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Everything posted by rubecula

  1. Steve, When you determining your filter offsets using a BM did you take any account of the temperature at the time?
  2. That's amazing, I love the star dust.
  3. Thanks Carole & vlaiv. Forcast is for clear skies tonight so I'll try 20 x 600 for L and 10 x 300 for RG&B
  4. Excellent result for a first stab. I wish mine had been as good, also with the 7D. You obviously understand the way to go so I'm sure your results will improve rapidly.
  5. So far I've been taking all images at 600sec binned 1x1. For NB targets I've recently gone out to 1200sec exposures. We get so few clear nights here in England that I'm wondering if I'm not making best use of the time available when it comes to LRGB imaging. Say I took 20 x 600sec luminance binned 1x1, what would be the appropriate settings for RGB frames? Thanks
  6. By pure chance I found the answer on the Tips and Tricks Forum: Meteoblue.com. I'd never heard of it before but it gives arcsec seeing values that cover where I live.
  7. Despite getting a focus motor I've been struggling recently to get decent focus. I'm getting some good help with that from people on the SGP forum. But with all the recent bad weather we've been having in the UK recently I began to wonder if the problem is bad focusing or bad seeing. Is there any independant way of evaluating the seeing conditions without relying on HFR values from SGP? Thanks,
  8. Thanks Adam, based on the above I intend to use both dithering and darks.
  9. Fabulous image. I'm surprised with the SII, I didn't realise any object had that much SII.
  10. Thanks guys, I'll continue to dither and I'm also glad I didn't waste a day capturing 1200s darks.
  11. Are dithering and using darks counterproductive? So far all my CCD imaging has been based on 600s image with a small dither every alternate frame and calibrated with Darks, Flats and Bias frames. I've just been getting some 1200s darks and wondered if you dither then the small movement means that the noise in the light won't match up with the noise in the dark. In which case is it worth using dither and darks? I'm imaging at a focal lenght of 1400mm. Recent calibration has been done in APP. If you only did one which would be the best? Thanks
  12. I'm using the Atik 383L. It maybe belts and braces but I use darks and have PHD2 do a small dither every alternate frame. I hink the mount would cope well with say 1200 but I'm worried about SGP aborting an image when clouds appear. At least tonight I hadn't started imaging. The forecast was for clear sky but just as plate solve had centred on the target the clouds rolled in. It's still cloudy now despite the forecast!
  13. I've been using my current calibration frames for the last 12 months and was thinking perhaps I should refresh them. For that time I have been imaging at -20C with exposures of 600sec. Many of you seem to use much longer subs and as the mount seems to track well I was wondering if I should change to say 900s, 1200s or even 1800s. Also whether I should move to a lower temperature. What's really detering me from going to longer subs is the frustration of when a sub has been running for 500+ secs and a bit of cloud comes over and SGP abandons the image thus loosing nearly 10 minutes of clear sky. I guess loosing nearly 1800s would be 3 times as frustrating. Maybe this is a question for those living above 51 degrees lat, would you, or do you, use longer subs? Thanks
  14. I'm convinced, finally succumbed and bought a copy. Good luck with the Helmet Danny. I tried to get some more data the other day but the seeing was dreadful so had to delete 8 subs as they would probebly have made things worse.
  15. I know there are much, much better images of Thor's Helmet, but I'm quite chuffed with this one. It's so low down in the murk that between the observatory cill and neighbours roofs I only get 1.5hrs a night on it. This is a HOO image from 14 x 600sec Ha and 19 x 600 sec OIII, a total of 6.5 hrs. I took the two sets of subs through APP steps 1 to 6 and then moved them unstretched to PS for further processing. I'm coming round to APP even though it seems a bit pricey for "just" stacking. I've got two weeks left of the trial period to go!
  16. +1 for Thor's Helmet. I imaged that for the first time last night and was surprised how much OIII there is. It's very low down so from my position with houses and trees I don't get much time on it. Here's a completely unprocessed sub from last night:
  17. "was the first image just a direct stack in APP using RGB combine ?" Correct Lee. This is a HOO image so I've put the OIII data into both the green and blue channels. After the RGB combine I tried several ways using the controls on the right (don't really understand what they are supposed to do) and the HSL selective colour but to no avail. I'll try taking the individual stacks into PS and see what I can do.
  18. I've had a play with APP to see if I should purchase. So far I'm not convinced. The first image is my best effort so far with APP. I know it needs cropping and there's a row of cold (?) pixels that I thought outlier rejejection would remove. Otherwise it looks rather dull and star colours are way off. The second image is exactly the same data developed with DSS and PS. I've more experience with DSS and PS but am surprised I can't do better with APP. The lack of documentation doesn't help. I suppose I could move the APP image to PS or Lightroom and improve it but have any of you got better results from APP alone? Thanks
  19. Thanks Adam, I'm not sure what you mean by normalise. Other than DSS and PS the only other software used on the image was Gradient Exterminator that was run on the stretched images. I'll try calibrating a single sub to see what happens. I was also going to download a trial copy of APP to see how it compares to DSS/PS. Is there any particular file structure required for APP?
  20. Very perceptive CloudMagnet. I did use flats, but here is a highly stretched raw sub with nothing else done to it and there's no sign of the dark areas. So it's a processing artifact. Now to find out how it got there. Thanks
  21. I was inspired to have a go at the Wizard thanks to this wonderful image by MartinB: https://stargazerslounge.com/topic/299571-the-wizard-nebula-ngc-7380-in-bicolour/ My effort is an HOO image made from 15 x 600 sec for both Ha and OIII using an Atik 383L on an 8" Celestron Edge HD. I used DSS and then Steve Canestra's method for developing the image in PS. I've been fiddling with it on and off for days and now think this is the best I can do. I suppose that getting more data and better focussing might enable me to do better. I've been struggling with getting good narrowband focusing with a Celestron motor focuser and SGP. Anyway, here it is: But what's foxed me is the dark areas around some (but not all) of the brighter stars. It shows better in this stretched stack of the OIII data: Any idea what could be causing this? Thanks
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