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    Re: Sextant Comparisons
    From: Joel Jacobs
    Date: 2004 Mar 20, 16:07 -0500

    Fred,
    
    Your best bet is a Russian SNO-T sextant. They are very underrated, and have
    most all the features of the preferred brands, and even come in a smaller
    size for convenience. However, most of them are sold with only an
    astronomical scope which presents the image inverted, and IMO are useless
    for CELNAV. Configured with the 7 x scope, you should be able to buy one for
    $250.00 because they are a drudge on the market with out an erect imaging
    scope. You can read about them in detail at:
    
    http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3712084763&category=37971
    &sspagename=STRK%3AMESSE%3AIT&rd=1
    
    They wont meet your standards for good looks, but you can get some black
    wrinkle paint, and make them look as pretty as you like. They are a great
    buy.
    
    Joel Jacobs
    
    
    
    ----- Original Message -----
    From: "Fred Hebard" 
    To: 
    Sent: Saturday, March 20, 2004 12:15 PM
    Subject: Re: Sextant Comparisons
    
    
    > Doug,
    >
    > No, I don't collect older equipment.  I have been trying to acquire a
    > sextant suitable for lunar observations, so I look for sextants with
    > defects on Ebay that might still be serviceable.
    >
    > I have one British Husun that only has the "star scope."  It's a 2.5x
    > power scope.  It's my understanding that a more powerful one would give
    > more precise readings.  I checked this by buying an old Simex-type
    > sextant, which subsequently was sold.  I have been looking for another
    > Husun with the inverting telescope or another instrument.  The Cassens
    > & Plath was the first that came up which was suitable.
    >
    > In comparing the Cassens and Plath to the Husun, I would say, overall,
    > that I prefer the Husun at this time.  It's prettier, with the
    > silver-inlayed arc; this increases my fondness for the instrument.  The
    > black crinkle finish is nicer than the Cassens and Plath's.  All the
    > screws are varnished or painted brass; there's no aluminum to corrode
    > with steel screws or react with the brass or bronze (There's no
    > corrosion on my Cassens and Plath; it doesn't appear ever to have been
    > used for extended periods).
    >
    > The 2.5x scope on the Husun has a very wide field of view, wider than
    > the 4x "star scope" on the Cassens and Plath.  I have seen no optical
    > aberrations in the Husun, while the Cassens and Plath star scope has
    > chromatic aberration, which rather surprised me (reddish fringe on the
    > bottom of the image and bluish fringe on the top).  The aberration
    > makes it more difficult to check index error by measuring the sun's
    > semidiameter.
    >
    > The handle on the Husun is straight up and down.  This makes some
    > lunars easier, whereas the tilted handle on both brands of Plaths,
    > while it makes looking at the horizon easier on the wrist, makes lunars
    > more difficult.  When holding the instrument between shots or while
    > waiting, the Husun is less fatiguing to hold
    >
    > The star scope on the Husun is in close to the horizon mirror.  This
    > centers weight in the instrument, making it less fatiguing to hold.
    > Being close in to the horizon mirror, the smaller mirror does not
    > restrict the field of view of the instrument as much as one might
    > suppose.  I suppose the larger mirrors would be "faster" optically,
    > however.
    >
    > The perceived weight of the two instruments is similar.  I have not
    > actually weighed them.
    >
    > The lamp on the Husun can be swung around to illuminate my wrist band
    > when recording data.  The lamp on the Cassens and Plath is guided to
    > illuminate the scales only, making recording data more difficult.
    >
    > The box on the Husun is significantly smaller than the box on the other
    > instruments.
    >
    > These are my impressions after two days.
    >
    > Fred
    > ------------------------------------------------------------------------
    > Frederick V. Hebard, PhD                      Email: mailto:Fred{at}acf.org
    > Staff Pathologist, Meadowview Research Farms  Web: http://www.acf.org
    > American Chestnut Foundation                  Phone: (276) 944-4631
    > 14005 Glenbrook Ave.                          Fax: (276) 944-0934
    > Meadowview, VA 24361
    >
    > On Mar 19, 2004, at 5:44 PM, Royer, Doug wrote:
    >
    > > By the way,do you collect older sextants?Don't you also have some older
    > > British equipment you wrote about in the past?Just curious.
    
    
    

       
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