Davis Mark 15 Plastic Sextant

All plastic sextants are inspected at Starpath before shipping.

$379.00   ...item# 1840d15

Davis Mark 15 Plastic Sextant.
This product when purchased here includes a complimentary copy of

How to Use Plastic Sextants—with Applications to Metal Sextants and a Review of Sextant Piloting by David Burch.

This model has many features of traditional sextants including 7 large sunshades, telescope (3 x 27), and micrometer drum vernier scale that reads to 0.2'. The Mark 15 has a standard 7" (18 cm) frame radius graduated from 120° to -5° and comes with a traditional half-silvered mirror. Two sight tubes included have no practical application.

It comes with good instruction booklet. All replacement parts (even the screws!) are readily available. Well cared for, this instrument will last a life time, and you could indeed circumnavigate the globe with this device as your guide — and our included booklet on how to use it.

Referring to content in How to Use Plastic Sextants, you will see that this instrument can be used with care and good procedures to obtain accuracy of a few miles (3 to 5). This is in fact the same accuracy you would get from a metal sextant if not used with best procedures.

The procedures required to optimize plastic sextant accuracy are more involved than those for using a metal sextant, but the actual physical sight taking itself is actually easier with the plastic instrument because they are so much lighter in weight. Also, these instruments are more than accurate enough for piloting fixes in coastal navigation (using horizontal sextant angles) and for this application they might even be considered superior to metal sextants with regard to ease of use. Out textbook explains the procedures.

The Mark 15 does not have lighted dials, but a simple dim light on a lanyard solves that problem, if not even better than built in sextant lights.

As for mirror styles, we recommend the traditional mirror type used on this Mark-15 instrument (as opposed to so-called "full view" models discussed under sextant mirror types in the FAQs on our celestial nav home study course.

Arc -5° + 120°, radius 178 mm
Micrometer 1' scale, vernier 0.2'
Mirrors 50x40 mm index, 40x30 mm horizon
Shades 4 index, 3 horizon
Weight = 1 lb.

Compare Plastic Sextants.


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