that does it. Still amazed how stars are mostly round untracked!

Untracked and 8 minutes? Looks great, probably better than my tracked M42 which i pretend never happened. I don't think i pulled more out of it. Although i will say the TIFF in your post looks already stretched as the linear mode already is very visible (stacked files are usually almost entirely black), is it straight out of the stacker? I did: Background extraction in SIRIL (minor effect), some photoshop masked saturation, camera raw adjustments and denoising.

Thank you! I am hesitant to try and "fix" the issue since there are so many possible surfaces to reflect from. All coated of course, but still possible. 3 glass elements in the coma corrector, both the telescope side and camera side are visibly curved (0.95x TS maxfield corrector), UV/IR cut filter, AR-coated sensor window and of course the sensor surface itself. I can probably improve the process of removing it in post if i practice, so its only a critical issue if it obstructs the actual target itself. Here is a picture showing my CC in the focus position, it does not obstruct and is sufficiently covered to not have really any "direct" reflections. (dew shield on while imaging also). The comacorrector is open only to the opposite side where there are no bright stars. Dew in the sensor would be bad news, but i don't think that's the case ( i hope not). The sensor is sealed with a desiccant tube thingy in there and the number of stars/median ADU/HFR readings from NINA i use to determine sub quality show no jumps. If there were jumps, the subs were scrapped. But very fine mist not big enough to notice? Could be, ill have to check the desiccant if its saturated. I am not so sure at all it was the top left star in the image. It could also be 3 stars just below the image that are also quite bright. In fact it probably is, since i have not seen on-axis stars produce something like this before. I have seen something like these reflections during go-tos to bright stars for focus. The first go-to is always a couple of degrees off and can show some reflections, but once centered they disappear. The Moon obviously also causes these when anywhere in the general direction, but not rainbow coloured.

Thanks Geoff. I noticed this technology gap while browsing astrobin for various targets and it looks like comparing today's images to even a few years back is a very uneven playing field. I wonder how astrophotography looks like 10 years from now if the same improvements keep on coming. 23 hours is a LOT of exposure for a single target, not sure i have 23 hours in total 😅.

It adds some flair for sure. What im not sure if its from the HD-something star in the image or Kappa Draconis a few degrees to the bottom that caused this. Havent seen one like this before so there must be a tight spot where it can occur at a specific off angle.

I think i actually prefer the non-altered background version. Actually i definitely prefer it, so here it is. Trying to remove the rainbow reflection is probably what killed the background in the first round.

Thanks, although more southern photographers might have to wait a few months for a better opportunity. NINAs sky atlas told me about it, otherwise i doubt i would have just stumbled upon it. At 20 arcmin should be shootable for many kinds of telescopes!

I don't have pixinsight, but this sounds bizarre. Elliptical galaxies being round featureless mostly single coloured blobs are about as far away from M33 as possible when it comes to galaxies. Maybe try just "normal" photometric colour calibration (if there is one in PI?). SCNR also shouldn't be necessary after a good photometric colour calibration so something is wrong.

668 x 30s - 5h34min NGC 4236 is a low surface brightness (magnitude 24/arcsec according to stellarium) barred spiral galaxy in the constellation of Draco close to the naked eye star Kappa Draconis. Plenty of PGC and other distant galaxies everywhere in the field of view. Haven't really seen this one before, and it doesn't seem to be a very popular target, so why not go for it myself? On acquisition: Shot with the gear in the signature: OOUK VX8, RisingCam IMX571 OSC, EQM-35, mini-pc etc. from a Bortle 6-ish area. Shot on 2 different nights. On the first night conditions were really not great, bad seeing and very humid but moonless. Second night was also moonless but very good transparency and seeing, in fact i don't think i have seen better yet. Contemplating whether i should scrap the first night and add more of the good stuff, well maybe one day since this target never sets low enough in the sky to be troublesome. Guiding was great (RA only), as it is for this patch of the sky for me. No subs over 1 arcsec RMS stacked, and i believe the average could be as low as 0.7. Some subs on the better night were as good as 0.3 arcsec RMS for the duration of the exposure, safe to say i never expected to see numbers like this from the mount. Perversly as the target gets higher in the sky guiding gets worse, since the tube is more vertical and my mount really doesn't like that, so most of this is just after the meridian on the north side. left side of the shot has some tilt/spacing/collimation issues. Not sure at all which one or all of them is the cause, working on that. Processing in: DSS - SIRIL - PS. Starless and starlayer stuff with StarXterminator, also some optical aberration surgery since the mag 5.8 star left a rainbow reflection in the bottom left corner of the shot. The background is quite "nuked" and remains a bit spotty/noisy, but it works for now. I will probably return to this target one day, i feel like 5h34min is not quite enough for this target and there is probably more to see. Feel free to comment/advice if you want, still getting to grips with, well everything in astrophotography.

