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~ C. Plath Pedigree ~ 5 STARS

Presented is our second
opportunity in about a year to offer an absolutely outstanding and near flawless “Collector Quality” example of a U.S. Navy
MK III sextant. In this case, we present Serial No. 1965 made by Scientific Instruments of Milwaukee, WI. All their MK III
instruments made by them have their tag riveted on the index arm. The sextant comes complete with all
its original accessories including a spare set of mirrors and a sighting circle, and its Butternut wood case. The
matching certificate is dated 1/27/86.
SOME BACKGROUND: At the time the design of this
sextant was adopted around 1975, I was a member of the Navy Department’s Navigation Symposium Board, and remember the criteria
that was established. They coincided with already existing technology in the civilian maritime community. In total, the new
design was far advanced from the ubiquitous Navy WW II standby, the Navy MK II.
The Tamaya MS 733 and the C. Plath sextants met these criteria as
did a few others, but there was strong feelings in government procurement then to “Buy American” in contrast to today’s World
Economy. Consequently, two American manufactures were selected for the MK III program, M. Low of which little is known other
than they were in New York, and Scientific Instruments, of Milwaukee, WI. These sextants were made under license by C.
Plath, Hamburg, Germany who may have provided the tooling. C. Plath aficionados take note, the design is clearly the same
as the C. Plath Classic sextant down to the last detail other than its ergonomic handle and large size high impact resistant
case, and this pedigree is noted on page 119 of the book by Friedrich Jerchow, “From Sextant to Satellite
Navigation, (1837-1987) 150 years C. Plath”.
At last report, this design, was still being issued in very small numbers
on newly built U.S. Navy ships. Today, a new one costs over $4300.00 according to Scientific Instruments which is still in
business. Five years ago I used one with good results when I went on a brief cruise on a Spruance Class destroyer, USS CARON,
DD 970. I appreciated its lighter than average weight, and comfortable handle.
Listed are what were “state of the art” design features, that are still
the standard today:
Light weight
Large size index mirror
Large size horizon mirror
Lighting system
Vernier reading to 6 seconds
Handle for ergonomic fit
Wide angle telescope
Non adjustable instrument error of less than 20 arc seconds
Military high impact absorbent case

CONDITION: The sextant shows little discernable evidence of wear or use so that it can be considered as near new in all respects. All its
machinery works well. Both fitted mirrors show as NEW. It comes with a set of replacement mirrors. The numbers match
on the certificate. The lighting works. The nicely finished Butternut case shows it has served
at sea and has a few scratches on its top. There are also some minor dents and slight scratches.The index error is negligible,
and there is a touch of side error which is a good thing. The last certificate is included. No locks are fitted to this Navy
style case.
STAR RANKING: This sextant and case rates
This is fine sextant is in perfect condition and is backed by our guarantee of satisfaction. It requires
someone who can appreciate the fine points of a sextant, and is willing to pay an appropriate price for this level of quality
and excellence.
DOES MY OPINION COUNT: We are one of the few company’s still selling navigation instruments that know anything about them. For purposes of judging
whether my opinion counts, I was the editor of the chapter on sextants of the 1977 Edition of “Bowditch”, The American
Practical Navigator, NAVPUB 9; a member of the U.S. Naval Academy Navigation Symposium Board, 1975 -1978; the author of a
book on marine sextants, Cornell Maritime Press,1975, and the founding president of Nautech Maritime Corporation which partnered
with Tamaya of Japan in the introduction of the MS 733 Spica, the MS 833, Jupiter, MS 933 Venus sextants and the famous NC-2
navigation computer, in the U.S. market. I also am a retired Master Mariner, and held a U.S. Navy “D” Qualification
as a Senior Skipper – Oceans. From 1995 until 2001, I served as a Varsity Offshore Coach at the U.S. Naval Academy.

Measuring Range: -5 to 125 degrees
Accuracy: Tested to +/- 20 arc seconds
Telescope: 2 x 40 Coated optics
Frame: Aluminum with black enamel paint and white
Micrometer Drum and Vernier Scale: reads to 6 arc seconds
Index Mirror: 57 x 42 mm with spare
Horizon Mirror: 57mm diameter with spare
3 for index mirror
for horizon mirror

Weight sextant: 2.5 lbs, Weight case in case 12.5 lbs.


1 Sextant frame
1 2 x 40 Scope
1 Mirror adjustment tool
2 Spare mirrors
1 Brush
1 Mahogany sextant case. No locks
1 Certificate dated 1986

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Shipping & Packaging

The cost of shipping, packing, handling, and insurance to your destination, will be calculated point to point and is an additional charge. You may email us to get these costs. We price our shipping honestly, but we expect to be reimbursed for the nominal cost of packaging materials and handling.

Our Unconditional 'No Nonsense' Guarantee

If not completely satisfied with your purchase it may be returned, if without damage, within three days of receipt in its original packaging. Return items must be insured for their full value. Only a prior email authorization by us for the return is required. Shipping charges are refundable if due to our error within the continental United States.

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Celebrating 18 Years of Exellence in Nautical Antiques

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