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han59

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Everything posted by han59

  1. You better solve the tilt in X (between left and right). That reduces the quality. Most likely the stars are on one side a little larger. Assuming the average FWHM is about 10, the difference is 2.9/10 is 29% Sometimes just remove and replace the camera could help. Or turn it 180 degrees and look to the difference. Han
  2. You probably are better off by stretching in APP or ASTAP. In GIMP you could stretch using curves, but most likely like in Photoshop you will loose colour of the faint objects: See e.g.: http://allthesky.com/articles/colorpreserve.html or here https://www.markshelley.co.uk/Astronomy/Processing/Colour_Preserving_Stretch/colour_preserving_stretch.html And explained in this little graph: Input: blue=5 red=10 The input colour ratio is then 10/2 is 2. The curve gives these values after stretching: Output: blue=0.26 red= 0.38 De output colour ratio is then 0.38/0.26, about 1.5. De result is less colorful. A better method is colour preserved stretching as implemented in ASTAP: in de range of 0..1: luminance:=(red+green+blue)/3 luminance_stretched:=gamma_curve(luminance) red_output :=luminance_stretched * red greenn_output:=luminance_stretched * green blue_output:=luminance_stretched * blue The ratio between red, green and blue so the colour stays the same. Only the luminance is stretched. Han
  3. Just as a test, screenshot solved in nova.astrometry.net, annotation in ASTAP: Han
  4. Syncing near Polaris could be rejected by EQMOD/HEQ5/6. A small offset will result in a huge RA offset. If the offset is too large, the mount will refuse to sync. You better slew first to an east, south, west or zenith location before you try to sync the mount. Han
  5. I wasn't aware of the X-Trans CFA pattern, but this post triggered me to add experimental X-Trans support to ASTAP (v0.9.351). Maybe useful for Fujifilm camera owners. Han
  6. This difference can be explained If the image is vertical flipped somewhere in the process. There are only four Bayer patterns possible so it doesn't matter so much: Normally RGGB: R G G B Vertical flipped GBRG: G B R G For correct colours, use ASTAP auto colour correction. See tab Stack method "Auto Level and colour smooth" or after stacking go to tab pixel math 1 "Colour correction". It will adjust R, G, B such that background is gray and average star colour is white. But it looks like you already have a nice image. Han p.s. why is this UK site suggesting to change colour to the American color?
  7. Would it help to have a program to convert batchwise all available FITS files to 16 or 32 bit TIFF? No loss of quality. Then there is no need for a plugin. All stack programs can export to TIFF or PNG so the need for Photoshop to read FITS files only exists if you want to stack with Photoshop. Han
  8. Automation makes it possible to use any brief clear sky moment. Imaging an object is not restricted to a single night. You could have 90 minutes of clear sky, take a series of images and continue imaging the same object next clear night. My only setbacks are occasional bad USB connection and computer freeze. The computer freeze is mainly caused by the memory module connector of my old 2009 desktop. The old desktop is permanently placed in my astro shed. It was never designed for the cold and occasional high humidity environment with continuous ventilation. But it has survived already 5 year in the shed. Making the connection a few times normally fixes the problem. One of the two old harddisk doesn't like temperatures below zero so it is used as secondary disk. Han
  9. Thanks again Don. The new ASTAP version 3.19 with asteroid annotation is available to play with. Han
  10. Hello Don, The last image is also fine for me. The two are spot on. Thanks again for providing. I have now enough images for testing and can finish the interface. Will be released in one or two days. Han
  11. No binned 2x2 is fine. Yes please some more for testing. No need for applying darks or flats. It is very stormy here but the sky is now partly clear. But very risky with my flap-open roof. And still some rain is coming.... Han
  12. Now it becomes clear, CCDstack has modified the DATE in the header. The comments by CCDCiel are removed by CCDStack. Okay no problem. Always use DATE-OBS Han
  13. Hello Don, This one matches also well. Took some time to prove but looks all good! I'm only a little puzzled by the two dates in the FITS header: DATE = '2020-02-11T19:45:42' DATE-OBS= '2020-02-11T19:10:42' What is the Windows file time of the original file? Thanks for providing the image! Han
  14. First the one of Michael. This are the result I get at 17:32 UTC and 20:37 UTC. Looks very good. Thanks! Magnitude is 13.1: UTC 17:32 UTC 20:37:
  15. Hello Don, More then 3 month back will most likely give a too large offset. The program uses the MPCORB.dat file from the minor planet center. Unfortunately you can only download the latest MPCORB.dat version, not one from 3 months ago. My intention is to check the rather complex calculation. The annotation should be spot on. You can just load a FITS file (or raw) in the program (astap) , press solve button, press annotate asteroids en it should work. The UTC observation time and location on Earth is read from the FITS header or has to be entered manually. Yes a new image Vesta or Metis will do. If you can make a second one some time later then the movement will prove which object is an asteroid. Han
