Xiga

Thanks Vlaiv, very enlightening as always! I use Astropixelprocessor for stacking, which I think uses Lanczos-3 and Mabula's own custom interpolation algorithm, which he coins 'Adaptive Airy Disc'. But I agree, I think we've veered just a tad off-topic here, lol, sorry Gerr! ☺️

Thanks Vlaiv. I'll admit it's really not that easy to tell which image is which in your example, which I wouldn't have imagined. I suppose with an OSC one will always want to use Bayer Drizzle. I only really used it once myself, on an image of M31, and I recall there being a noticeable improvement. So maybe the true resolution when using Bayer Drizzle isn't quite the full resolution, but is probably a lot closer to it than twice the value, would you say?

Hi Gerr I also have an HEQ5-PRO. It's currently getting the StellarDrive treatment by Dave at DarkFrame. I've recently picked up a used RC6 for galaxy hunting. It's definitely at the high end of the scale for the mount, but as long as you don't aim for too high an imaging scale, it should handle it ok.

Forgot to say, Mabula (the creator of Astro Pixel Processor, which I am a big fan of for calibration and integration) suggests not to use SuperPixel mode for over-sampled OSC images, as the lower resolution would affect registration. What's your opinion on using Bayer Drizzle (with appropriate droplet size) and an integration scale of 0.5 instead? https://www.astropixelprocessor.com/community/tutorials-workflows/does-app-support-software-binning-of-osc-color-images/

Hi Vlaiv You say that for OSC cameras the true imaging scale is actually double what one might think it is, due to the Bayer CFA. But what if one were to use Bayer Drizzle rather than an interpolation algorithm? Does this effectively bring the imaging scale back down to half the amount again? Richard Sweeney's recent amazing image of the HH Nebula comes to mind. He used a 2600mc camera with a Tak Epsilon 160, so roughly 1.5" resolution. I'll admit I am having a hard time accepting that it's really a 3" image it's that good. Ps - part of my reason for asking is that my next camera will be either the OSC or Mono version of the 2600. My head says go for the simplicity of OSC, but.......

I agree with Martin, Adam. You already have the base here for a truly great image, it just needs some RGB to make it complete. Keep going! Ps - I wish I could shoot this. Alas, most of the big winter objects are blocked by trees here 😭

Thanks Vlaiv, that makes perfect sense 🙏

Vlaiv, i see you mentioned 45cm for the RC8, but what about for the F/9 RC6? What prism to sensor distance would you have to stay under to keep the guide cam from effectively being stopped down?

Very nice Emil! A big improvement over the original, and I really like the colours. ps - Annie's action is a nice time-saver, but you can take full control of it if you want. When you run the action and the Levels window pops up, choose not to do it. This stops the action. You're then free to manually balance the Levels and then move on to doing as much of the Selective Colour adjustments as you wish. pps - You can go further and actually edit any PS action you want really. If you look at the list of Actions on the panel, you can click on the arrow beside them, and drill down to see the order of steps and exactly what each step does. You can choose not to run one particular step if you like, or edit it to do something different.

Thanks Richard. The little I have used of it so far myself, I have only really used the Denoise slider, and even then I have tended to use a setting of between 1-15 (not sure what that is in % terms) and even then it's usually been closer to 1-5. I have also noticed that even if you have the sharpening slider set to zero, it still applies some sharpening! For example, if you run it on an image with stars, you will see that even with sharpening at 0 it still makes a mess of most of the stars. Perhaps it's not actually sharpening though, and just the effects of how a noise-reduced background sky looks against a star. Either way, they don't look good. So I have taken to fixing them afterwards with a good star mask. If used correctly i do think the tool has it's place in a workflow, but i can definitely see how liberal useage of the sharpening slider might upset a few people. Personally though, it doesn't bother me at all. To me, it mostly looks like it is enhancing details rather than adding them, but of course it's all down to how it is used, and i do agree it is a good idea to mention that it has been used in an image. ps - I did a little searching and found the two images below on Astrobin. I think they were by the same imager that someone mentioned earlier in the thread. He got an APOD for the first one, and one person in particular really went after him in the comments. The comments in the 2nd one were thankfully more respectful, and generated a decent debate at least. Food for thought. https://www.astrobin.com/6ooyr1/B/?nc=user https://www.astrobin.com/6oovs5/H/

I haven't been on the scene much lately, but when i saw this on my phone i knew i just had to go and boot up the computer, so i could see this one properly. Wow! Truly amazing work Richard, even by your standards. I could honestly look at this all day long and never get bored. Absolutely stunning. Good use of Screen instead of Lighten btw. Screen does add a lot of noise, but it also boosts signal and detail significantly too, so evidently with your combo of scope and camera you have more than enough signal to negate the extra noise that Screen brings, so good call! ps - Was it specifically Topaz Denoise AI that you used? Topaz have one called just Topaz Denoise, as well as the AI one (which uses machine learning, similar to Starnet). Assuming it is the AI one, i think you are correct that it does indeed alter the data. Apparently the AI version has caused a bit of a ruckus in the Planetary scene of late. I don't know the specifics, but i'm guessing it is adding details (e.g in Jovian cloud bands) that aren't actually there maybe? I myself have recently added the AI version to my own workflow, but only for NB data and only in the areas of very low signal. I find that it works best here, as NB data is generally very noisy, and the AI version does an amazing job of removing the noise, compared to general NR routines which just smear the data. I'm not so sure of it's use in RGB imaging, although i haven't really tried it. In your case, with a large aperture scope and a very sensitive camera, you might need to be very judicious as to where to apply it. If you do put up a comparison, i'd be very interested to see the effect.