yes, but the other innards need good lubrication. Like in the pic (EQM35 DEC axis)

My EQM35 had very viscous and sticky lube in it, presumably to hide backlash and mechanical tolerances in the design. Hope they dont use the same stuff in the better mounts as it has no place in a precision instrument. I would recommend relubrication for everyone who is even a little bit DIY oriented.

Sounds like a backfocus issue. Is the image at its best in near or far focus? If in near, add spacers. If in far, youre out of luck because you cant really remove spacers if there are none. You should have the same backfocus distance to the 533 as the flange distance is in rhe camera your sigma is made for.

Cooling is just a minor part of the package with new cameras, especially the 2600MC and others with the same Sony IMX571 sensor. For starters, you can expect to almost double your cameras quantum efficiency = the amount of light that hits the sensor and actually gets turned into a value in a pixel. So, a 30s exposure will gather 60s worth of light compared to the 600D. Noise will just disappear compared to the old Canon DSLRs. Shooting with my Rising Cam branded IMX571 feels like cheat codes after using my old 550D. I think a 10s exposure is about as useful now as a 30s exposure used to be, or maybe even better. I am never going to touch the 550D again. I would say its impossible to not notice the difference. Its not as plug and play as DSLRs, so if thats why you gave up with the 183mm and 183mc, then expect to have the same convenience issues with any model. But the image quality will be objectively better.

Agree with the above about colours, but still a great capture! Face on spirals are really photogenic. I try not to not call a shot finished after processing because sometimes i get "colourblind" by looking at the same image for too long. I just save the image and do something else/browse other images. Next day i see something i should have done differently and re-do processing. The too green/too purple problem goes away with this for me.

Pretty damn impressive for 8 subs.

What in the world requires these kinds of artificial suns in the middle of nowhere pointing horizontally??

Just saw very frosty conditions at -5c and 95% humidity. Every outside surface was covered in a thick frost layer, but the inside was perfect. Nothing on the flock or anywhere inside the tube, so nothing to worry about.

Answering my own question: Perhaps works in theory but annoying to setup. Quality is not that much better since i tend to have higher frequency wobbles in my mount. Good idea on paper, not so much in practice.

Good to know. I expect to shim it anyway to properly center the focuser on the axis. My tube is slightly non-round so i have shimmed my current focuser with washers on one side to center the focuser on the secondary without having to adjust the spider to be unsymmetrically offset.

Anything above 100 will be ideal judging from the graphs, but much higher than 100 is maybe not that useful. You can use whatever gain above 100 as long as you wont saturate stars, but stars are easy to saturate so maybe dial it down to 100, or reduce exposuretime.

First frost of the season. Welcome back, cold still winter nights!

Just ordered one. Cant seem to find much negative experiences online, must be for a reason. Question for owners: Versabase. Whats the function of that? Adjustable base?

Ah, i should have said that it does come with 2 adapters, a 2inch and a 1.25 inch one! Just not the 16.5mm and somesuch adapters for use with correctors to get backfocus correct out the box. I like the word bomb proof and think it fits the case well. Im sure the carrying case could be catapulted off a cliff and survive.