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    Re: Sextants and Glue [was Sisteco Prismatic Compass]
    From: Doug Royer
    Date: 2004 Mar 24, 09:51 -0800

    Outstanding news on your C+P Fred.I also was looking at the moon's cresant
    and Venus for some time last evening.Beautiful wasn't it.Simply stunning at
    least from where I was.
    Is the horizon mirror(and index mirror for that matter)on your Huson the old
    style small mirrors?I'm not familiar with these old British sextants and am
    just curious.What year was it manufactured?Is it a vernier or tangent screw
    type?How "good" are the optics compared with others?Does it have the collar
    that the tube screws into(as in the old David White Mk.IIIs)or does the
    optic assembly fit into a screw on the frame?
    Just curious.
    
    -----Original Message-----
    From: Navigation Mailing List
    [mailto:NAVIGATION-L{at}LISTSERV.WEBKAHUNA.COM]On Behalf Of Fred Hebard
    Sent: Tuesday, March 23, 2004 20:03
    To: NAVIGATION-L{at}LISTSERV.WEBKAHUNA.COM
    Subject: Re: Sextants and Glue [was Sisteco Prismatic Compass]
    
    
    Well, the old C+P I got might be an OK instrument!  I took two sights
    tonight, of Jupiter & Sirius and Ho-Hc for three replications of each
    was 0.042896+/-0.308899, and -0.07455+/-0.212369, where the error
    figure is the square root of the mean of (Ho-Hc) squared; since Hc is a
    parametric mean, the degrees of freedom should equal the number of
    replications.  I've never gotten so close previously, although the
    standard deviations leave a bit to be desired.  Ten to thirty more
    shots and I might get a fair idea of how good this sextant is.
    
    I was driving west and north for a few hundred miles this evening and
    the new moon was hanging about 15-20 degrees underneath Venus.  It was
    perfectly clear and still and would have been a beautiful lunar, easy
    to shoot.   Of course when I got home, the low western sky had clouded
    over.
    
    I have a fair amount of data for my Husun now, which I may get a chance
    to share with the list.  It appears to need about 25 seconds of arc
    added to the existing corrections, although there's some additional
    periodicity in the errors which I don't know how to handle, having
    never fit such data.  I still need to get a chance to fool around a bit
    with the data first.  It would help also if I broke down and got the
    Husun's horizon mirror resilvered.
    
    
    

       
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