Xiga

Thanks Alan. I've done so little actual observing since I took up AP a couple of years ago - I really need to get back into it!

Thanks Rick. There's tonnes of Oiii in the NAN so go for it 😎

Thanks David. I wanted to see how far I could push the brightness range, so I pushed it quite hard.

I thought i'd revisit this one, as i was never truly sure abut the processing originally. So with this one, i sought to improve the stars (they're a big improvement) but also bring out more of the dark nebulosity. Did i go too far though?! Looking at it again today i think i may have. 🤔 Details: Ha: 7 x 480s, 6 x 1200, 13 x 1200 (a little over 7 Hrs) OIII: 9 x 1200s (3 Hrs) RGB (with IDAS-D1 filter): 20 x 60s The usual Flats & Bias, stacked in APP and processed in PS. Gear used: Nikon D5300 (modded); SW 80ED (522mm FL); HEQ5-Pro; SGPro and PHD2. The original version can be seen on the Astrobin link. C&C welcome and clear skies folks! ps - At the moment this is still at 100%, but i'll probably end up down-sampling it to about 50%. I don't think it can hold up to 100% tbh. Edit - Here's the new, now much more toned-down, version. It's a clear improvement, so i'll have to keep reminding myself not to try and go for big & bright, when subdued nearly always ends up looking better! Original, nasty over-bright version: https://astrob.in/346428/C/

Absolutely amazing. One of my favourite objects, and your son has nailed it. Well done indeed! He obviously has a good teacher, so well done to you too André! Yes, but on the plus side... 😂

Ok one last fiddle. I decided to tweak the colours slightly, as i thought it was looking a bit too Ginger and not Gold enough. I also dropped the black slider in the Reds in selective colors to lighten and expand the Ha nebulosity a bit more. While i was at it, i also decided to enhance the contrast a bit too (with a High Pass Filter) to try and ease the slightly soft look. I'I also went with a lesser crop too. Hopefully it amounts to an improvement and i didn't go too far?!

Thanks Rodd. All fair points, and ones I did consider at the time. I'll try to explain my half-baked thinkings 😅 The new version has had a fair amount of colour NR (DSLR NB data really needs it) but you'd be surprised how little Lum NR it's had. The lower stretch meant the the image was just nowhere near as noisy as the original. Of course, as you have rightly said, this means a lot less of the Ha nebulosity is visible in the final image. This was purely a judgement call, i think I really needed a cooled mono camera to push the data further. I think I normally tend to over-stretch my data, so I'm going to try and resist more going forward. I probably over-cropped it too. The data probably can't support a 100% crop too now that I think about it. That might be contributing to the slightly soft/smooth appearance? As for the stars, I only did a small amount of star reduction. I think what you're seeing is just the effects of the lower stretch, which affected everything, including the stars. The issue of green in astro images is one i totally agree with you on, for RGB images. It's taken me a while to realise it, but I now really like leaving a little in there on NB images. Maybe it's because I'm only using 2 filters instead of 3, but I've found that if I nix all of the green then the image tends to look a bit too flat and lifeless to my tastes. But to each their own of course! 😀

Thanks mate, very kind of you to say ☺️ As for doing long exposures, I don't think it's down to anything special that I do tbh. I just read up on guiding and started doing it, lol. I have to set up from scratch (and tear down) each time I image, which is a pain I have to say! And the mount has had a motherboard replacement too. But aside from that I'm very happy with it. I've done the belt mod, but even before that I found it guided well. My only gripe with it is the payload capacity, as I'd probably need something beefier if I wanted to upgrade to a bigger scope.

