Welcome to the NavList Message Boards.


A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Add Images & Files
    Re: Using star-star distances
    From: George Huxtable
    Date: 2008 Sep 24, 09:36 +0100

    Hewitt Schlereth wanted to find parts for his Ebbco plastic sextant, and Ken 
    Gebhart wrote about John Weatherlake, who produced the original Ebbco 
    sextants in his garage at Wargrave, Berkshire, England, ending-
    "Any information you may have, as a countryman of Mr. Weatherlake, will be 
    Well, closer than just a couuntryman, we're only half-an-hour's drive apart 
    (or a passage of two days down the Thames), being in the same county, until 
    they shifted the boundary and moved us from Berkshire into Oxfordshire, . 
    But I've never met him or seen his garage operation.
    Ken has it right, the Ebbco is now the  "Antares" model of Plastimo, a 
    French company; they took it over several years ago. I don't know where they 
    are actually made, now. It's in their catalogue at plastimo.co.uk, listed, 
    curiously, under "Electronic navigation". It  looks just the same as the 
    Ebbco product, but I've  seen one behind a glass window only. Plastimo have 
    several US distributors. I doubt if they will supply bits and pieces, in the 
    way that Ebbco would.
    I've owned a couple of Ebbco micrometer sextants in my time, and even an 
    original Vernier model when I started sailing. Strengths and weaknesses have 
    been listed before on this list and its predecessor, but for new readers, 
    here they are again. They apply to the Ebbco version; the Plastimo Antares 
    may or may not be the same. My present model is around 15 years old.
    Light, and easy to use.
    Stable and reproducible (to a minute or less, I've found). The rack was 
    claimed to be machined into the plastic frame, rather than moulded, and I 
    believe that.
    Claimed to be calibrated to within an arc-minute. That, I've never checked, 
    thoroughly, but have found no reason to doubt it.
    When it's dropped on the cockpit grating, it just bounces. This has been 
    checked (inadvertently) a few times.
    Not very rigid. If you grip the handle over-tightly, you can shift one image 
    (sideways) a bit with respect to the other (it comes back when you release 
    the pressure). It's so light to hold, there's no call for such tight 
    Not being skeleton-construction, as are most metal sextants, there's quite a 
    lot more windage, and you can feel some buffeting in a strong breeze.
    The shades are a weak point. Presumably made as a photo-film sandwich, they 
    can delaminate internally over the years, and then show a split-line where 
    they have done so (though that doesn't seem to result in observable 
    One of the adjusting screws bears on the back of the index mirror through 
    its silvering, and over time leaves a spot on it. Poor design, there.
    Some light can get into the telescope around the edges of the shades, though 
    it's easy to cobble-in a bit of baffling to intercept it.
    The mirrors and field-of-view are small, by modern standards.
    If having dropped it, you then tread on it (as happened to me once when my 
    boat lurched), that sea-boot can end its days!
    You can often find secondhand Ebbcos on the British ebay, at ebay.co.uk  , 
    under "sextant" rather than "sextants", in the range of �10 to �20 (about 
    US$ 20 to 40) There are two up there at present.
    For ordinary altitude navigation (but NOT for lunar distances), I rate the 
    Ebbco as a very practicable tool.
    contact George Huxtable, now at george@hux.me.uk
    (switched from george@huxtable.u-net.com)
    or at +44 1865 820222 (from UK, 01865 820222)
    or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK. 
    Navigation List archive: www.fer3.com/arc
    To post, email NavList@fer3.com
    To unsubscribe, email NavList-unsubscribe@fer3.com

    Browse Files

    Drop Files


    What is NavList?

    Join NavList

    (please, no nicknames or handles)
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.

    Email Settings

    Posting Code:

    Custom Index

    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site