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Merlin66

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Everything posted by Merlin66

  1. The tail of the comet is dust which reflects sunlight. The brighter head (coma) seems to be "glowing" and the Sodium atoms are excited emitting a prominent band at 5890A. There's also emission from the Swan bands between 4440 and 5600A, the CH emission at 4300A is also evident
  2. Hmmm Don’t seem to ship to Australia.......
  3. Don, Thanks for the info, appreciated. (The Meade x3 Tele-extender seems to be no longer available https://www.bhphotovideo.com/c/product/385171-REG/Meade_07676_Series_5000_TeleXtender_3x.html) but the ES model goes on https://agenaastro.com/explore-scientific-3x-focal-extender-barlow-fe03-125.html
  4. In my limited experience, I think there are only two sources of "banding" in solar imaging. The major one is Newton Rings caused by the thin (fixed) cover plate on the sensor chip. This is aggravated by the use of barlows/ powermates. The higher the focal ratio the more difficult the problem. The tried and proven "solution" is the T2 tilter. This effectively changes the sensor glass/ chip gap thereby increasing the gap and reducing NR. I measured some tilts I used....up to 1.4 degrees The other is said to be electronic interference. The USB connection v's local power connections? Don't know exactly as I've never had any real experience. Processing in AS3! and ImPPG/ Registax doesn't appear to cause NR, but I suppose it could enhance the low contrast bands.......
  5. I've been using the Baader Hyperion x2.25 barlow for solar imaging for the past year or so. The screwed T thread fitting is a good feature for me. No issue, no drama.
  6. I had a Meade Series 5000 x3 Tele-extender and then acquired an Explorer Scientific x3 Tele-extender. There were identical. Same physical size, finish and with the same optical elements. Definitely came out of the same Chinese factory.
  7. Have you tried a T2 tilter? I have NR issues with both my ASI 174 and ASI 1600MM.
  8. Is it my screen or do I get some horizontal banding??
  9. Hmmm The Ronchi grating - should show lines and gaps of equal widths.... Check your settings.
  10. Yeah, I posted that some time ago. Photographers generally refer to this data, whereas it’s pretty meaningless to astronomers.. Our interest is in actual chip size, pixel size and QE of the sensor. we need to continue our education of traditional daytime photographers.
  11. Yeah, saw this Ad..... I think the external full sized etalon is a good selling point. Just check out the final selling price ( not the current deposit)
  12. IMHO double stacking the Continuum filter brings limited benefits. There are no defined emission/ absorption features in that region of the spectrum. A polarising filter is always useful to reduce excess light. Note: what ever solar filter system you use must have at least an ND5 reduction (for visual) Some polarising filters still pass some IR wavelengths - best to double check with the supplier.
  13. Old time speak for "Object Glass" = refractor objective lens
  14. I have a spreadsheet I downloaded (from someone - I think on SolarChat) which shows the result of stacking two Gaussian transmission curves. The peak transmission drops and the bandwidth tightens due to the multiplication of the transmission curves. Say if each curve has a peak of 90% transmission, the the combined peak would be (0.9 x 0.9) = 0.81% Likewise if you multiply each point "down the curve" the resultant bandwidth reduces. If each filter is identical, the bandwidth reduction will be around 30%. I'll upload the spreadsheet when I find it. Gausian curve addition.XLS
  15. You've got about three years to save up for the double stack....by then Cycle 25 should have kicked in bringing some sunspots etc. In the meantime enjoy what you have. I have a DS SM60 but at the moment mostly use it SS to view and image the occasional proms. Single stack is much better for the proms, the wider bandwidth suppresses the Doppler shifts. The DS definitely improves surface contrast (when there's something to see )
  16. It’s due to the atmosphere. Differential refraction of the atmosphere, most noticeable when viewing objects at lower altitude, acts like like a prism.
  17. It's pretty well covered in the downloadable Synscan manual. Section 11.4 gives all the details. You can use the "SNAP" port on the mount, or the multi purpose port on the hand controller.
  18. Carole, The online AstroArt Guide (part of the AA7 download) has some basic tutorials to get you started.
  19. Hmmm Don't know, never ever tried it that way....but you do need some means of re-focusing the optical beam emerging from the grating. Any camera (with lens) will work... (This example isn't mine but shows a Ronchi test set-up with compact camera) https://stellafane.org/tm/atm/test/ronchigrams.html http://www.mmresearch.com/articles/article1/
  20. D, I use my Ronchi grating with various cameras and telescopes. My grating has a 1.25” nosepiece which fits to the focuser instead of an eyepiece. without using a camera, set up the grating and look through it at a star.... you should see an out of focus disk with numerous lines across it, use the telescope focuser, the closer the grating gets to focus, the less lines are seen. Its usual to work at a focus which gives around five or six lines visible. The job of the camera plus lens is to replace the eye. Position the camera/ lens combo behind the grating and focus the camera to give clear image of the lines. Hope that helps.
  21. Unfortunately this is the situation. I've had bad experiences in the past with T thread adaptors. Yeah, all M42 x 0.75 threads.......but don't fit each other. I do agree that Baader's strategy seems to work. Never any issues with their threaded gear.
  22. Added to that, I’d recommend starting with the 600 l/mm grating. You can use BASS Project to do all your spectral processing. Any issues/ concerns just let us know.
  23. Just interested in your comment... I use plate solving and just open the wcs.fit image in CdC to display it.... What editing do you have to do??
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