Xiga

With no imaging possible at the moment (the weather has been awful lately, nevermind the lack of Astro Dark), i thought it would be fun to re-visit this data set and have another go at it, as i couldn't achieve anything even approaching decent with it this time last year. Long story short, this is easily the worst data set i've ever had to work with, and i'm used to not having much even at the best of times. This is 80 mins in total, consisting of 12 x 300s of Ha, and 4 x 300s of Oiii, shot with an OSC camera, under terrible conditions (bright sky and intermittent clouds). The Oiii subs were especially bad, but at least it allowed me to get a bit of blue towards the centre. SW 80ED; HEQ5-Pro, Qhy163c I've been playing around with Topaz DeNoise AI in PS lately, and have been impressed with what it can do in certain circumstances, so i thought this data set might make for a good torture test. Both versions below are crops, the first just to crop off some of the noisy sky background that didn't have any nebulosity, and the second a tighter 1:1 crop to show the pillars in the vertical position. I've also linked to the original version from last year as well 😳 CS!

Hi Richard Another option worth considering is the IDAS-NBX. It won't be out until August, but it looks very promising. 10nm bandpass at both Ha and Oiii, but importantly they are quoted as working as far down as F2. https://digiborg.wordpress.com/

Hi guys I decided to make one final adjustment to this, before finally putting it to bed. The dark dust lanes, although not clipped anywhere, were indeed still very dark in places. There was some faint dust hiding in the shadows, so i decided to bring them up in this final version. I think it looks a bit more natural now, so i'm finally calling this one done! 🤪

Yep i totally agree Martin. The reason i wasn't sure which one i preferred was purely down to aesthetics, which of course is subjective. I think i just needed to step away for a few days in order to see things more clearly. Luckily, work and family life makes that all too easy, lol. Your point about people liking overly saturated images is absolutely true. Looking back over my AB images, the ones that were the most popular were the ones that i now definitely think were over-processed!

Wise words indeed Brendan. Moderation is indeed key. I've only just looked at these again for the first time since the weekend, and i'm now comfortable with the new version's lower sharpening & contrast. Thanks for the feedback and sage advice

Really great M101 Ian! If i didn't already know it i would have guessed this was 2 or 3 times the integration. For me the synthetic Lum version has added a lot. The sharpening looks spot on. 👍

I had a bit of feedback that the Pelican's beak was over-sharpened, and (if i'm being honest) this only confirmed what i think i already knew deep-down. Luckily i always make a point of saving my images with lots of layers in PS, so i was able to revert back to before i went a bit overboard on the sharpness & contrast. So for this version i kept the same colour but went the complete opposite way in terms of the Luminosity and applied hardly any sharpening and contrast adjustments. I've come to realise i may be something of a contrast junky 🤪 (mid-year's resolution to rectify that) so part of me still feels like this is lacking a bit of punch, but then again, there are elements i prefer. I think the stars inside the nebulosity look better for instance. Interested to hear what the good SGL folk think. Better? Worse?

Simply breathtaking. This should come with a health warning. You could get lost in this for hours!

Looks good Adam 👍 Think you were right to dial back the contrast. After 6 or so craft beers I think I went a bit overboard last night 🤪

🤣 The problem with that Adam is i would end up trying to crank the slider to 150% I actually didn't do any NR on the jpg at all. I think what you are seeing is just the noise being more hidden due to the lower overall brightness. In fact, about 75% of the impact came from just a simple s curve adjustment. This brought down the brightness in the lower-left of the image, and allowed the wall to stand out more. After that it was just a few tweaks - a touch of the clarity slider in camera raw, one of Annie's Actions to reduce star bloat, some selective colour adjustments to add back in more green, some de-saturation (to all colours except green, as there wasn't much to begin with), and finally a bit of Topaz Detail in just the wall itself.

I also couldn't resist it either Adam. If i get banned too at least myself and Brendan can keep each other company 😋 My style is definitely closer to the 'over-processed' end of the scale though 😬

Really nice Adam, great work! It has a subtlety to it, something i should try and aim for myself (i definitely allow myself to get carried away all to easily!). I wouldn't say it's too soft. Perhaps in places it could take a tad more contrast maybe? On removing the stars, one added bonus of not removing them (as you have done here) is that you end up with some star colour. I really like the star colours you've got here, if it were me i would much prefer these over just plain white ones. But if you do use Starnet and end up with white stars, you can always add the colour later. Just do another blend as you have done here, and run it through Starnet as well. Then layer the 2 in PS and set the Blend Mode to Difference or Subtract. This will leave you with just the stars, which you can then save and use as a mask later, to only allow through the colour of the stars.

Thanks Mars. Thanks Brendan Cheers Mark Thanks Martin. It was very tempting to up the brightness. I had to restrain myself from doing so right at the end. Hopefully I made the right call.

