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About Merlin66

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    Bright Giant

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  • Interests
    Spectroscopy, Solar observing,- and my wife!
  • Location
    St Leonards, Vic, Australia
  1. 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
  2. Excellent capture! Well done.
  3. 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.......
  4. 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.
  5. 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.
  6. Have you tried a T2 tilter? I have NR issues with both my ASI 174 and ASI 1600MM.
  7. Is it my screen or do I get some horizontal banding??
  8. Hmmm The Ronchi grating - should show lines and gaps of equal widths.... Check your settings.
  9. 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.
  10. 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)
  11. 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.
  12. Old time speak for "Object Glass" = refractor objective lens
  13. 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
  14. 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 )
  15. It’s due to the atmosphere. Differential refraction of the atmosphere, most noticeable when viewing objects at lower altitude, acts like like a prism.
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