Fegato

Nice one Göran! That does sound cold! We've got it "cold" for a bit now - it's forecast -3 tonight! Last night was our first full clear night here in W Wales since the summer... and I was away in London! Hopefully one or two more in the next few days. As for KN... I found an old paper referencing another PN called Kn 61, which includes this - "Originally found by Matthias Kronberger, a member of an amateur astronomy group known as the Deep Sky Hunters (DSH)" https://phys.org/news/2011-07-discovery-planetary-nebula.html

yes, that's why I thought maybe they've designed their own built-in camera, width less than the ZWOs etc.

Yeah I reckon a smaller RASA with a built in camera (hopefully perfectly backspaced and aligned, avoiding all that faffing around with image train).

I think "push a button" is a long way off. After all, we'd all want a different button! (take the same base data, and we all produce and want to produce something slightly different) Anyway - BlurX does a marvellous job of leaving all the tiny galaxies alone, as does StarX. I'm in the middle of a hell of job trying to mask these all before some heavy stretching to avoid super bright / saturated galaxy blobs all over the place! I need GalaxyX please....

It's a lovely image - quite a mesmerising colour certainly! There's lots of luminosity and depth to the whole thing too, so I'm not complaining. My recent effort on this looks dull by comparison, that's for sure. I guess you can have "too intense" if things are stretched or saturated so much that noise or artifacts start dominating. But mostly I think it's just "more intense" and "less intense". I often like images at both extremes - they show different facets of the scene.

thanks Charles! Yes HDRMT is a nice tool to have available and does usually do a good job, just a case of getting the balance right with the layers (bit subjective I guess, but I don't like it when it makes things too "flat")

thanks Chris! Yes, I could try adding some more, but I normally think an hour with the RASA is enough when shooting broadband, not least because I'm always impatient to move onto other targets!

I'd imaged NGC281, aka the Pacman Nebula, with a dual narrowband filter a couple of times in past years, but was prompted to add it to my list of broadband targets this autumn after spotting an image showing plenty of dust around a few weeks back (which I can't credit because I can't find it now, sorry). @cfinn beat me to it, with his excellent image posted a few days ago, but I've managed to get mine done now and here it is. I captured the data on Saturday. It was a rare clear night, but the wind from one of the weekend storms was strong - 20mph with gusts over 35mph. A bit foolhardy to try and image in those conditions... but sometimes beggars can't be choosers, so I risked it. I sat on the target for much longer than I normally would as I knew lots of subs would be wasted. Guiding was often at 2" RMS, and I had plenty of in-sub dithering! Anyway, the rig stayed upright, and with 30 second exposures, I managed to get just over 1 in 3 that were usable. Processing was a bit of a battle, mainly due to me stretching so hard to really push the dust (maybe I've pushed too far?). Firstly trying to control the brightness of the Pacman while bringing out the dust was tricky - in the end, despite a lot of masking, I resorted to applying PI's HDRMultiscaleTransform on the nebula, which worked quite well. And secondly I had a lot of colour balance issues. Red channel seemed very weak after stretching, even after careful background neutralisation and colour calibration, so I had to push it a bit. Not sure if my dust hasn't ended up a bit orange. I was interested to spot the little areas of reflection nebulosity and perhaps star forming areas above the Pacman in this image. One of the reflection areas is catalogued as DG6. I found an image on Astrobin of DG6 which pointed out that the area of dust around it looked a bit like a horse (lots of horses up there it seems!). This image is over 10 years old, and rather nice I think - bright colourful stars shimmering with just a faint ghostly horse visible in the background https://astrob.in/60471/0/. I attach a crop of my horse too - a bit puffy and unsubtle in comparison. Possibly this star removal business encourages us to go too far sometimes... Anyway - captured with RASA 11 v2 on CEM120, ASI2400MC Pro, 120 x 30s (out of 302 attempted)

thanks Olly & Göran! Seems to have become a thing of mine going for these sort of targets in broadband - a Pacman to come shortly. Lucky with the dark skies I guess, if not the clear ones!

I'm just processing my attempt at this now. Interestingly, that dark rift does actually seem to be full of dust - I can see that before doing much other processing. So while a dark contrast would be more dramatic, it's possibly not exactly what's there

You were probably better off in the cloud! It was clear here in SW Wales for a a few hours, but 20mph wind with c 36mph gusts. My rig was out and my guiding was often at 2" RMS, and although it's very heavy, I did wonder about it blowing over! I only shoot 30s subs so I'm hoping I might get 1 in 3 usable, but we'll see. My best bet would probably be to enter the Animation Challenge with an animation of my dancing and elongating stars, but I think that challenge is over!

