Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

  • Announcements

    sgl_imaging_challenge_banner_widefield.jpg.36065d79cb2625eb299137a5b4432c96.jpg

Astrofriend

Advanced Members
  • Content count

    146
  • Joined

  • Last visited

Community Reputation

79 Excellent

About Astrofriend

  • Rank
    Star Forming

Contact Methods

  • Website URL
    http://astrofriend.eu/

Profile Information

  • Gender
    Male
  • Interests
    Astronomy, Cars, old stuff
  • Location
    Sweden
  1. Time efficiency simulations of three cameras

    Hi Jesper, All telescopes are thought to have focallength that give 1" / pix, see row 18. Then more pixels cover more fov and then less number of images to cover a 100 millions pixels fov, see row 24. It's the same as if had been calculated to cover a degree x degree fov, but it was in this case better to use pixels as a calculation base. I hope you find some use of it. You live in Frence but speak Swedish? /Lars
  2. DIY Big Binoculars mount

    Hi DeepSky Man, Yes I have seen that one, looks to be very well made. I just have one arm and only using it when standing up, it's cold in Sweden at winter. It's a bit limited to 50 degree latitude, but even that will take me some years to investigate :-) Thanks for the link! /Lars
  3. Time efficiency simulations of three cameras

    Hi, Because I don't have all data and it's a bit simpliefied in the calculations you shoud not use this to which camera to buy. If you have more correct data for a particular camera you can overwrite the data in green fields. All cameras are very good. It's more about how to use the camera. If you want to take many short expousures to frezze the seeing you should not have a mechanical shutter. If you have a hot outdoor temperature a uncooled dslr is not the first choise. What's very interesting to see is, if I shorten the exposure, how many more subimages do I need to reach the same S/N for that camera. Or how short exposure must it be to not oversaturate bright objects. How does the iso/gain setting influence the time it takes to reach a given S/N. How does the temperature setting change the S/N, Etc Just test with different input data (red field) and see what you get. That's the main purpose of this excel. And take a look at my homepage if I have done any update of the file since last time. Lars
  4. EQ mount with no meridian flip

    There are more then just the cameras get upside down. If I want to ad a second telescope in future I can't have it on the other side of DEC axis. It will collide with the pier or mount. The Lacerta arm works, but that big one I can't fit in my observatory. Must have it compact! The Avalon is a master piece, but 4000 Euro? I added more drawings about my idea to solve this: http://astrofriend.eu/astronomy/projects/project-eq-mount-with-no-meridian-flip/project-eq-mount-with-no-meridian-flip.html /Lars
  5. EQ mount with no meridian flip

    Hi, Yes they are great mounts, but this have to be a low cost solution. After googled around and with your links I see that I must reuse my EQ6 mount and rebuilt it. But no hurry to solve it, I can use it as it is until I found a solution I like and can manage to do. I'm lucky to live at high latitude and don't have to tilt the arm very much. Thanks for the help! /Lars
  6. EQ mount with no meridian flip

    Now when I have started to use my observatory I face a new problem, meridian flip. Earlier at my balcony I didn't have any problem because I only had a free view to East. Can that problem be solved and still have a German equtorial mount? After have googled on it I found some people who have solved it, not exactly how I want it but close. I have collected my information on my homepage and a first simple drawing how I think will be a good solution for me who live at latitude 59 degrees: http://astrofriend.eu/astronomy/projects/project-eq-mount-with-no-meridian-flip/project-eq-mount-with-no-meridian-flip.html I'm a bit angry at myself that I didn't think about this before I built the pier and observatory, it had been much easier if I had been built it alreday from the beginning. Tell me if you have done any attempt to solve this, maybe better ideas then my own. /Lars
  7. Excel Astronomy calculations

    Over the years I have done a lot of Excel calculation to solve my astronomy problem when I try to make parts work together. Most of them has been my private and only in Swedish, some of them I have published on a Swedish forum and I believe some people have found them useful. Now I decided to translate them into English and put them on my homepage for downloading. It's always hard to understand Excel sheets that others have put together, but I hope that these ones with a little help of the instructions on my homepage could be interesting and useful to some of you. http://astrofriend.eu/astronomy/astronomy-calculations/astronomy-calculations.html Beware that it could be something wrong in the calculations, if I find something I try to correct it. I don't take any responsible of it, you use them at your own risk ! /Lars
  8. Time efficiency simulations of three cameras