Did you get a new scope Adam? I had only heard of the Sharpstar Newts, I didn't know they did Fracs too. F4.4 is a nice speed increase over the 80ED's F6.3. I take it this is uncalibrated? It might be easier to diagnose if it was calibrated. I would say none of the corners look right if i'm being honest, although a Full Frame camera will certainly be testing things to the max. To my untrained eye, I would say the top-right looks worse than the other 3 corners, so if I had to guess, i'd say you probably have both tilt and spacing issues going on. Perhaps someone more experienced in diagnosing these things can chime in though. Next time out you could try a more densely populated area to pull in as many stars as you can (open cluster or anywhere near the Galactic plane etc). You could also try a shorter sub (15 secs at ISO 800?) although I highly doubt you had tracking issues with your Mesu. Good luck!

Well done to Rob63, Zihao, and especially Skipper Billy! Really enjoyed seeing everyone's entries 😀

Just had another thought. You most likely captured your 6 panels over multiple nights. What are your plate solving settings in SGP for degrees of rotation? I only rotate manually myself, but I still like to aim low on rotation, usually something like 0.7 degrees, because over multiple panels the +/- error can really begin to build up. Oh, one other thing, when you come to build the mosaic, make sure you are selecting the most central panel as the reference frame. APP doesn't guess this very well, so you usually have to tell it which one to use.

I'm only on my phone, but these look great Adam, especially the Soul. So much signal! You say APP is struggling with your 6 panel mosaic of the Spaghetti Nebula. What % of overlap were you using in SGP? I can't recall what the default is, 15% or 20%, but I usually just stick with it. For small mosaics like 2 panels, you can drop it a bit, but for larger ones you can run into problems if there aren't enough overlapping stars for the registration to work.

Adam you probably already know most of this already, but i'll repeat it here for anyone else interested. I had my Nikon D5300 modified by JTW about 4 years ago now. The cost for the modification was about £175, but after including postage (both ways) it came out at just over £200. I think I had the camera back again within 2 weeks, if I recall. I am very happy with how the camera performs, and I can't ever see me selling it. FWIW, I totally agree with JTW's answer above in quotes. After I got my camera back, I did quite a lot of Ha-Oiii bi-colour imaging with it for a couple of years, using 2" Baader filters. I kept reading stories online of how the Oiii halos were really bad with the Baader filters, but I never saw them in my images. Even 52 Cyg in the Western Veil showed minimal halo-ing. I've recently just started doing some mono imaging with an 8300 camera, and even though I have only taken one data set so far, I am now seeing fairly significant halos in Oiii (and also Sii now that I've picked one up). So I think it's fair to assume that the internal longpass filter that JTW install is of very high quality, and by the looks of it, has better coatings than the sensor window of the 8300 camera.

Here's my take, all done in PS. Used starnet to remove the stars, then add them back in again in blend mode Screen and with a much smaller stretch. Tonemapping done for the colour. Amazing data, wish mine was as good as this, so thanks for sharing! 😀

Thanks Miguel! Thanks Spock. Logic dictates, therefore, that I got the colour balance right on this one 😉 Cheers!

Topaz Denoise Ai can work wonders on some images, and not work at all on others. It does seems to work well on NB i've found (so far). You do need to crop off those borders first though! It does indeed destroy small stars Adam, so you either need to protect them with a mask, or first remove them with Starnet, and then add them back in in blend mode Lighten. It also doesn't surprise me that you find it harsh even at a setting of 1. With your 180mm of aperture, your needs are less than most. I often need something in the region of 5-15, but for your setup, you probably would need to either use the 'Recover Detail' slider, or just bring the Denoised image back into PS, and use a combination of a mask and the Opacity slider to find the right balance. Experimentation is the key to making it work with your setup.

Very nice Adam. FWIW, i completely agree on the green front. The noise is probably down to the level of stretch. The Ha is so dominant here, that it's often enticing to try and bring the other channels up to the same level. Recently, i've started to go the other way, and actually tone down the Ha stretch quite a bit. This way, you don't have to boost the other 2 (usually noisier) channels quite so much. The result it usually a darker, moodier image overall (personal choice of course, but i quite like that, even though it's taken me quite some time to realise it). If you aim for a roughly similar Mean value in PS for each channel, that's usually a good starting point for combining the colours.

I totally understand your sentiments Adam. We do get attached to these things, don't we!? I feel exactly the same way about my modified D5300. It was my first proper astro camera, and i will never sell it. Not just because of the sentimentality of it, but because it's still bloody useful. I do agree with Martin though. This project really needs the Oiii to get the full Tak treatment to make the most of it.

Thanks Martin, that's great feedback. Vibrancy is something i usually add as one of my final steps in processing, but on this occasion i applied very little, as i didn't find the image to respond particularly well to it, so i thought it best to hold back.

Thanks Richard. In fact, i actually went out of my way to suppress some of the background dust you mention, mainly because i wasn't sure if it was truly background dust, or just residual mist/clouds! 🤷‍♂️ The conditions really were pretty poor.

Thanks Adam. Tbh, no I hadn't. Even the thought of running a dual rig without a permanent setup is making me shudder, lol. Each time I decide to image, I have to carry everything down from the attic (2 flights of stairs) and setup completely from scratch. Then break it all down and carry it back up again once done. From the moment I decide to start fetching the gear, it usually takes me anywhere from 60-90 mins until the first sub is on it's way, so I am always looking for ways to simplify and speed things up. While the benefits of a dual rig would be nice (I never have enough data!) I simply can't see me carting a dual rig up and down each time. And then there's the added complexity of making it all work together, dithering, etc, etc.

Thanks Phil (I hope that's your name!). I don't normally shoot clusters myself, but this made for a nice test target given the conditions and short timeframe. Thanks Michael. Cheers Space_d 👍