The Admiral

That's a beaut image Nige, I'd be very pleased if that was mine. I don't think I've seen as much dust cloud as this shows. I can't wait for it to come around at an hour I can cope with Ian

Don't know about that one, but I hear that the Samyang 135 f/2 is very good. Have a look at the Polish lens review site - very thorough: http://www.lenstip.com/index.html?test=obiektywu&test_ob=166 I'm not sure that Samyang make fly-by-wire lenses. Ian

Yes I've just tried the hue sliders but they don't really make much difference. May be some more tinkering. I guess that the only problem in splitting the stars from the nebulae is the creation of a mask, but my attempts so far have been dismal on account of the abundance of stars. Again, something I'd need to spend some time on. Ian

Thanks Ken. I think I'm actually oversampling, but I software binned to 25%, and on a whim tried the Flux option in ST which does some sort of fractal processing - I need to check that one out . As for colour, I agree more red than magenta, but so far if I'm not careful the stars around the nebula take on a greenish tinge. Of course, this is often imaged in narrow band, which will take out the star intensity I guess. Will NB be your next step? Ian

A couple of nights ago I re-targeted NCG6888, the Crescent Nebula. Previously, I'd taken 121 subs and this time I took 241 with the target much higher in the sky, and I think under slightly better conditions. I rejected a number of frames as showing what I regarded as 'significant' trailing which left me with 88 from the first session and 163 from this last, or 251 in total, and over double what I used for my previous post (https://stargazerslounge.com/topic/228101-the-no-eq-dso-challenge/?do=findComment&comment=3091544). These were stacked in AA using bias for darks and the flats from this last session for both sets. I processed in ST, but I found this tricky and, to be honest, my results always look a bit messy. This I think is largely due to the very high star density in this area of the sky, and also I stretched heavily aiming to get every bit of nebula extracted. I felt I needed to do a bit of tweaking in LR after the event as well. The full image is a bit overwhelming, so I've also posted a small version which I think gives a better impression of the nebula field, as individual stars are less able to be seen. I can't say this image makes me really happy, but it is a record. I think in reality I'm scraping the bottom of the barrel here as I suspect there are too few photons landing on each pixel to get a decent picture, however many subs I use. The Bubble Nebula is also lurking in the top left nebula, by the dark dust lanes within it, not that you can see it Ian

What stars are you using for alignment? I only use 2 star alignment about the region I'm imaging, and both GOTO and tracking are usually good. Ian

Well I managed to capture it with just 64 x 15s subs using my 102 refractor and an unmodified Fuji X-T1 (though its red response seems pretty good), but it was very marginal. You do need a motorized mount that tracks really. https://stargazerslounge.com/topic/228101-the-no-eq-dso-challenge/?do=findComment&comment=2872568 And then I did one using 250 x 10s subs, here, which is rather better https://stargazerslounge.com/topic/228101-the-no-eq-dso-challenge/?do=findComment&comment=2889900 This year I plan to do it justice though, and spend some time on it. Ian

I suppose at the back of my mind is that the sort of mount used shouldn't impact on the quality of images that can be obtained, with a few provisos. One is that the precision of tracking with AZ mounts, and hence star streaking, is unlikely to be as good as a properly tuned EQ mount. (May be we need mounts specifically designed to cater for this sort of imaging, but that of course is breaking with established doctrine). This will lead to somewhat larger stars once stacked, though I guess with enough subs one could ruthlessly discard any showing a hint of movement. Ultimately, though, this will result in a reduced total exposure per session. Also, the field rotation constraints mean that our imaging 'window' is quite limited compared to EQ mounts (i.e. 2 or 3 hours compared to all night), requiring a number of imaging sessions on a given target in order to build up sufficient quality, and the co-operation of the weather to achieve this. AZ imaging time is precious! Further, we are probably constrained to below the optimum exposure times, but for many in rather less than the ideal dark sky conditions, this may not be a particular constraint. Well, perhaps I've argued against myself here , though I think we all know that AZ imaging does impose constraints, but I still feel that if we get it right then there should be no reason not to be able to match the quality of the best images produced using the 'conventional' paradigm. Heavens, we are already producing images which are better than some produce using all the fancy gear, but that's another story . But we still do have something to aim for - getting it right is not so easy! Ian

I used 15s subs when I last attempted it, and that was without a 0.79x reducer, which I plan on using next time. I also plan on using ISO400 rather than 1600 which should give me a bit more DR. So I agree, 5-10s looks to be the likely range. The next question, what proportion of imaging time should be devoted to short exposures and what to long? Looks like a few experiments will be needed - let's hope our weather co-operates . Ian

That's a lovely image Ken, well done, and again, congratulations on your persistence , which is clearly paying off. I prefer your v2 for colour. Your short exposures to capture the core really are a heads up here, as I've been wondering what sub duration I should use when I get around to it later this year/early next. I plan on blending two sub durations so that will be a first for me. Ian

