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Posts posted by Merlin66

  1. Yes, a PC with a bit of grunt helps....

    I use AS! to process my solar videos, the attached screens shows my settings.

    Decide when viewing the quality graph which quality level/ number of frames you want to stack. select an AP size (I use 48 for full frames and 24 for ROI).

    click "Place the AP grid", and Stack......

    Notice I also click the sharpening button - this gives a good first approximation of what minimal tweaking might achieve -  a good guide and starting point.

    Use ImPPG to do the final "improvements".






  2. I use three ED80 scopes and a Genesis.....

    I feel uncomfortable (!!) after being so impressed with the Petzval design Genesis for so many years to admit that the performance of the ED80 is very (very) good.

    I would recommend the ED80 scopes to any amateur. Bang per buck they can’t be beat.


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  3. Back to basics....

    Amateur Telescope Making, Volume 2, p623-647

    The definition of the RTF = Richest-Field Telescope (note - not just a rich field telescope)

    to quote: "....every aperture could be made "a" RFT of that aperture, for a given observer and that there was one of all these which, in connection with the curve of star density against magnitude of stars, was uniquely "the" RFT for the observer, in respect to the maximum countable number of stars per apparent square degree"

    Note there's no real mention of field of view, just the maximum stars per square degree.

    Based on the subsequent tables (p624/5)

    a "real" RTF of 10" aperture at x33.9 would give a FOV approx 1.5 degree and show 306,000 stars per square degree down to 14 mag.

    These figures were based on the available eyepieces at the time, AFOV 40 degree, and a rich galactic star field being observed.

    It is also based on a dark adapted eye accepting a maximum of 7.5mm exit pupil.


    The Borg 67mm is close to 2.5" aperture....

    The ATM table (p624) gives:

    Limiting magnitude 11

    Magnification x8.5

    Total stars per sq. degree 25,400



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