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About Merlin66

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    Bright Giant
  • Birthday December 9

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    Spectroscopy, Solar observing,- and my wife!
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    St Leonards, Vic, Australia
  1. Jokes aside, this is a great thread. I've been imaging - cooled cameras, hypered cameras then into DSLR and cooled CCD's for over forty years. I was a little bemused when I started to see members wanting to use a phone camera for astronomy....a sign of the times.... BUT I have to say some of the results being obtained are very good! I reminds me of how amateur astro photos started in the sixties and shows great promise for the future. What about some comments on how to use the phone camera (better/ properly?) - I see they now have special attachment brackets to hold the camera to the eyepiece - are they really any good? How do you hold the camera still and yet have a third hand to press the shutter button? All in all, I'm very impressed with the results and hope to see this thread continue.
  2. Great review! I used the 12" meade on a HD wedge for a few years. It was fitted with both the Meade Crayford and the JMI (mirror move) focuser. I had a dual hand controller (from the MAPUG site design) which worked very well for me. Balancing was an issue, so I replaced the Dec nylon bearings with needle bearings and rigged up independent balancing on the Dec and RA. For spectroscopy it worked very well..... The larger spectroscopes didn't fit behind the forks, so in the end I changed to the C11 on an NEQ6pro. I'd say "when they are good, they are very very good, when they are bad they are a PITA"
  3. Peter, It would be interesting to see the Ronchi results... Over the years I've owned many Meades, 8", 10" and 12", I did find on a couple of occasions when testing "new" s/h Meades that the correction plate was "nipped" - the retaining screws tightened tooooo much. After making the screws finger tight and resting over night I found a dramatic improvement in the Ronchi. May be worth checking....
  4. i don't think there are major problems observing at the equator. There are many successful observers around Singapore..... I think your question is directed to setting up an equatorial at low latitudes.....a modified tripod/ pier will get the elevation down to zero.
  5. I use AA6 to control all my cameras, guiding and acquisition for spectroscopy. AA6 uses flat darks (darks taken at the same exposure as the flats) rather than bias frames. Works very well for me.
  6. The answer is basically yes. If the "basic" mod you are considering is just the removal of the colour balance filter then note that you will not be able to focus standard EF lenses (say for wide angle shots) without adding at least a clear filter element (I use an Astronomik clip in clear screen). No issue when used with a telescope.
  7. Ketut, Unfortunately the D350D data is based on an older single filter element design and not truly representative of the current two filter design. The curves I presented were based on one example tested, others show that the IR drop off is quite significant. Is there any feedback from current users????? (I only use my modded 450D- full spectral mod, both filters removed, for spectroscopy)
  8. My point was that the UV/IR filtering of the modded camera is no different to that in the original camera. The results should therefore be similar. If an additional Uv/IR filter is advocated then it should also be used with the "basic" unmodified camera.
  9. Is it really a problem? The Bayer Matrix filter and the inherent response curve of the sensor is causing the response to tend towards zero in these extreme wavelengths. The total "system" I think needs to be considered. I have confidence in the Canon designers that they ensured that the best balance and response was being achieved. I don't remember seeing any blue bloat or red bloat with the Canon camera... Has anyone got some good before after shots showng an UV/IR problem??
  10. not a real issue, you should be OK with the modded camera.
  11. I have uploaded a few times the transmission curves for both the colour correction filter (filter#2) - the one usually removed to improve the red response and the other front anti-alias/ dust shake filter (filter#1) which acts as an effective UV/IR filter.
  12. Nice images. A tilter in front of the camera will suppress those Newton Rings.....
  13. OK, I have been thinking about this "increased FOV" issue...... Based on the details given in the thread I can now only assume that the bino viewer is also acting as a reducer...this may be due to the spacing and the optics acting as a transfer lens with a positive effect ie the effective focal length is reduced and hence the FOV increased. Does this make any sense??????
  14. Exactly! Larger BF diameters are designed for longer focal length systems to maintain full solar disk coverage, when used on shorter focal length systems, the additional FOV can be useful to ensure large faint proms are well recorded.
  15. Don, As the back focus distance changes so does the focal length of a SCT. This means that the final focal ratio will change. The Wimslow formula did not accurately take this into account.