  16. For the testing new software to annotate asteroids on images, I'm looking for recent images containing asteroid(s) tracks. Preferably in FITS format (with start exposure date) or with the original file time. Is there anybody who can assist? Han
  17. Thanks for the feedback. I'm just waiting for a Sun spot & clear day for further testing. Han
  18. Yes it will work with any camera including OSC sensors as found in a DSLR. The basic principle it pretty simple. It analyses the image on higher frequencies. How sharper the image the more higher frequencies (faster changes in grey) can be found. For practical reasons the focus curve is displayed upside down to make it compatible with a V-curve based on HFD or FWHM. By default the algorithm groups the pixels in 2x2 so a bayer matrix as found in OSC doesn't have any influence. Han
  19. Today I have uploaded on Youtube a live demonstration of autofocus on the Moon: https://youtu.be/8eWxTQTmYBk Han
  20. That could be an option but will require some significant amount of work. Interface should be INDI. There is already an existing INDI sky simulator using the GSC star catalog, but I have never tried it. Is there something to improve? Note that I just fixed a small problem with the "go default" button and it is just uploaded as Sky simulator 1.9. Han
  21. FYI, the ASCOM Sky simulator version 1.8 has been released. The default star database goes now up to magnitude 14. Improved artificial stars. Deepsky labels can be switched off. The image dimensions are now set at one place in the program. Han
  22. Doesn't help you but note that the free alternative GIMP can read FITS file. Han
  23. It is possible to plot in an spreadsheet both the measured V-curve and the hyperbola fit as found: Here an early report of my setup 13:22:39 median Focus=35972 a=1,23909 b=143,37264 _____________ lowest error=0,01187 iteration_cycles=4 13:22:39 center Focus=35925 a=1,87688 b=212,46136 _____________ lowest error=0,00540 iteration_cycles=4 13:22:39 outer ring Focus=36028 a=0,30912 b= 37,90557 offset= 103 lowest error=0,02590 iteration_cycles=6 13:22:39 bottom left Focus=36000 a=1,47225 b=169,40969 offset= 75 lowest error=0,01023 iteration_cycles=2 13:22:39 bottom right Focus=35825 a=1,52325 b=167,86880 offset= -100 lowest error=0,00695 iteration_cycles=2 13:22:40 top left Focus=36094 a=1,39523 b=159,90826 offset= 169 lowest error=0,00958 iteration_cycles=4 13:22:40 top right Focus=35934 a=1,74906 b=200,38594 offset= 9 lowest error=0,00777 iteration_cycles=4 My focuser makes about 1500 steps per mm, so the found differences up to 169 steps are very small a little more then 0.1 mm or 0.004 inch. The measured curve and the hyperbola fit of the INNER area The measured curve and the hyperbola fit of the OUTER area: The spreadsheet used is attached hfd_center.zip
  24. With this post, I want to introduce a new method for measuring tilt and curvature and it is a request for some test data. Thanks, Han The program CCDinspecter measures the tilt and curvature by the difference in FHWM (~hfd) values between the center and outer areas of an image. I have tried to indicate it in a sketch below: I assume CCDinspecter calculates the curvature by ((A/B)-1)*100%. Where B is the average fwhm/hfd of the center and A of the outer areas. This will not work if the image is not in focus. There is even a focuser position where A=B. It would be better if the curvature would be measured as C expressed in focuser steps. So ideally you should measure the best focus position for each area. This can be realised by taking several images like for focusing and find the best focus point of each image area by curve fitting the V-curve of the hfd values measured in each area of the images. This idea is implemented in the free program ASTAP, tab "inspector". You can feed it with several images at different focus points and it will report the best focus point for each area of the image. It is also possible to copy paste the data into a spreadsheet. Then you create graphs like these: Graph of the focus curves of 100mm APO astrograph, focal length 580 mm. Plotted are hfd values of median=all, the center of the image, outer area and the image split in four parts: In the program, the data is presented as a table which can be selected and copied to the clipboard: The usage is as follows: Prepare a series of short exposure images with different focuser positions and a lot of stars. Exposure time a few seconds. Move for each image the focuser a small step but only in one way to prevent backlash problems. Images with stars having an hfd above 12-14 will not be analysed correctly since this was historically not implemented. Browse with ASTAP to the images. Press analyse Optional: Select all rows by ctrl+a, copy with ctrl+c and copy to your favorite spreadsheet. Press curve fitting for report on best focus point for each image area. This is experimental. I'm interested in more test images. If anybody can assist, make them as indicated below. Han
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