Haven't got time to do anything right now, but might take a look tomorrow. First impression is that it's quite noisy, and you have a fair amount of "banding" type noise, which I think is common with DSLR / Canon cameras (although I'm no expert on that) - you can research that or someone will pipe up with a comment about how best to manage it. Obvious first questions are: 1. How much integration time went in to this? 2. What LP conditions were you shooting in, and were you using a filter of any sort? 2. Did you calibrate the subs (with darks, bias, flats...)?

I was pleased to grab three or four hours of clear sky between the cloud and wet on 1st and then 7th December. This allowed me to tick off another in my list of broadband targets that are more often imaged in narrowband. I went for a 2 panel mosaic to get a nice squarish field around the central targets of M52, the bubble nebula and companions, and to provide a reach from Sharpless 2-153 on the left to 2-156 (IC1470) on the right. There's so much going on in this field, plenty of which is uncatalogued. As well as M52 there is the smaller open cluster NGC7510 to the lower right, lots of emission nebulosity, dust and quite a few areas of reflection nebulosity. And then near the centre, that strange bubble-like planetary nebula NGC 7635. RASA 11 v2 on CEM120, ZWO ASI2400MC Pro, 250 x 30" (2h 5') across both panels

Yes, I think you certainly succeeded with that. Great advert for the Esprit 150 too... must admit I'd like that scope to complement my RASA. But with so little clear sky time here I just fear it wouldn't get enough use and targets would disappear before I'd finished them! I sometimes wonder about having one permanently down in Spain, but that's a lot of expense and complexity...

Sharpless 2-170 is at that location (and in Ian's list above). It's sometimes known as the "little rosette nebula".

I do see some funny coloured crabs that I really don't like. But that's lovely!

Nice one - this is on my list to do in broadband if I ever get a clear spell, as I saw another one fairly recently that revealed a lot of dust. Well done!

As the others say, best way is to capture two sets of subs for this target, and then apply some sort of HDR processing (I use Pixinsight, and the HDR processing works very well). With my last RASA attempt I used 20 second subs for the main shot, and a smallish number of 2 second subs for the core. To get to this I trialled shorter sub-lengths, looking at unstretched results until I had something that wasn't blown. Do your 8 second subs give you a non-blown out core and separation of Trapezium stars when un-stretched? If so, maybe HDR compression would still work. Not sure what post-processing tools you use and whether this is an option?

I've worked on the assumption of resampling to 300dpi - that's a sort of (high quality) benchmark for printing I think. I'm guessing somewhat less won't be too much of a problem.

I should add that I use Pixinsight and BlurXTerminator - the latter definitely helps a bit with star size reduction as part of the overall process

It's hard to manage a very bright star like that, and Alnitak is a favourite bugbear! Even starless processing generally leaves stuff behind which only grows with the stretches. I must admit with mine, I just decided it was part of the glory of the image and let it shine forth! I much prefer a big bright star than any obvious artifacts.

As vlaiv says, best result will always come from a single integration of all available subs. If the data is good, I keep all my light and calibration frames. Mind you, I have Welsh weather... so maybe there aren't so many of them! Must admit, the thought of having my own scope sitting in Extremedura is so tempting at the moment. Here I shoot F/2 to try and get the most out of poor skies. There - maybe F/7 max, so I don't get too overwhelmed with data!

Well, I was wrong in my previous post, a brief clear spell yesterday evening allowed me to complete this 2 panel mosaic. Panel 1 - 25th August, Panel 2- 6th November, just about sums up the recent weather. LBN 437 is a molecular cloud in Lacerta, and it sits on top of the faint emission nebula Sharpless 2-126. I wanted to capture the tail of dust up to the top right in this image, aiming to balance the emission and other detail to the left, and I think that composition works quite well. I find that StarXT is pretty good at leaving behind a range of small galaxies, and the main issue I had with processing this was avoiding these becoming large bright blobs! One or two aren't quite right, and I should probably try again. I guess PI's GAME script is probably the best way of dealing with these, so I'll probably have a go with that. With this I just used range masks... RASA 11 on CEM120, ZWO ASI2400MC Pro, about 2h 10' of 30" exposures across 2 panels. No filter.

My dark libraries are captured at -10. I would probably choose -5 if I ever get round to replacing them. The impact of dark current at these levels pales into insignificance as far as I can tell, so I'm sure I won't notice any difference. -10 is fine, except for occasional hot summer nights... I have once or twice had to compromise my subs at slightly less than -10... I noticed no difference calibrating with -10 darks.

Yes, looks like you have good data, it's just sorting the colour balance and contrast out I guess. I've been looking at my last attempt wondering about having another go... but you've reminded me how tricky it is, so I'm not sure now!!