Thanks Adam. I totally agree on it adding depth. Although some of it is also probably just down to me taking a more considered, and less bright, approach to processing this time. I have a simple TS-Optics filter drawer attached directly to the camera, which is quick to use and much lighter than a filter wheel. For NB work though i will probably only be doing 1 filter per night (perhaps, on occasion, two in the long winter nights) so filter changing won't be much of an issue, so if mounting them at the front of the FF shows an improvement then i will probably just stick with that going forward and replace the filter drawer with a simple spacer. Another thought i've had, is to try putting the IDAS-D1 at the front of the FF and keep the NB filters in the filter drawer. I suspect that the IDAS has superior coatings to the Baaders, which might cut down on the Halos. If so, then i could retain the ability to swap out the NB filters easily. Although in my case the D1 filter line cuts off before the Sii line, so this would only work with Oiii. If it did work though, i'd probably sell the D1 and get a P2 instead. I don't think losing a few percent of lightpass from stacking filters would make that much of a difference either. ps - The Atik383l+ arrived this week (woop-woop!). Been too busy with work to even plug it in yet, lol, hoping to to that this weekend. So i need to get you your Qhy9 back soon. Thanks again for the lend, i may never have made the jump without it! 🙏

For reference, here was the Ha-Oii Bi-Colour version i had done the week before:

I finally got around to adding in some Sii to the Bi-Colour version i had previously processed last week. As it turned out, this was actually First Light for the 2" Baader Sii filter i bought last year. Now that i am using a mono camera, i am suddenly noticing halos around bright stars with the Oiii filter, and also the Sii filter. I used a Qhy9 for this image, whereas previously i was just using a DSLR (Nikon D5300), but halos were never a problem. When i used the D5300, i mounted the filters at the front of the FF, so they were always a good distance from the sensor. Now with the mono camera, they are as close as can be, so i am wondering if it is the distance that is the main culprit rather than the filters, or could it simply be a DSLR vs Mono camera issue? I hope to do a few Summer night tests comparing results with the Oiii filter in both positions with the mono camera to get to the bottom of it. Having previously done quite a lot of Bi-Colour imaging (albeit with a DSLR), i was interested on how much of an impact adding some Sii would make. Once i realised i needed to dial back the Oiii stretch i had used in the Bi-Colour image, and use a more evenly-balanced stretch for all 3 channels, i then started to see the impact more clearly. I consciously decided to leave some green and magenta in the image, to add depth and give the eye more to explore. Not everyone's cup of tea i know! 😄 All in, this is 100 mins in all 3 channels, so 5 hrs in total using 20 mins subs with a SW80ED on a HEQ5-Pro. Stacked in APP and processed in PS. Starnet++ was used for star removal early on in the process. Then much later on, Images Plus was used for a bit of star reduction. I've been processing this for the last 2 nights, and have spent far too long looking at it. So if you feel i have lost the plot somewhere along the way please do tell me, as i may have gone blind to it! CS and stay safe folks.

Very nice Carole! If you aren't sure how to get Starnet++ working, have a look at post #13 here:

Thanks for clarifying Olly. I was trying to visualise this in my head, but had forgotten about the Lighten blend mode. It makes perfect sense now, thanks! That looks splendid now Sir. Mine's an IPA thanks 😋 🤣 Once you see it, it's hard to unsee! It really does resemble a face with a closed eyelid. And is that a nightcap he/she is wearing? 😄

Richard, can you elaborate on this a little please? So you layer on the 'with stars' image in blend mode lighten on top of the starless one. This adds back the stars at their original size. So do you do an adjustment to this layer as well? Such as a downwards Curve adjustment to reduce their size, or something else? And then do you flatten (or do a Stamp Visible, same thing) and then layer this back on top of the 'with stars' image, and then reduce the opacity gradually until any dark halos around the stars start to disappear. Is that the general idea? So far I have very limited experience in doing this myself, but up to now I've only ever added the stars back simply in a Blend Mode Lighten layer. It sounds like you do it in 2 stages. Is that right?

Very nice Olly. I love this area of the sky. Probably because i have trees stopping me from capturing it from home (we always want what we can't have, right? 😋 ) ps - Don't know if it's just my monitor, but is the sky background a little on the blue side?

Thanks Richard 👍 This was my first NB image in some time, and i really should have heeded the sage advice i i once heard you mention.......rather than post late at night, leave it to the next day before finalising and posting. It's amazing how often you clearly see things you couldn't the night before!

Wow, talk about an optics test! Never mind the conditions, this still looks great in my eyes. The sheer number of stars is remarkable. When viewed at 100%, virtually every single one is resolved perfectly. The Tak & 2600 is looking like a nice combo Richard! ps - Maybe it's my SW80ED eyes talking, but i'm not seeing any issue in the corners. And in fact, i'm not completely sure I want to have it pointed out to me, lol. In this hobby, ignorance (if not quite bliss) is certainly easier on the wallet! 😄

Stunning image Alex. I've long wanted to do a mega mosaic of this area myself. I'd be chuffed with something half as good as this. Congrats!

Had a bit of a re-think and decided this was too garish, plus i think i processed the Ha Lum layer too aggressively, so i had another go and dialed back the contrast and colour a fair bit, and re-worked the Ha to tease out some more fine detail. Too tired to add in the Sii tonight. Will hopefully get to that in the next couple of days. It feels good to be doing NB again. My last NB data was from Nov 2018! 🤦‍♂️

As luck would have it, the skies unexpectedly cleared tonight, so i am currently in the process of shooting 5 x 1200s of Sii subs. This is the Sii filter's first light, so i'm looking forward to re-processing this with the full Hubble Palette. In the meantime, i thought i'd share a gif showing just how much i had to stretch the Oiii to bring it to the fore in the image above. I first took a basic DDP stretch and removed the stars with Starnett, then ran Topaz Denoise AI, and then finally did some Curve adjustments. Even though the data had been through the ringer, i was surprised just how much detail was left over. I only used it for creating the colour map, none of it went into the Lum. I think when i come to do a full re-process, i will try and include a small amount of the Oiii and Sii with the Ha when creating the master Lum layer.