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    Re: star-to-star distances
    From: Alexandre Eremenko
    Date: 2004 Sep 30, 08:26 -0500

    Dear Fred,
    Here is one more observation I made yesterday:
    Sept 29 GMT 21:33 Sun, Davis art horizon (with water,
    perfect weather) , Galileo scope:
    8 observations in approx 1 minute intervals. Altitude approx 12 deg.
    Average deviation (of corrected alt from the computed one) 0.2'
    0.0', 0.4', 0.0', 0.4', 0.1', 0.0', -0.2, -0.1'.
    > One quibble, the inverting scope probably is not 7x30.
    Yes, 7 is the magnification, and 30 (milimeters) is its diameter.
    This is what the manual says, and I also measured the diameter
    of the objective lens with a ruler.
    Is not 30 mm a sort of standard diameter for a modern 6x scope?
    (I understand the modern ones are prizmatic, and the old
    6x and 7x scopes look much thinner on the pictures, but nevertheless,
    my scope is 7x30 and non-prizmatic).
    > The reason the Galilean scope is preferred for
    > star _altitudes_ is that
    > it probably has a much larger objective than the inverting scope.
    Yes, it is 4x40, that is 40mm diameter, like the standard
    Cassens-Plath scope. They say these scopes are interchangable
    between Cassens-Plath and SNO-T. I would be very curious to compare
    the quality of the Russian made one with Cassens-Plath.
    > Hopefully, I will acquire a good 7x scope
    > before long and be able to do
    > better with stars and lunars.
    You mean a Russian one? I have not seen them sold separately.
    As I said several times, initially I was somewhat puzzled
    with it, it looked like something of very poor quality.
    My last observations with it, however indicate that it might
    be good.
    I want to show it to a professional in optics/astronomy,
    cannot find one
    in West Lafayette.

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