Are antique sextants any good?

[qwert]

When I was a kid we found an old sextant in the attic (lived in an old english seaport at the time).
It was beautifully made of jet black ebony with the scale and makers name and date etc in ivory, made in London at the same time as the french revolution (1789).

Turned out it was actually an octant. I took some sights down on the beach and the local maths teacher did the calculations. we got to within ten miles.
Often wish I knew what happened to it

[billgewater]

I have an old sextant with a vernier scale. The scale was "re-engraved" in England in 1908. The sextant is still accurate and occasionally used, but it does have a problem and that is with the lens systems. Apparently it uses what are called achromatic doublets which reduce spectrum dispersion (two lens glued together) (a-chromatic mean "without colour"). The glue used in the doublets can and has gone "hazy". The same model sextant can be seen in a maritime museum at Geraldton, Western Australia. In low light levels and with my aging eyesight this can be a bit annoying. Modern sextants usually have better optics. However, like most sailors, I rely on GPS systems as they operate in most weather conditions plus position data is continuous and able to be plugged into autopilots, screens, AIS etc.

[hpeer]

I have a “lifeboat” sextant. Adequate?

[Lepke]

Many of the antique sextants are 1/2 size and come from the days when all deck officers were required to have their own sextant as a piece of professional equipment. After 1900 most ships supplied necessary nav equipment. Some still carried their own better sextant. Life vests, too. About that time, before current CG regulations, many ship owners supplied cheaper tule filled life vests. Professional mariners carried their own. Tule vests, after several years absorbing marine air, usually sank on their own.
The quality of the sextant effects the accuracy of the fix. In the sailing days, being within 1 or 5 miles didn't make much of a difference.

[David M]

At the maritime academy, I was issued a sextant from WW2. It was accurate but the optics were horrible for civil twilight compared to what is available today. The sun sights were pretty accurate.

You could practice with it, but I would not recommend practicing from a moving boat unless you don't mind your LOP's being off by more than 10 miles from a sail boat where the height of eye is low and the boat shakes more.

The guys who could afford modern sextants had LOP's under two miles. Mine averaged out around 4 miles.

Get a plastic sextant. They are inexpensive and the precision is not all that bad. You still have GPS backing you up. If that goes down, you still have DR and a sextant that is still good for maybe 5 miles or so.

[hzcruiser]

Originally Posted by leboyd

The main difference between the older sextants and the new ones is that the new ones automatically adjust for daylight savings time.

Aaaah, that would explain why ships are statistically more likely to run aground in summer!

[Mithril Bham]

Originally Posted by SVTatia

All good replies above.

Another drawback of an antique is that they were usually made of bronze, even if they work they are heavy and hard to use on sailboats.

If a plastic one is going for $300 or so, an Astra is well worth the $650. They are Chinese but the reviews have been very good and they are a robust and well made instrument. They sometimes come up for sale in CF classifieds for a lot less like the one below.

http://www.cruisersforum.com/forums/...-a-224498.html

Second that.
Probably the best for the money.

[leonsk]

about 20 years ago I bought a Russian made navy sextant. Aluminum alloy (same as boat hulls) and very fine condition. Great low price, about the same as one of the plastic ones. Checked it out in the Caribbean but used a computer program for the sight reductions. Checked it with GPS result and quite usable. Only peculiarity is that when sighting you bring the sun UP to the horizon vs. DOWN per usual.

[picklesandjesse]

Originally Posted by leboyd

The main difference between the older sextants and the new ones is that the new ones automatically adjust for daylight savings time.

I bought mine in 1975 and we had daylight savings then. I forgot about that. No wonder I was thousands of miles away from where I thought I was....or was I ???

[Adelie]

Originally Posted by hpeer

I have a “lifeboat” sextant. Adequate?

Yep..

[sailpooka]

You can buy a very nice Celestaire Astra IIIB or Iii Pro for less than $900.
Agreed, anything labeled "antique" related to a sextant is just for the fun of having it.

[charliehows]

Joshua Slocum circumnavigated the world using a cheap tin alarm clock for his chronometer; you could do the same today using a $150 handheld GPS, or a $20 digital watch and a $120 "practice" sextant.

[Epikur]

Real antique sextants are as good as new ones. I bought my russian one for about $ 250,- and couldn‘t resist to buy a Tamaya for $ 160,- (I still need to repair the sight holder though).
Aligning the mirrors is a small thing. Just check google.
It’s difficult to find a reliable time. Don’t trust your „radio controlled“ clock. The App „pilot time“ seems reliable.

NEVER look into the sun without the sun filters.

[Cheechako]

Spam:
Hi, I have an Ebbco (East Berks Boat Company-England) Plastic sextant and Similux 2102-D rotating star finder in nice faux leather case I should move on to someone who will use them. Were used as training aids only. $75 shipped to US lower 48.
http://www.cruisersforum.com/forums/...24#post3011824
listed over in the yard sale...

[sailorladd]

When I was shopping for a sextant I recall a plastic Davis sextant was regarded as the best alternative to one of those solid bronze antiques (which I inherited and used for many thousands of miles) ...but Davis plastic ones are workable and relatively inexpensive...