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Filroden

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Filroden last won the day on January 24 2017

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About Filroden

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  1. It’s nice and subtly processed. You’ve kept it looking natural. My only feedback is your smaller stars are square.
  2. Are you creating a synthetic L from all that RGB data in the LRGB version? Given how much you collected, it may strengthen the L data. Is something going on at the edges of the image? I'm not sure if its real or an artefact but the border looks distinctly different to the main image.
  3. Nice method to quickly enhance contrast. The PS method is certainly simple to understand and control. For PI users, there is something similar in the LocalHistogramEqualisation. It doesn't need the mask and has a live preview option. Don't ask me what parameters to use - as ever with PI, trial and error! From the manual: "This process implements local histogram equalization with configurable limitation of maximum contrast enhancement. It is based on the CLAHE method (Contrast-Limited Adaptive Histogram Equalization). The main purpose of the process is to enhance local contrast and visibility of structures in low-contrast regions of the image. The process is designed to run on non-linear (already stretched) images. Histogram equalization takes the histogram and computes a transfer curve, which grants more brightness range to higher histogram peaks and less brightness range to histogram valleys. In other words, large areas of similar brightness get more contrast. Local histogram equalization works on individual pixels and computes a transfer curve from the histogram of a pixel neighborhood. The classical histogram equalization algorithm has the drawback of giving most contrast range to high narrow peaks, like a uniform noisy background. This problem is solved with the contrast limit property of the CLAHE method. This parameter limits the maximum slope of the transfer curve and prevents narrow peaks from getting too much contrast, effectively reducing noise promotion."
  4. As far as I know, you can't make it bigger. I've just ran into the same problem. Mine is docked in the side pane. You can change the size of the "container" but not the actual histogram within it It might be worth you floating the question in the Adobe forum and/or providing Adobe with feedback.
  5. Hi Rodd This is a tough one. I like the presentation of the first - both the wider context and the bolder saturation of the colours. However, I think the second is the better of the two images. The main things that swing it for me are you have colourless stars in the first, whereas the second image has coloured stars. They just make the second image look more natural. The other thing that swung it is that the first image appears "blotchy" in the background - almost like one "frequency" of structure has been over processed. The very largest scale structure looks good, and the medium and smallest scale structures are exquisite - but the large structures look "wrong". I don't see that issue in the second (but to be fair, the issue is most pronounced in the wider background which you've cropped out).
  6. I've a different take for Photoshop. I do a lot of non-Astro photograph and have always used Adobe Lightroom to develop and manage my photos. The photographers subscription includes both Lightroom and Photoshop, plus I've also got 1Tb of online storage for my photos. All for £15 per month. I used to pay £7 a month for 1Tb of storage anyway, so I'm getting Lightroom and Photoshop for £8 a month. That's a fraction of the cost of a decent filter or eyepiece or other accessary per year. Given how important the processing of the images are, why be reluctant to spend on the processing tools when you are willing to spend on the data collection tools?
  7. I wish my first attempts as astro-photography were so easily recognisable as astro-images! Well done. It gets better and easier from here Your M9 is much sharper than your M4. Did you do anything different? I'd recommend not using low numbers of darks (if at all). Unless your camera is cooled, darks could add more noise than they remove. Even if your camera is cooled, using only a small number of darks could likewise introduce more noise. I'd recommend taking 25-30 darks if I was using them as you can use better statistical rejection algorithms to combine them. I'm also not sure that your flats are fully working. You seem to have light pollution gradients (not surprising in HK) but they show the classic vignette of an image that has not been fully corrected by flats. What processing software are you using? There may be ways to improve the flat correction and remove the light pollution.
  8. I always keep L and RGB as separate channels until I've completed most of my linear processing (background removal, initial noise reduction, etc). I've tried to do background removal and normalisation for RGB as separate channels and as a combined channel and found it easier to do them separately though it does take longer. I found Warren's process flow in his book to be almost ideal. Some of the process steps can be done in different orders but the overall flow works well.
  9. I frequently suffer this bug. Usually during Star alignment. When I searched the PI forums there were similar reports and a suggestion it Had been fixed but I still get it. The only way I avoid it is to manually set the file type and bit depth rather than use the default auto setting.
  10. Really good tracking there with nice round stars almost throughout. I think the target might have benefitted from the longer focal length though I know it's hard to pass over a lens then performs so well!
  11. I don't know how Maxim works but have you checked your not using a setting designed for bias frames?
  12. I hadn't thought to daisy chain my guide camera through the ASI 1600. I found SGPro would sometimes freeze on image downloading on the ASI 1600 and I tracked the cause down to using the an external USB hub into which I'd plugged both cameras. Maybe the hub in the 1600 is much better and I could use that? Anyway, back to your question(s). Why not go down the OAG route? I have the ZWO OAG on my 1600 and filter wheel and it works a charm on the Esprit 80. I always have stars within the OAG field of view and PHD2 is not very fussy about focus/star shapes in the OAG so I don't fuss over getting them spot on! I thought it would be much harder to manage than it was, and using OAG removes a lot of variables.
  13. If you are guiding you shouldn't need PPEC. If the periodic error is so large that guiding does not cope with it then there are bigger issues that need resolving About the only time PPEC would be useful is trying to get longer subs on unguided mounts which suffer from a known periodic error. But why go to all that trouble when guiding is so easy and takes care of all tracking variances, not just PE?
  14. All I can add to the advice above is make sure you test whatever set up you decide to use before you go on your trip. Things that are easy to forget and not easily obtained under dark skies include: A focus mask to go over the front of the scope/lens to help you get sharp focus on stars (works really well for cameras that offer a "live" view that can be zoomed in x5) Adaptors and extenders to join camera to said scope/lens Enough removable storage for the camera so you have enough space to take lots of shorter exposures (if you go down an alt/az route) A decent finder scope if you need to align a goto mount (I found the red dot finders useless, finder scopes much easier and the "live" view through the camera the best once in the right area) Good binoculars so you can enjoy the dark skies while you image A dew shield if you're using the scope and you're going to areas where dew will be an issue Otherwise, keep us posted on the results!
  15. +1 this I don't know about Skywatcher mounts, but the Celestron mounts can polar align using any three stars. It does not need a view of Polaris. It does some wizardry and works out how other stars would move and you adjust your alt/az bolts to centre your chosen star (e.g. something close to meridian).
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