Here's another from a couple of nights ago, NGC6888 Crescent Nebula. This was not in my darkest direction, running the gauntlet of sky-glow from the local town. It was taken after the Veil nebula and so it was starting to get a bit low in the clag. This is the result of 121 x 30s lights at ISO1600, stacked in AA using the master bias for both flat-darks and darks. Still looks a bit 'mucky' despite being given a right buffing-up in Lightroom. Not one of my best, really needs more subs taken at a higher altitude. Taken with a Fuji X-T1 through an Altair 102mm f/7 Super ED with a TS Photoline 2" 0.79x reducer/flattener. Mounted on a Nexstar 6/8SE Alt-Az mount. RAWs stacked in Astroart, processed in StarTools, and finished in Lightroom. Ian

Another one from the night before last. This is looking towards an unfavourable direction for me, where light pollution from a local town is a problem, though with a clear night it wasn't too bad and the Veil was high in the sky initially. This was a result of a quick processing session, and with a bit of post-post-processing work done in Lightroom. As always, though, I'm never satisfied and want to improve my result, but as more often than not I end up with something worse. I've tried to bring the nebula more to the fore, but I think it now looks a bit false and less diaphanous (nice word, that!). I think I prefer the first one. I took 180 frames at ISO1600, and manually weeded out the ones with apparent movement, so in the end I stacked 137 x 30s frames in AA. I took darks that night, but couldn't unscrew the lens cover (it had frozen on!), so had to do the flats the next morning. Gear as usual: Fuji X-T1 through an Altair 102mm f/7 Super ED with a TS Photoline 2" 0.79x reducer/flattener. Mounted on a Nexstar 6/8SE Alt-Az mount. RAWs stacked in Astroart, processed in StarTools, and finished in Lightroom. Ian

Well, that's less likely to happen when you've got to drag everything outside each time you want to image! Just envy, really Ian

That's a fine image Ken, a testament to your patience (well beyond mine ) in your pursuit of excellence. I see a perfectionist at work! I'm pleased that your camera is also working well for you. I've no doubt that we've all come a fair distance in this game, and beginning to knock on the door of the more 'traditional' imaging techniques, and long may it be so. Ian

My triplet seems fairly focus robust, but I guess Ken that your software control allows you to monitor what comes out fairly quantitatively and you'd be fairly sensitive to change. I just look at my camera LCD and eye-ball it . Perhaps I'm just a slovenly operator, but I don't really need to re-focus. Mind you, it's darned cold out there tonight so I ought to check. Ian

Fair point, but given that ST needs you to crop out the artefacts anyway you might as well go with the standard or intersection mode, and not lose anything. Ian

I think that's come out rather well Nige, especially as you must have been imaging through a load of dirty atmosphere. And as you say, I too find it amazing what can be pulled out of something you'd regard as noise if you didn't know better! It'll be interesting to see what you get with your other stack. Ian

Haven't we been down this avenue before? Your FITS shouldn't be that big. Have you got something switched on in DSS that shouldn't be, like drizzle or mosaic? There's plenty of data there to play with. Have you tried using the RGB Max button in the colour module? That can get you near the correct colour balance. I must admit I generally use the manual develop mode, despite Ivo extolling the virtues of the auto dev. I found it quite sensitive to the placement of the 'region of interest' box if that is used. If it was me I think I'd crop it some more, but each to their own. Bear in mind that this isn't the easiest of targets, and even in the best images it somehow takes on a somewhat fuzzy appearance to me. Ian

That's where a new forum topic would help! I'll get me coat! Ian

Thanks Jon. It's getting a bit frenetic on this thread, and what with sorting out my own images I'll have to catch up later! Ian

Thanks Ken, agreed! Here's the same but with less of the top cropped off. Ian

Great night last night, here's hoping for its equal tonight. Last night I re-imaged my attempt on M45 of a couple of nights ago, and I think the conditions were rather better. I took 180 x 30s subs at ISO400 and stacked 132 of them in Astroart, after weeding out the clearly trailed ones, using the 60 x 30s darks I took at the end of the session. Here's my first go at processing this set, with I admit quite a lot of fiddling in LR at the end. I find it good it noise reduction, sharpening and selective colour enhancement, or at least, easier than to do the same in ST. I was wondering about the reddish hue at the top and wondered if it was noise left over from the wipe. Here I've upped the red saturation to enhance its visibility. Having looked at Rogelio Bernal Andrea's superb image, which can be found here and here: I think it's the dust cloud beginning to show. Usual gear: Fuji X-T1 through an Altair 102mm f/7 Super ED with a TS Photoline 2" 0.79x reducer/flattener. Mounted on a Nexstar 6/8SE Alt-Az mount. RAWs stacked in Astroart, processed in StarTools, and finished in Lightroom. Ian