I have a CPlath Trommel Sextant (see attached) that I would like to trade for a Freiberger Yacht Sextant. I use sextants on a daily basis while sailing long distances teaching new (and a lot of not so new) sailors about offshore sailing including a serious working introduction into celestial. The CPlath (my second one) is too fine of an instrument to let the students swing around. Also, for a new shooter the CPlath is much harder to use than the Freiberger I have.

I am located in Germany, when I am not sailing in the Atlantic or Med, so let's consider shipping.\

Bob

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I was wondering if the Mark 25 "beam converging" mirror can be retrofitted to the Mark 15.
 Davis says the split mirror of the Mark 15 can be fitted to the 25. The dimensions for the replacement parts are similar but not exactly the same. Maybe the reverse is not true. Would anyone happen to know?

I may end up getting a mark 25 anyhow if one pops up on ebay in my price range, in the meantime changing out the mirror might be an economical option.

I think the instructions for Sight Reductions needs to have something like the following:

*  Assumed Position for east longitude use DR longitude integral degree plus 60'-GHA minutes for the minutes, If you are at 35° east and the GHA minutes are 33' then AP is E35° 27'  (60'-33'=27') 
The instructions work for West.

What do sextant filters filter?

I think this is an important question when looking at the sun. If only visible light is filtered, my pupil widens and lets all ultraviolet through, like with low quality sunglasses. This will harm my eye.

Mine is a second-hand Freiberger sextant - I cannot find any specifications. Does anybody have any information?

Regards

I've just written up a procedure for finding which stars will be on your meridian, generally, on the first day of each month of the year at 7PM Local Standard Time.

It uses the USNO's Navigational Star Chart which, if you study it for a while, is full of helpful information.

You can get it here- Navigational Star Chart- how to use it for star identification

'Hope it's beneficial to you.

Following seas,

Johannes H.

Merry Xmas and Happy New Year to all of us. Looks like we're still holding the fort.  Good job we're doing.

Toast:

To all of us, members of Celestial Navigation Forum.  May we keep sanity in the world which can't live without extra battery. Let's drink!

Does anyone know or have a link that explains what exactly the values for A,B, F, P etc represent in a sight reduction?

 I was asked recently and I know anything with H has to do with altitudes and the Zs are azimuths but the rest I don't know with enough certainty to pass on.

Thanks

Do you have a preference for time display? 

Which do you like better?  Analog or digital?

Do any of you use mechanical watches (not quartz)?  Now wouldn't it just be nice to have a Rolex GMT Master?!

In desperation I've searched the web to hear the sound of a Rolex or Piaget ticking but haven't found anything!

Louis

At Rumata's suggestion I purchased and received, today, a copy of John Caldwell's book, "Desperate Voyage".  The book came autographed by John Caldwell himself!  All for $3.85 from ebay!  In brief the book covers his 1946 solo sail from Panama to Australia.  He got wrecked on islands East of Fiji and is carried by ship to Australia.

The story he tells of his trip is nothing but disaster after disaster.  He didn't even know how to sail when leaving Panama and what happens to him along the way is evidence of that.  It would be difficult for me to describe the troubles he got himself into or that they even happened. 

He taught himself navigation while underway.  Here are a few words from the chapter entitled "Malpelo Isle". 

If you will navigate, take what is listed here and sail away.  When, after ten days of study and stars, you can't fix your position, turn back and take up harbor sailing, for you will never navigate.  Any sensible person who can see the sun or horizon plainly can use these tools to go around the world".

Mr. Caldwell's total navigational instrument cost was $8.90.  The sextant was given to him by a sea captain.

In keeping with my interest in boat names and how well things go for the captains of oddly named boats Caldwell's story is no different.  I'm not superstitious except about boat names.  Don't name your boat anything that challenges or affronts The Great Commodore of the Universe.  Here are some famous boat names and what happened to them;

Titanic.  Titanic is ancient Chaldean for....satanic.
Endurance.  (Shackleton's ship).  Crushed by ice and sunk.
HMS Terror (Franklin's ship) Sunk in the Arctic.  Crew- all died through starvation on land.

So what has that to do with the book Desperate Voyage?  It's this- Caldwell's boat is named- Pagan.  His boat was wrecked and smashed to pieces on an island near Fiji. 

But he alone has survived to tell thee.

It's a very interesting and exciting book so far.

Fair winds....

CelNav57

I was just watching a video about the Volvo ocean race 2014-15 and at this link;

https://youtu.be/vpM12gPOte8?t=34m32s

...it shows a sailor using a sextant.  I do not know what year they show in that excerpt of the video, as the sound is off (intentionally).  Nice to look at.

Paul