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lensman57

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Everything posted by lensman57

  1. Hi, Taken last night once I realised that the weather forecast was not accurate. The presence of the bright Moon did not help the proceedings but it is better than nothing. 13 x 900s subs, Atik 428 EXC, Idas D1, WO Star71 all on HEQ5 Pro. Processed in PI and PS. Thanks for looking, A.G
  2. Hi, I am not quite sure if APT dithers with PHD2 as the guide progs that are listed are Stark labs PHD, Meta guide, lacerta mgen and APT guiding. I use PHD and APT dithers flawlessly. Try with PHD rather than PHD2. with auto dither Enabled. A.G
  3. You can bin the RGB ( provided that the imaging scale is up to it ) but then you need unbinned Lum. If the RGB is not binned and with long enough exposure you maybe able to do away with LUM. There is a technique of getting the Synth Lum out of unbinned RGB but I for the love of god can not remember how to it. A.G
  4. Make sure that the shutter us operating correctly as it is mechanical. It should open and close twice upon connection to the laptop. You should also ask to see a Bias and preferably a 900s Dark frame just to make sure that there are no problems with the sensor. The peltier cooling is usually reliable but you would probably have to recharge the desiccant tablets in the oven to be on the safe side otherwise you get icing on the sensor due to rapid cooling. Otherwise 383L should be a reliable work horse. A.G
  5. I can write down the steps for you but as I used Pixinsight I doubt if it relates to anything like Gimp or PS, anyhow here it goes. Apply the Screen Transfer Tool, data is still linear. Applied the Dynamic Background Extraction tool with default settings, data is still linear. Applied the Colour Calibration Tool using masses of stars, Aggregated from previews as the white reference. Reapply the STF tool, data is still linear. Applied the Histogram Transformation tool with STF parameters and lined up the colours, this is like Levels in PS, data is no longer linear. Made a Star Mask to include all the small and medium size stars, applied Convolution to the mask, this is like a gaussian blur in PS. Applied the mask to the stars. Used the the Curves tool increase saturation in the stars. Reapplied the Histogram Tansformation tool. Applied a mild ACDNR noise reduction to the low signal areas, excluding the stars totally. Applied SCNR to remove any traces of the Green, this is like HLVG filter in PS. Applied a mild Morphological Transformation to the stars using the star mask to reduce the size a little, this can also be done in PS using the Minimum filter or using Noel Carboni's actions. Saved as jpeg. Poo...h, it took longer to write all this down than it took to do them. Regards, A.G
  6. To be honest you need a lot more data to make this sing. I have had a quick play and here is the result without pushing it too far out and making a mess. I think Louise and Matt have done a good job of getting the data out and Olly's suggestion is excellent and would give first class results if you employ the appropriate masks. A.G
  7. As you say the process of data collection is almost totally automated and computer dependent. I too find this boring. The thrill for me is finding the targets and the post capture processing. I must also add that I find processing " Mono " images a lot easier than OSC and lot more satisfying for some peculiar reasons. Regards, A.G
  8. Whether you go for OSC or Mono with RGB or NB filters depends to a great deal on your location and your sky. If you are fortunate to have dark skies free of LP, clouds and unpredictable weather as most of us suffer from in the UK then a Mono sensor will be your fastest ticket to very high quality RGB or NB imaging. Life is seldom so kind to us so we have to make the best of what we have. I live in the suburbs of Manchester and the chance of having two or more consecutive clear and dark evenings in the proper astronomical terms are very slim indeed. At the moment I am getting about 2 hours of imaging time about every 18~20 days. This means that all my very expensive RGB and NB filters are just sitting in the box and loosing me interest on the money that I have spent on them. I for one would be the first to say that a Mono CCD with filters would give you much more quality than an OSC sensor with the same total integration time but this is only possible if you are sure that you can get the clear spells to use them , otherwise an OSC camera will give you results even after a short integration time of 2~2.5 Hours. Only you can be the judge as you know your local sky better than anyone else. Regards, A.G
  9. Lovely image. They seem as if they were overhead when you imaged them. A.G
  10. lovely set of images Matt. I too am very envious of the Southern skies. Only wish. A.G
  11. Hi Joe, First of all you have one of the best and quitest modern sensors in your camera that is commercially available. Second, you also have set point cooling. Your sensor is quiet and clean as your post has shown. Sony ICX sensors generally do not need Darks certainly not at any sub length below 300C. I have not used Darks with either my 428 EXC or 314L+. They work at between -10C~ -15C. I don't use Darks even with my 383L+ which is a lot noisier than the ICX ones. I just set it to -20C. You do not need a Dark library for sure. A Dark library maybe useful for DSLR imagers since they do not have set point cooling or often any cooling, therefore for any length of exposure they need a set of Darks thinking that after a exposure of 120s~180s the sensor temperature stabilises which does not. I have posted links to various research and articles stating that unless the temperature of the sensor could be very closely matched Darks taken at one session are not of any use to another, yes you can match the exposure length but not the exact temperature sensor as this has to be within a couple of degrees of C. A camera without active set point cooling can start imaging with the ambient temp @ 5C and end the session when the ambient temp at -3C for example, this often happens during the long winter nights. A temp difference of 8C will render the Darks useless but not with a camera with set point cooling since once set to lets say -15C it will stay @ -15C no matter what the out side temp. What you have to do to is reduce the noise in the stack. Firstly use a lot of subs with dithering and then you get rid of the noise in the low signal areas post process. Regarding calibration frames, the more you take the better. I have master Bias made out of at least100 Bias frames and master Flats made out of 55 Flats. This is so that the master calibration frames would be as clean as possible and not induce any more of their own noise into the process or in another word these master Calibration frames are neutral as far as noise is concerned. If you must use Darks then I suggest that you take 25 @ 300s, 25 @ 600s and 25 @ 900s exposure time all @ - 15C and then use them if you must. You can then compare the result to the one without Darks and judge for your self. Regards, A.G
