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Friday and Saturday night were supposed to be clear, and the obsy roof was off and I was out getting everything ready - but in vain. Then on Sunday night, which had no great forecast (and I had to get up early on Monday), it was suddenly totally clear. The guiding suggested a modest seeing (RMS around 1"/pix) and SQM was 21.0, which is ok but far from the best I get here. I used my dual rig on the the Mesu 200 with ASI1600 for Ha on the Esprit 100 (3.5 nm Baader Ha, 46 x 10 min, gain 139, offset 50, -20°C) and ASI071 for RGB on the Esprit 150 (85 x 5 min, gain 200, offset 30, -15°C). Ha mainly added to the red channel using lighten in PS and a bit Ha added as lum. Stacked in PI and the rest in PS. Totally 14.75 hours.
EDIT: reprossesed the image to emphasize the dark nebulosity floating araound
Due to the poor UK weather I hadn't been paying much attention to how my automated imaging set up was progressing with this target. So, I was a little surprised when I discovered that it had been very slowly capturing data of this target for the past 6 months........Anyway, here's the result of 32 hours integration time of my first attempt at the Cave nebula (SH2-155).
The LRGB image below has an Ha blend into the L and Red channels and was taken with my Esprit 150.
L: 20, R:13, G:23, B:15, x600s, Ha: 41x1800s, DARKS:30, BIAS:100, FLATS:40 all at -20C.
After processing the Eastern & Wastern Veils separately a couple of months back, I've finally got round to doing the mosaic that was always the end goal (hence the framing of each panel). I'm not sure why I waited so long to do it, I think deep-down I was secretly dreading it really, as this is my first mosaic so I wasn't really sure how it would go.
So this is just 2 panels, and each one has 5 hrs of Ha (15 x 1200s), with 3 hrs 20 mins of Oiii in one (10 x 1200s) and 3 hrs 40 mins of Oiii (11 x 1200s) in the other. So 17 hrs in total.
APP was used for stacking, gradient reduction, and the mosaic creation. PS used for everything else.
Ha assigned to Red, Oiii to Blue, and Green was synthesized from one of Carboni's actions.
I've tried to push it as far as I dare to, did I over-do it do you think? I've resized it down to 66% to help hide some of the noise, and being a mosaic it's still plenty big. I might even end up bringing it down to 50%, we'll see.
C&C welcome as always. I tend to finish my images very late at night, so I can sometimes fall into the trap of not seeing the image as clearly as I should! So feel free to be as harsh as you like ?
We had a few hours of clear skies here on Saturday night, so I set about getting some O-III for the Western Veil, after I had collected the Ha last month. Thankfully, the moon wasn't around, so even though I didn't get that many subs (only 10) at least they were of good quality.
I actually fell asleep during the capture, and woke up to a 'Sequence Aborted' message in SGP and the sight of PHD2 going mad due to thick clouds. Quickly ran outside and thankfully there was no rain about (phew!). I got 11 subs in total, but the last one was totally unusable due to the clouds. The 10th one was affected too, but still looked useable to me, given that I know from experience that APP's 'Quality' stacking mode would know to give it less of a weighting, so I kept it.
So this is 15 * 1200s of Ha and 10 * 1200s of OIII (8 Hrs 20 mins in total).
Taken with the usual gear: Nikon D5300 (modded); HEQ5-Pro and a SW 80ED.
Calibrated with Flats, Bias, and a Bad Pixel Map. APP used for stacking and gradient reduction. Everything else done in PS (including running Carboni's 'Synthesize Green Channel' action).
After now having processed both the Eastern & Western Veils, I have to say I have found them to be among the hardest targets to process that I've done so far (although it's still early days for me yet, think I'm still under 15 DSO's and counting). I'm not sure if it's down to the sheer number of stars, or the very faint nebulosity that seems to be everywhere, but I've found the background to be especially difficult on these ones. Getting the Ha and OIII nicely balanced before combining probably has something to do with it. I also tend to do gradient reduction (which seems to affect the OIII a lot more than Ha) on the individual stacks before I combine them, so I wonder if I'd be better just leaving it to later in the process? (which I had to do again anyway, as there was still a noticeable red gradient visible later in the workflow).
Something to note, I did go quite heavy on the star reduction. More so than I normally would. I found it wasn't until I upped it significantly, that the nebulosity really started to take centre stage. I like the impact it has made to the image overall, but it made me feel a little dirty at the same time, lol (if that makes any sense).
Also, this isn't actually the finished version just yet. I have a bit more work to do on the background and stars (which need their colour toned down in places - probably shouldn't have ran Carboni's 'Increase Star Colour', in hindsight I don't think it needed it). I was literally falling asleep at the monitor last night while attempting to finish it off, and in the end had to admit defeat. So hopefully I can get around to it later tonight.
Then the next thing will be the big mosaic of both Eastern & Western Veils. I'm both looking forward to, and dreading it, in equal measures ?
As always C&C warmly welcomed!