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gnomus

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Everything posted by gnomus

  1. That’s as maybe, but haven’t you guys heard of dithering?
  2. Ah. Must have missed that. Apologies for the redundancy
  3. Hi Sara I would take a look at the Talon roof controllers - http://observatoriosspag.es/ This is what they use at e-EyE. We have not had the chance to use it yet, but it seems fairly straightwforward.
  4. OK. I worried about the oil, but if the man says it is OK I guess it is OK. Do you ned to use an ERF?
  5. It’s great, Steve. What scope is this?
  6. I don’t really know, but I wonder if ‘colder the better’ (which has face validity) is offset somewhat by having the cooler running at what we scientists call ‘full tilt boogie’.
  7. Hi Tomato. Where are you getting strawberries this time of year? Minus 30 seems a little extreme! Most folk I know aim for around -20. What about doing them in a garage? Or, better yet, isn't your wine cellar reasonably cool? I don't know what camera you have - I would be a little reluctant to stick any of mine in the fridge (even the cheap ones). But I am all for experimentation. If you do plan on putting it in a fridge, I would be tempted to place it inside a freezer bag (or two) to stop any damage from spillages and such like.
  8. Jings - it works. Will you damn well hurry up and finish that book, Steve? We lesser mortals need all the help we can get! Thanks again.
  9. Thanks Steve I'll give it a go. Not sure why you have me down as a PI Puritan. I'm really quite offended !!!
  10. Hi Steve A quick question about the processing - if you're prepared to reveal some of your secrets that is.... I have had a go at emulating this image (blatant copying, in fact) using my Esprit 120/QSI690 combo. I have nowhere near as many subs as yourself - only 3hrs 40 mins each of Ha and OIII. I put it together quickly this morning - just to check on progress - and it seems that no matter what I do the OIII absolutely swamps the Ha. Did you find this? Is that why you shot nearly twice as much Ha as OIII (or would that make no difference)? Steve
  11. Now that I see it on my big monitor (rather than iPad) then I can see that Olly is right. In Photoshop a randomly chosen bit of your background reads: R22: G12: B12.
  12. Colour balance is more pleasing in V2 and the background is much better - to these eyes, anyway.
  13. Great work (as ever), John.
  14. I believe that if you log onto the section (eg #6 Narrowband DSO) the first post in the thread are the 'rules' for that particular challenge. I just had a quick look after reading this thread - and then I submitted a couple of images. I assume you can submit as many as you like? Please let me know if I have made a mistake....
  15. The master flat I have shown you is what happens when you stretch any flat using using the STF tool in PI. Mine look awful too. Since, when shooting a flat, the CCD is presented with an even illumination, when you try to 'stretch ' this (like PI's STF does) there is a gross exaggeration of any minor fluctuation of contrast, and this could lead you to think mistakenly that something is amiss. Without the PI artificial stretch, your flat looks a uniform grey: If there was something wrong with the CCD that my calibration was fixing, then there is no reason why your calibration shouldn't fix it either. I did nothing special or unusual and I did no processing other than a mild stretch. I think it is incorrect to say that I 'fixed' the banding, since I didn't find any banding. My view is that there is nothing wrong with your CCD, your flats, your darks, your biases or your lights. If you recall my earlier post, however, your master flat (generated by DSS) produced issues when your sub was calibrated with it in PI. My guess, therefore, is that DSS is doing something odd when creating the master flat. As I have said before, I cannot help with DSS.
  16. And a quick stretch (I will post the full size greyscale image - so click to expand) - again I see no real issues. Indeed your data seems quite good to me:
  17. Incidentally, if you want the full size stacked FITS file to examine at your leisure, I can leave it up here for a few days: https://www.dropbox.com/s/z5u1wi1ehwetnj8/Midnight_Ha.fits?dl=0 My Dropbox is awfully full though, so I may have to clear it out in the not too distant future.
  18. Hi Jon [For others reading the thread, Jon sent me 5 x Bias frames, 4 x Darks, 4 x T-Shirt Flats and 3 x Ha Lights.] I calibrated, registered and stacked your three subs using APP. The Ha subs were calibrated using a Master Flat, a Master Bias, a Master Dark (all generated from the files you sent me). In addition they have been calibrated with a bad pixel map, again generated from the files (Darks and Flats) you sent me. From loading the files to getting the final stack took only 2-3 of minutes. The flat (which you labelled T-Shirt flat, so I assume that's how you did them) looks identical to that we have seen before from your Lum panel (so it would seem there is nothing amiss with your panel): The calibrated, registered and stacked lights look like this: I have looked as hard as I can for any issues. I even did one of these 'boosted' Screen Transfer Function autostretches in PI: The stack looks absolutely fine to me. I don't see any evidence of the 'banding' you were getting before, do you? (I did suggest that there may be nothing wrong with the flat - and that is my conclusion based on the above.) With the proper amount of calibration frames and a decent handful of subs, this Ha stack would (presumably) look even better. What are your thoughts? Steve
  19. Thanks again, Martin. As to the 'processing time' - probably best I don't work it out. I haven't added up the cost of all the kit either!
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