  12. I am afraid that your statement that a single frame looks better than a stack is incorrect. If you stacked the frames and end up with more noise and not enough signal then something is not right. This is usually caused by incorrect or mismatched calibration frames. I would not bother with the Dark frame first if I were you and just use a large number of Bias and Flat frames to start with and see if the image improves. You should also be merciless with the Lights and examine each frame before putting it in the stack. A single bad Light frame with low signal or misshaped stars will degrade the entire stack. I have attached two small jpegs of the Cocoon nebula taken a few nights ago. One is a single sub and the other is a stack of only 5 subs, these have only had calibration and a stretch with a straight STF parameters applied to them in Pixinsight. I leave it to you to guess which is which. I normally capture at least 10~12 subs and often 16~20 for stacking. I threw away 4 subs from this imaging session since they were ruined by thin passing clouds and had low signal. In theory a single sub will have less noise than a stack but it will have much lower signal so the stack wins. Regards, A.G
  13. Sorry for the double post. I have deleted it. A.G
  14. !2.30 am is a good time to start imaging as the sky doesn't really get dark till 12.00, one of the many benefits of a British summer. A.G
  15. This is very good , well done. With regret Sagittarius is a none starter from my location, it only rises about 12 degrees above horizon at its peak. Regards, A.G
  16. There is noise but relatively for a single frame these are quite clean. Try stacking 16~20 of these and noise level will be dramatically reduced. Try dithering your subs in the capture software for further reduction of noise and if you apply Sigma Clipping during stacking the hot pixels will be taken care of too. Application of Dark Frames may help but since the 414 is quite a clean sensor the mileage you get may vary somewhat. A.G
  17. Hi, Taken early on this morning. Due to my stupidity I wasted over an hour of imaging time because I had forgotten to set the number of subs in NEB. It only took one sub and then stopped, 3 more were discarded due to the cloud cover. This is result of 5 subs of 900s each. I have a funny feeling that there were quite a bit of very thin high clouds anyway. WO Star 71, Atik 428EXC, IDAS D1 and HEQ5. Processed in PI. Thanks for looking . A.G
  18. You must take the Flats at the same ISO as your Light and Bias frames. The first step in processing the stack is the subtraction of Master Bias from the individual Flat frames, these are then stacked to make a Master Flat. If these are not matched in ISO the resulting Master Flat will not be a match to the Lights. ISO setting in a DSLR is nothing but a gain value and by altering the gain the level of the noise is altered. It is best to take all the calibration frames at the same ISO setting so the pedestal noise values match. A.G
  19. Worth waiting for, brilliant capture and subtle processing. A.G
  20. You can take away about 10mm off the draw tube on the safe side and no more. The problem with cutting a little too much off the draw tube is that the spacing of the ball bearings in relation to the draw tube. Cut too much and the most inward bearings loose contact with the tube and it will then flops. To be honest this is bad design on the part of SW and it should really be put right. A.G
  21. You can mark the position of the feet of the mount's legs . once you have a good PA you can then return the mount to the same position as marked and do a hand set PA routine. with the FL of your scope, 480mm , you should be able to get a good enough PA after a couple of cycles of the PA routine to be within or less than one minute of arc. A.G
  22. This is not coma, you need a field flattener with your scope, the one form SW works fine and is cheap. I have also read your post regarding " Terrestrial Polar Alignment ". With all due respect I think this idea is nuts. You can use a Terrestrial object to get the scope in a similar position as when had a good PA but you need to Polar Align it properly even after a visual alignment. You can use your handset PA routine. May I suggest that you invest some time reading up about the basics of imaging first. You could buy the book " Make every photon count " as it is very good book on the subject. Regards, A.G
  23. Nebulosity has very little on line tutorial. I use it more as a capture software and I am very happy with it. It also does a decent job in stacking but the steps are manual so you have control over what goes on. I don't use the image processing section as I already have Star Tools and Pi. If you expect it to be an automated process like DSS then I am afraid you would disappointed. Try this link for a bit more information. https://www.youtube.com/watch?v=OMhLYg-xPuc. Regards. A.G
  24. Flats should be taken at the end of the imaging session without disturbing the orientation of the scope/lens and at the same focus position. Do not alter the ISO this is important . I doubt very much that your present set of flats are a match for you old image of Orion Constellation. A.G
  25. Great image Matt. A bonus on top of good holiday. Regards, A.G
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