    I did an update and included the dark current noise. It could be interesting to compare the uncooled DSLR camera at different temperatures. I'm lucky to live in a cold country with about zero degrees temperature or lower when doing astrophotographing. But if you have about +10 degrees Celcius or more then the thermal noise can be heavy. http://www.astrofriend.eu/astronomy/tutorials/tutorial-camera-time-efficiency/tutorial-camera-time-efficiency.html See at bottom, do a test with different values and see what you get. Note: This are not any precise calculation but give you an overview what happens under different circumstances! /Lars
  9. Hi, When doing color images from DSLR color cameras it could be a bit frustrating to find correct color balance. If you could get to know your DSLR camera's own RGB scaling factors it could be a starting point how to set the scaling factors. With the tool DCRaw you can get these values. Here is a tutorial I have wrote how to use DCRaw to find these values: http://www.astrofriend.eu/astronomy/tutorials/tutorial-rgb-multipliers/tutorial-rgb-multipliers.html I have only use it to my own Canon DSLR, but should work on all cameras that DCRaw support I think. /Lars
  10. Sardinia Observatory visit

    Hi Kevin, Yes it was really a wonderful place, just want to go back to that place now and bring the telescope with me. I think they do observing all year around! I live in wrong country. You must also have hobbies in the summer, Vette is now replaced by a gas saving Crossfire, no place to store the telescope in it :-( Lars
  11. Sardinia Observatory visit

    Hi, My girlfriend and I have just come back from Sardinia island in Italy. One thing we did down there was to visit an amateur observatory. We did didn't plan to do this in advance so we just go up there to see if we could find anyone there. No luck with that but we got a very beautiful view from the summit. Here are a couple of photos from the place: http://www.astrofriend.eu/astronomy/observatory-sites/sardinia-observatory/sardinia-observatory.html What a dream, 1100 meters altitude! There is also a link to the astronomy club, if you plan a visit in advance you maybe will get a chance to have the guided tour, I think they have one every Friday with clear sky. A very nice place, visit it if you are nearby! /Lars
  12. HEQ5 Synscan DEC drifting problem?

    Hi, It will never be perfect, you have the atmosphere that bend the lights at low position near the horizon. That effect is normally included in a goto mount how it should compensate for this. Here is an image that show how it could look with bad polar align and auto guiding: After some hours the object M3 have drift away from its mounts coordinates. It still on target because of the auto guidning but with shifted RA and DEC coordinates. If I order it to go to it's center the mount move it to were it thinks M3 should be, but will not point to M3 anymoore. You can calibrate it to compensate for this but it still will give a rotation of the field and then not possible to do long exposure photos. To get a high precission polar align you can do the drift align method, very easy with computer aid, read here: http://astrofriend.eu/astronomy/tutorials/tutorial-drift-align/tutorial-drift-align.html /Lars
  13. Hi, When boring times comes it could be both fun and interesting to do some calculations. This time I did an Excel sheet over the three cameras: Atik 16200, Canon EOS 6D and ZWO ASI1600. I have the Canon 6D and wanted to see how time efficient it is compare to the others. In the Excel sheet it's possible to setup data for the cameras and object information, light pollution and readout noise and max level that shouldn't saturate (clipp). At the end you see how many sub images it takes to reach a given S/N, Signal / Noise ratio. It also calculate the total exposure time and dead time between images. It only compare pixel to pixel, not that the sensor area or the pixel size is different. Take a look here where I have wrote it down if you find it interesting: http://astrofriend.eu/astronomy/tutorials/tutorial-camera-time-efficiency/tutorial-camera-time-efficiency.html It's very simple so don't expect it to be perfect but you can have a lot of interesting information from it if you test with different parameters. You can download the Excel sheet if you find it interesting. /Lars
  14. These days I have done a Quantum Leap in my progress to have a tool that can give back lost resolution from under sampled images. I tested a plugin that is developed to ImageJ and ImageJ is dedicated to the microscopic world. I didn't think this should work. But cells are a bit galaxy shaped, why not? Plugins to ImageJ should also work in AstroImageJ. I wrote to the developer of Parallel Super-Resolution plugin Piotr. If you find it interesting you can read here what he answered and what I got from my simple test on undersampled M13 images. http://astrofriend.eu/astronomy/tutorials/tutorial-astroimagej-align-drizzle/tutorial-aij-align-parallel-super-resolution.html Impressed? YES! /Lars
  15. I did a new complement in the AIJ macro "Calibrated_object files from CR2 files", a flag that let the flat calibration to be on or off. But the big new is that there is a new macro. The: "Open_DSLR raw files and convert to cfa Tiff 16 bit" (Beta) http://astrofriend.eu/astronomy/tutorials/tutorial-astroimagej/tutorial-aij-03-my-own-macros.html All my three macros are included. With that I hope you can open your files in AstroImageJ whatever DSRL camera you have. If DCRaw can handle the cameras raw file it should work. It opens in batch mode, you don't have to open the files one by one. It opens raw files, and convert to cfa Tiff 16-bit and store under map CFA. I have tested Nikon D3 nef files and Sony A7RII arw files. It looks to work. Note: You must edit the parameter to the filetype in the macro to your specific camera. Let me know if you if you try this with a non Canon camera. /Lars
×