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glowingturnip

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glowingturnip last won the day on March 19 2014

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About glowingturnip

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  1. glowingturnip

    Eagle Nebula (M16) SHO

    thanks very much both :-)
  2. I'm constantly fighting with the gamma and colour balance on my laptop and desktop - I find that my laptop is always a bit too bright and contrasty compared to most other screens even after I've calibrated it again and again, so have learned to finish up on my desktop screen otherwise I get dark dingy images. do run/dccw for the colour calibration wizard.
  3. glowingturnip

    Eagle Nebula (M16) SHO reprocess

    thanks Martin
  4. I had a quick look - the problem is that the raw file isn't colour-balanced - you can see it very easily if you turn the screen stretch off, you only see the core of Aldebaran and it's unmistakeably magenta. Try something like this - the colour calibration first, then the masked stretch. Play around with the parameters, setting the white reference upper limit too high seems to turn it green.
  5. glowingturnip

    Eagle Nebula (M16) SHO reprocess

    well look at that ! Magenta gone! By the way, when you mentioned white artifacts from deconvolution, you didn't mean this bit did you ? It's a feature, Nasa has it too ! I'm usually very careful not to let those white strings or bobbles come through from deconvolution, ditto any dark ringing or over derringing against dark background, but it is possible I've let a bit get through. Cheers, Stuart
  6. glowingturnip

    Eagle Nebula (M16) SHO reprocess

    ahhh that's a nice trick ! I must have made umpteen magenta masks, red masks, saturation masks etc etc, but I like the sound of that inverted SCNR, will give that a try tonight.
  7. glowingturnip

    Eagle Nebula (M16) SHO reprocess

    You may recall that a couple of weeks ago or so I posted up my attempt at the Eagle Nebula in SHO: At the time, I wasn't quite happy with the colour, and having looked back at it, I can see that at the initial linear RGB combination stage I over-egged the Sulphur, as it were, and made the weak Sii channel too strong in the mix. The rest of the processing from then was basically a fight against that. I had another go at remixing the RGB this weekend, and came up with these, which I think are better: Not going to win any awards, and I've still got magenta starbursts showing through from the Sii on some of the brighter stars, but I'm more happy with it this way. Hope you like them, Stuart
  8. glowingturnip

    Pacman nebula narrowband

    that's looking more like it !
  9. glowingturnip

    "T shirt" flats

    I set up and tear down too, but at the end of the session I leave the camera in the OTA and carry the two together (very slowly and carefully, considering how expensive it all got) back inside, remount it inside and shoot my flats in the morning.
  10. glowingturnip

    Pacman nebula narrowband

    I'd say firstly, ditch DSS and learn Pixinsight stacking, you should find it far superior (I'll probably get contradicted saying that !) - try Harry's tutorial for learning it - https://www.harrysastroshed.com/pixinsight/pixinsight video html/pixinsighthomenewbie.html So in your original image, you've got a mostly red nebula since as you say the Oiii and Sii signals are much weaker than the Ha, so they're not actually contributing to your nebula at all there, they're just giving you better coloured stars. In your second image, you've got a lot of green noise because the Ha channel has now been over-stretched in your attempts to bring out the other channels. There's some Oiii showing now, but still hardly any Sii. What they really need is that each channel has its own stretch prior to being combined together, so that they're all able to contribute evenly - that can lead to issues with stars (the infamous magenta halos). A method I like is a tonemap method, detailed here, though it it rather complicated - http://www.arciereceleste.it/articoli/translations/75-narrowband-color-composition-eng
  11. glowingturnip

    Pacman nebula narrowband

    nice image, and yes, there probably is more to be got out of it with processing, especially if you've got 6+ hours integration time Just wondering how you combined the Ha, Sii and Oiii ? The usual SHO combination would have a bluish middle and orange edges, whereas yours looks more like an RGB image ? Not sure about the cause of the black specks, but if you make sure you dither between subs, and if you're using Pixinsight, run CosmeticCorrection targeting the dark pixels on each individual sub prior to stacking and that should get rid of most of them.
  12. glowingturnip

    Prints on aluminium.

    Hahaha, as you can see we keep well-ordered and erudite bookshelves. Asterix and the Golden Sickle I think that one is, though we do have the full set. https://uk.whitewall.com/ for Jason's link - looks interesting.
  13. glowingturnip

    Narrowband filters

    in my limited exposure to narrowband so far, the way I'm thinking is that Ha is pretty much everywhere in the target, OIII is heavier, tends to hang around the centre of action of the target and tends to be less defined, and SII gets battered into all the wave fronts - so has the same overall structure as Ha without maybe the prevalence across the blank bits, but adds to the contrast, both in lum and in colour, in the areas of interest. I too wish there was a reference of which targets are strong in which wavelength
  14. glowingturnip

    Eagle Nebula (M16) SHO

    it's been a busy week, but I finally got round to tweaking the colour on these - what do you think ? I came up with doing the idea of a ChannelExtract of the c channel (saturation) from Lch, blurring and stretching that to use as a saturation mask, then multiplying it by a red+yellow mask from the ColorMask script then doing specific red+yellow desaturation with the ColorSaturation tool. I gave the blue a bit of a nudge higher too. Quite like how it's taken the fizz out of the reddish areas but left the delicate areas with a nice tinge. What do you think, am I on the right track ?
  15. glowingturnip

    Prints on aluminium.

    I got my aluminium prints back from Bonusprint too. Mixed results I'd say. The Bonusprint finish is matt, not like the gloss finish that I think Ollie got from his firm, and I don't think it represents what you see on the screen. My favourite of the below is the Lagoon - it actually has the look and texture of a painting (not what I was going for, but it works), and really comes into its own in tungsten lighting in the evening - it starts taking up a 3D effect with that darker stuff at the bottom in the foreground, leading back into the 'cave' with the 'lagoon' bit arching through the foreground. The hourglass is a touch blown though. The Helix print however has definitely lost detail - all those tendrils that point towards the centre have got blurred out a bit, though the way the faint outer wisp sits against the background has come out quite well. The Orion is just a bit flat, and not the crop I would have wanted if I had a free choice of canvas size. Apologies for the poor quality snaps, it's a dim dull rainy day here in London. (haha, just noticed my copy of the Pixinsight book has made it into the photo !)
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