Thanks Carole. You're too kind. Either that or it's time for an eye test! 😋

Hi guys First things first, apologies for posting this one out of season. A combination of no astro dark, crappy weather, and being busy at work has meant that there's no imaging getting done at all these days. So, i've had to turn to old data to re-process, and this data set was an obvious candidate as i was never happy with how it came out originally. And looking back on it now with fresh eyes, boy did it need it! Nikon D5300, SW 80ED, HEQ5-Pro. 3 x 1200s, 2 x 1380s, and 4 x 1500s of Ha 9 x 1200s of Oiii. 11 x 480s with an IDAS-D1, for RGB stars only 7 Hrs 54 Mins in Total. Stacked in APP and processed in PS. Combined as SHO (using a 70/30 blend of Ha/Oiii for the Sii). The main differences this time were, using Starnet++ to create the starless versions, using more Ha in the synthesized Sii (70% instead of 50% last time), but mostly the improvement has come from toning down the stretch a lot (ok, a heck of a lot!) before making the colour map for the tone-mapping. From then on it was immediately apparent that i'd made a massive boo-boo first time round 🙈 I've included a 1080p rotated crop too, as i quite liked the framing. Feels like ages since i last did any NB imaging. I almost forgot how much i enjoy it! 🙂 And rather embarrassingly, here's the original. Try not to laugh too hard! 😂 😂 😂

Thanks for all your input guys. I asked over on the QHY forums and the answer I got direct from QHY was...'This is normal, it is because the OFFSET of this chip is added after the ADC, so it doesn't change with the gain'. Does that explain things then? @vlaiv that's interesting about the first few lines of pixels. I copied the files onto a 64GB USB3 flash drive before moving them to my desktop and uploading them to the cloud. There were no problems with copying them AFAIK. Although it's a little worrying that there is variation between the subs. How did you identify this if you don't mind me asking? And when you mention the possibility of this causing problems and taking steps to avoid it, what do you mean exactly? @wimvb I had another look at a Dark and Bias in SGP. I've pasted below the statistics for both. Do these look normal? Based on what you said above, I would expect the Dark to have a higher Mean ADU than the Bias, but it's actually lower. BIAS: DARK:

Hi guys I recently picked up a used QHY163c, and i noticed something strange while taking some calibration frames. I can't explain it, so thought who better to ask than the fine SGL community! Basically, whenever i take some Bias or Dark frames, SGP shows the Median ADU amount as being precisely twice the value of what i am expecting. As SGP reports the ADU count in 16bit, and the QHY163c is 12bit, then AFAIK all i should have to do is divide by 16 and the result should be equal to (or very very close to) the Offset value. I tested numerous combinations of Gain and Offset, but the result was always twice as high as it should be. I've included links below to 10 Bias and 10 Darks. They were taken recently, indoors at night, at Gain 80, Offset 35, and at -15C. Nothing else was connected to the laptop other than the camera. SGP shows the Median ADU as 70, instead of 35. Everything is seemingly working fine. No crashes or hangups, and files download in about 5 secs, so everything seems ok on the surface. I wonder is it possible the firmware is doubling the Offset behind the scenes somehow? I'm convinced the camera is fine, it's just i can't explain what is going on here, and i want to make sure it's not anything silly that i am missing, or if it is even going to be an issue for me going forward. Note, i still haven't given the camera a proper first light test yet, but there's a chance i might be able to tomorrow night. Thanks in advance for any advice! Bias: https://1drv.ms/f/s!AhhWC3D3zU7BpQjaXQo83p953Thp Darks: https://1drv.ms/f/s!AhhWC3D3zU7BpQlBlAUwG-8L2szP ps - The Darks were 180s long, and the Bias were 0.3s long (as i know Bias don't work at extremely short exp times with these cameras).

I'm just looking on my mobile Adam, but even so it's obvious that the new version is a huge improvement, as the original looks like it may have been black clipped, and you've managed to bring out an awful lot more of the surrounding Ha. And at our latitude this is not an easy target at all, so congrats on a great version of this iconic DSO. In fact, your image has convinced me to ignore the lack of any astro dark over the summer, and rather than down tools, just get on with doing some NB imaging, so thanks! 😁

I don't see any differences between this and the original Carole. Did you post the wrong one by mistake? ps - How does your HEQ5-Pro handle the 120ED? What's your typical RMS, and are all your subs usually keepers?

