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jimthompson

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About jimthompson

  • Rank
    Nebula

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  • Website URL
    http://karmalimbo.com/aro

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  • Gender
    Male
  • Interests
    Aerospace, Astronomy, Evolution
  • Location
    Ottawa, Canada
  1. Hi Roel, I was using a filter in the instance when my attached images were captured, however I get the halo with or without a filter. A year ago when I first brought this problem up I believe Paul said he was aware of it and it had something to do with the debayer algorithm in SLL, but I guess he has not had time to track the issue down. Regards, Jim T.
  2. If it helps to see what is going on better, I've attached the same image but split into the three colour channels RGB. It seems like the RED colour channel saturates sooner than the other two, which results in stars appearing larger in the red channel thus giving them the yellow-red halo. Is it possible to check each pixel for saturation of RGB values, and if one is saturated and the other two aren't or nearly so then replace the saturated colour value with an average or max of the other two or something? This might help reduce visibility of hot pixels also which tend to appear as pure red green or blue pixels.
  3. Hi All, I have not had an opportunity to use my SX cameras much over the past 6-8 months but finally had a chance over the past couple weeks. I have encountered a few issues that I wonder if there is a fix for. #1 Lodestar X2C with SLL 3.3 has green stars. The previous version I used, v2 I think, did not have this issue nor did any of the Lodestar Live versions which is what I ended up using on the night in question. I forgot to record an image showing an example. #2 Ultrastar-C has yellow-red halo around stars. This is an ongoing problem that I have seen for a couple versions of SLL now and I think it has been discussed before. Is there a solution for this issue? I have attached an example image below. Thanks, Jim T.
  4. Yes indeed Martin, nice work! A fun challenge that EAA has succeeded at yet again. cheers, Jim T.
  5. I have put together some image comparisons to try to demonstrate the impact of sharpening tools. I used VirtualDub and its built in Unsharp Mask and Warpsharp tools in particular. I have gone light on the sharpening settings to have a minimum of artifacts but still see a noticeable improvement in the image. A lot more sharpening is possible using these same tools if you don't mind the increase in noise or other artifacts. https://www.flickr.com/photos/abbeyroadobservatory/albums/72157675420188260 I find Warpsharp works well on nebulae as it shrinks the size of stars and smooths out the remaining noise if there is any. This leaves the nebulosity itself more pronounced and easier to see. Unsharp mask works well on scenes already having high contrast such as globular clusters, or on images with low noise (ie. large number of stacked frames). It is tricky to use however and not have noise overly accentuated as well. For very soft (blurry) images, such as what you tend to get when you stack images from a small sensor or at a long focal length, you can apply Warpsharp to tighten everything up then apply Unsharp Mask on top to further enhance detail. For certain sharpening is a matter of personal preference, but I think it is a very important tool to have. cheers, Jim T. p.s. Another SLL improvement that I forgot to mention is fixing the red bleeding artifact around bright stars and yellow image tinge when using the Ultrastar C (see attached image)
  6. I wonder if it is okay to make requests wrt software features? I have a few ideas but don't know how major an effort they would be to implement. 1. User defined gamma: Very early versions of LodestarLive had an extra slider to adjust gamma, but that has since been replaced by the three histogram scaling presets (linear, arcsinh & x^0.25). Although the presets work well, I still miss being able to adjust gamma (or "grey point") manually. On really dim objects it would be nice to push the gamma even more than what the presets allow for. As an example the white/grey/black set point sliders on the histogram in the Infinity software works very nicely. 2. Sharpening tools: I can recall asking about this in the past (I just don't remember who I asked!) but am yet to see it implemented in most EAA software. In the past I have passed my live feed through VirtualDub using its screen capture tool, then applied sharpening filters in VD. I especially like "warpsharp" and "unsharp mask". The warpsharp algorithm is out there in the opensource world. I like it as it tightens up edges and makes stars less bloated, and it reduces the visibility of noise. Unsharp mask is a classic detail enhancement tool that can greatly increase contrast in the image. If not set correctly it will also enhance noise, so it works better on a stacked image with low noise. I will try to generate some example images when I get home from work to show the impact of applying these two filters. Personally I think sharpening would add a great capability for live observing. 