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    Re: Dream Choice of Sextant
    From: Robert Eno
    Date: 2005 Aug 8, 07:39 -0400

    I know my choice lies outside the bounds of what you described but my dream
    choice of sextant would be a C.Plath design in which all of the components
    are constructed from 316 stainless steel. I often wonder why no one ever
    thought of using this material for a sextant. Perhaps because it cannot be
    cast or perhaps because stainless steel is more prone to thermal changes
    than bronze or brass.
    ----- Original Message -----
    From: "Mike Hannibal" 
    Sent: Monday, August 08, 2005 2:43 AM
    Subject: Dream Choice of Sextant
    > If you had a choice between a C&P Horizon Ultra and a
    > C&P Pelorus which would you choose? Money isn't the
    > issue.
    > The use is the full breadth of uses to which you might
    > put a sextant with an equal balance between
    > star/planet sights, sun sights and coastal nav stuff -
    > distance off, horizontal bearing etc.
    > For those unfamiliar the key differences between the
    > two instruments are:
    > 1) both use the same frame and "running gear";
    > 2) the Horizon Ultra has a whole horizon mirror,
    > polarisers in both sets of shade glasses and
    > Schueler's double prism to get verticality right. In
    > other words it's a specialist sun machine;
    > 3) the Pelorus has standard shades, an astigmatiser
    > for stars and planets, and an unusual horizon mirror
    > that is about 70% silvered in the a centre vertical
    > strip and unsilvered on either side. It is designed to
    > be very effective with dim stars but still OK brighter
    > objects.
    > I guess my current thinking is that the polarisers are
    > nice and make sun brightness and horizon clarity very
    > easy to get just right but that the Polaris is
    > proabably better for stars as it isn't hampered by the
    > known issues of a whole horizon mirror. On balance
    > what I want is the Pelorus with the polarisers as
    > well. I expect that verticality of the instrument will
    > not be an issue when using the astigmatiser but that
    > you'll just have to rock like you always do when doing
    > sun/moon.
    > Love to hear your views, and particularly if anyone
    > has used the Polaris or the Horizon Ultra.
    > Regards
    > Pelorus
    > Send instant messages to your online friends http://au.messenger.yahoo.com

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