Very nice Carole! As others have said, it does indeed look like it's name. I'd maybe try and play with dropping the black point a tad though. We have the same mount (HEQ5-Pro). I've often wondered if a SW 120ED was too much scope for it, but seeing that you are pulling off 10 min subs with this very same combo gives me all kinds of hope 😀

Absolutely brilliant Gav. I'm sure a LOT of work went into this.... and it shows. I'm sure BBC/Sky at Night would be interested in this 😉

The early bird catches the NAN! Looks great Richard. Not sure why exactly, but my eye is drawn to the upper-left, and the teeny tiny stars look great 👌 Do you plan on adding any other filters to this? ps - Glad the Esprit is working out great for you 😀

Well Adam, I think it's fair to say the belt mod has been a resounding success! Didn't you say before that your typical guiding pre-mod was usually around 1.5" (and that was with the 80ED?!), whereas this was much lower but with a much bigger, heavier scope, so it looks like a job well done! Not sure about the mushiness you refer to, I just see a great image. I'd be stoked with that. The only area I would experiment with would be sharpening. You've got shed loads of high-res, high-contrast details in the galaxy. This is also the highest-signal area of the image, so it could definitely take more sharpening to bring it out a bit more. Be careful not to overdo it though, and you only want to sharpen this area alone, and nothing else. Of course, how much sharpening to apply is very much a personal choice. So if you don't like what it adds then by all means leave it well alone, as it' already a cracking image 👍

Very good. Always love seeing images of this, as there's not many flying around. And with good reason, as Adam says it's a hard one to get, so well done! I presume you meant HEQ5-Pro? Or are you using an EQ6? The 190MN is an amazing scope, but I would have thought that it was too heavy for an HEQ5.

Nice! ?

I like that Adam. I love these widefield shots with the main stars accentuated so you can more easily see the outline of the constellations. Betelgeuse is looking lovely too! Just one small bit of feedback - the stars look a little green on my monitor. I'd maybe try a quick pass of HLVG on a colour layer to see if it helps. ps - Is that a meteor you captured as well, just above Betelgeuse?

Amazing. So much detail, with just the right amount of saturation, and the stars are as good as perfect too. Very good indeed!

Did you use APT for all of the subs? Lights and calibration files? It sounds like Gain is a recent addition to the Fits header info. Clutching at straws a bit here, but you could maybe check your APT Log file with a fine tooth (no pun intended! lol) comb. Look specifically for Gain and Offset values for all the calibration files and Lights and make sure they match. Or if you'd like i'd be happy to take a look at the data for you, just to see if i get the same outcome. Even just a subset of the full data should suffice. Say 10 subs of each would do.

Not being a CCD user, i'm not sure if any of this is material or not, but i notice in the Fits header info that the Gain for the Darks is 0, but it's -1 for the Flats and Dark Flats. Also, the temp of the Flat is about -1 degree C colder than the other two. Could either of these be the culprit i wonder? I would at least try and get the temp of the Flats a bit closer, just in case that's it. I don't see any info regarding Offset. Are you absolutely sure all of the files (both calibration and lights) have been taken with the same Offset? Weirdly, only the Dark has an entry for 'Telescope' in the fits header info. The other two are missing this option entirely. It's a strange one alright. But right now my hunch is that there's nothing wrong with your optical train or gear, and that the most likely reason is just something silly that's gone wrong during acquisition of some of the subs.

That's a good point Adam. APP is now 'smart', so it is supposed to handle the files automatically for you. I still manually select mine one batch at a time (just because I've been doing it that way since the earlier versions, and, well, I'm on old dog, lol) so I don't know how well this functionality works. If you throw it files it doesn't actually need, will it ignore them? Or does it just know how to handle all the myriad calibration files, assuming you've selected all the right ones to begin with? Not sure tbh. Another tip for you regarding APP - you don't need to finish a stack to know if calibration is working or not. As soon as you've finished Step 2 (Calibration) you can select any Light sub from the list at the bottom, and change the drop-down box at the top of the screen from 'Linear' to 'l-calibrated'. This will show you what the Calibrated Light sub looks like, and it should be obvious if it's working or not. If the Bias files don't solve the problem for you - thinking outside the box here - you definitely haven't mixed up your Atik and QHY flats by any chance?