3. Zoom in on histogram: When using the current histogram I sometimes find it difficult to see what is going on with the histogram since the whole 16bits of the image is being displayed, resulting in the image data occupying only a small part of the histogram. Is it possible to instead display just the part of the histogram between the white point and black point, or perhaps a little bit on either side of these points? This would in effect zoom in on just the image data that is presently on the screen. Perhaps it could be an option, to choose what scaling to use for the histogram plot? Thank you for considering my ideas. I appreciate your hard work! Best Regards, Jim T.
  7. I have the colour version of the Lodestar X2 and it is plenty sensitive. If you look at the last column on the right of my table above, you can compare the relative sensitivities of the different sensors. The colour ICX829 sensor that is in the Lodestar X2 is at 3200mV sensitivity, compared to 881mV for the IMX224 or 319mV for the IMX178. You can use the CMOS sensored cameras for EAA okay, but in my opinion only on reasonably bright objects (eg. Messier Objects). If you don't want to be limited at all and be able to easily observe the dimmest of objects, a camera with the ICX828/829 sensor is the way to go. cheers, Jim T.
  8. I have used a variety of cameras including the Lodestar C, Lodestar X2C, Ultrastar C, Infinity C, ASI185MC, ASI290MM, and a whole raft of Mallincam models. I very much like the Lodestar X2 as it has probably the best sensitivity out of the bunch. The software is also quite straight forward to use. Regards, Jim T.
  9. Well, considering that the latest sensors are on the order of 2x to 4x the sensitivity, I'd say it is a fairly significant difference. That is just comparing older gen CCD's with newer gen CCD's. If you now add in the latest CMOS sensors then you have a whole line of new cameras with read noise that is much lower than these older CCD based cameras (1 or 2 e- versus 10 to 20 e-). I have been keeping a list that compiles all the sensor data I come across. I have updated it to include the sensors in the Moravian Instruments cameras. Hopefully it helps to give you an idea of the performance differences between the different sensors. Best Regards, Jim T.
  10. Wow, really impressive captures Errol. Well done! I am a huge fan of small refractors in the summertime. IC1318 near Gamma Cygni is one of my favorites...I call it the Dragon Nebula because I think it looks like the head of an oriental dragon. cheers! Jim T.
  11. My only remark is that all of the camera models listed under G0 and G1 type use older generation Sony CCD sensors. For the same price or less you can find cameras on the market with the latest in commercial sensor technology, bringing you superior noise and sensitivity. Regards, Jim T.
  12. Thanks Paul. I am looking forward to having my Lodestar X2 and Ultrastar running simultaneously. cheers, Jim T.
  13. Thanks Paul, the iOS entry in my table is a typo. Regards, Jim T.
  14. Greetings all, Some of you may be aware that I have been picking away at a big project involving the systematic testing and comparison of many EAA cameras. The scope of my project seems to be growing without bound as new camera models are released. In an effort to keep up I have taken a divide and conquer approach, focusing on a subset of cameras at one time. In this case I have been looking specifically at EAA cameras that use the Sony ICX825 sensor: Atik Infinity, StarlightXpress Ultrastar and Mallincam StarVision. I was very fortunate to have friends loan me the cameras needed to do the testing, to them I give a big thank you. Below are links to my summary test report, and a comparison table. Please feel free to have a look and let me know if you have any questions. Best Regards, Jim T. http://karmalimbo.com/aro/reports/Test Report - 825 Sensor Camera Comparison_07Oct2016.pdf http://karmalimbo.com/aro/reports/825 camera comparison table_07Oct2016.pdf
  15. Sorry I am late responding. Paul, in your list of steps above, I only had to save the master dark for the strange behavior to happen. I did not need to read the saved dark back in again. So if I simply acquired the darks (usually 5 to 10) and switched back into image acquisition mode there was no problem, but if I saved the dark after acquiring it things are messed up. It seems to be repeatable. Note I am using the program under Windows 8.1 with my Lodestar X2c. Regards, Jim T.
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