Sextant

[jerryrlitton]

Guys/gals I have a question here. I am in Seoul, Korea. I visited an antique store and I spied some interesting items. Mostly I was looking at a few sextants. Now to begin with I have no knowledge on the use of a sextant however one day I hope to learn the use. But for the time being I do have an appreciation for fine gear and I saw 2 different pieces. One is a Path from Germany. I looks complete in the (looks like) the original wooden box except for one small piece. The box has two small slots in the forward side. One is filled with an Item that looks to be a lens cover. The other slot is empty. All the pieces on the sextant itself appears to be complete. (mirror and lens filters. It is tight with no play in the mechanism. The other is a Ross (London) same condition. They want 225 USD for the Path and 185 for the Ross. What shall I be looking for and what do you think of the asking price. It is 2200 here on the 6th and I will be here for another 3 days. Thanks in advance.

Jerry

[sailingdog]

Do you have anymore information, like model, etc??? Are these micrometer drum style sextants or vernier scale units?

Also, highly recommend you check the sextant for parallax error and arc error. This can be done relatively simply, without much in the way of tools needed. I have the procedure for this written down at the house, and will post an abridged version of it when I get to the house tonight, if I can find it.

[killarney_sailor]

I assume it is a Plath rather than a Path. If it is the latter I have never heard of it, but Plath is an excellent make. The Ross might be either a) an antique or b) a reproduction. There are lots of reproductions around that look lovely but are meant for display rather than use. If it is an original you should be able to tell by its condition - the patina on the metal and also by any documentation that comes with it. An original in excellent condition should work just fine even though it is very old.

Think I would go with the Plath myself since it is likely newer and parts might be easier to find.

[ffiill]

No real need to check the errors as they are easily adjustable-but for index set quadrant to zero degrees-look at a horizontal edge-a hill,a house roof,a flat horizon.If the line of the horizon seems to have a step in it adjust using micrometer drive until step disappears.This read off on the micrometer and quadrant is the index error.
To reduce it to a minimum you have to adjust mirror using the little set screws you will see attached to the mirror frames.
Beware there are some repros around designed to fool because any good sextant is worth several hundred dollars at least-a good quality classic a great deal more.
Some of the best but rare are those produced by Hitlers 3rd Reich for the German navy-a friend of mine had an old u boat one.
If you have time sextants are fun and I guess if you enjoy the maths.You have to work out what a GPS does instantly

[jerryrlitton]

Killarney, it is a Plath. Here is what I remember and I kick myself for not taking pictures of it; The plath when brought into the use-position the dog ears when squeezed together (I know some of you are positively cringing on my lack of proper terminology here) enabled the movement of the eyepiece along the arc. However I think it was a drum type and when turned for the fine-tuning it would only rotate about 360 degrees. That movement was not along the arc but for and aft and would move along the tangent. The Ross dog-ears for 90 different from the Plath and it had vernier style adjustments and would rotate more then 360 degrees without the mechanical stoppage. Both look very old. I doubt either one would have a certificate of accuracy. I need to check again.
Now how can I tell if these are reproductions and if they are not how can I get them calibrated to usable standards?

Thank again guys,

Jerry

[hellosailor]

FORGET THE ROSS THEY ARE FOR THE SUCKER TRADE. Literally, they are meant to be sliced up and used as end table lamps or award placques.

The Plath might be real, might be a Cassens & Plath or a "C. Plath", two different firms. Your best bet is to look at the models online and see what you are looking at. There's only one Plath left in business today, and they are very, very, kind to their customers including folks who are trying to buy and repair used instruments. Odds are that you could call them (they respond to emails in English with no problem) with the serial number and description, or email a photo to them, and they would tell you right away what you are looking at.

If a sextant has broken parts, i.e. a cracked mirror or gear, that can often be replaced. (Robt. White out of Boston are one leading source for that, also outstanding folks.) But if the frame itself has been BENT from being dropped, etc., then it may be junk. So you need to take a good look at it, eyeball it closely, and see if there are any signs of gross abuse.

In terms of adjusting...probably Bruce Bauer's "Sextant Book" (I've probably mangled part of that) is the best guide to that. Celestaire.com should have that available on their website, as well as the current Plath sextants.

A Plath was shipped with a certificate of accuracy, but a careful owner can always re-adjust it to original accuracy--if it hasn't been bent. The accuracy from the factory is usually way beyond what even the most proficient small craft navigator can use, so having the actual certificate and knowing the actual limits is of limited value.

When I acquired my Plath I emailed the factory to ask about a manual, spare bulbs, and whether a new part could be obtained (one of the plastic parts had cracked, unseen until I stripped it down). I didn't hear from them, so I made up a new part from some brass stock. A week later...there was an air mail packet in my mail box. Two new bulbs, new manual, new plastic bit, letter thanking me for becoming an owner, AND a little brass plaque with my name engraved on it.

Customer service doesn't get any better than that!

Any full-sized Plath, even needing some TLC, for $225 US would be a steal. the top models sell for about $550-600 on eBay when and if they come around, there's not much traffic in the sextant market these days.

[Flybyknight]

Close your eyes and grab the Plath.

Dick

[ffiill]

Check out the following from Davis Sextants-everything you need to know about setting up and using a sextant.
Checking the index error is a good idea because if its a long way out from zero-say even 5 degrees sextant might be bent!
http://www.davisnet.com/product_docu...0_IM_00025.pdf

[jerryrlitton]

Thanks to everybody here I was involved with a straight up learning curve. Hellosailor your help was great. I almost bought one of the sextants until I spied the serial number..."8054" which seemed very low. I figured I had an old sextant until I saw another one with the same number. Anyway I think I am going to have to order a new one from Plath, you get hat you pay for right? I am back in the US now and we had a great trip.


Jerry

[Boasun]

I have a C-Plath #10182
The box for the sextant has the certificate on the underside of the lid and it has the same number.
Check the box it is coming in for that certificate because it has data that could affect your star/sun sights.
And mine was made in West Germany....
Yes it is that old and with care it could be passed on to my great grand children. That is if my son ever makes up his mind and settle down and produce a grand child or two for me.