Celestial Navigation

[Talbot]

Light is only any use if you plan to do star sights as well! Then they are very useful indeed as they provide enough light to read the vernier without totally destroying your night vision (still a good idea to close your star taking eye while operating the light).

[GordMay]

Battery corrosion gunk is acidic - so a mild caustic, such as Baking Soda (mixed to a paste /w water) is a good neutralizer.

[hellosailor]

"Battery corrosion gunk is acidic " Acidic? From penlight cells??

I was taught it was alkaline (as in alkaline batteries) and that's a "base", which is why mild acid works so nicely to dissolve it off.

Or are you talking about lead acid wet cells, where the "gunk" is indeed son-of-battery-acid?

Baking soda paste is a good mild abrasive though, which should also wash clear (like vinegar does) without affecting the other parts.

[SkiprJohn]

Hello et al.
Thanks for the information. One of the terminals was so badly corroded that it actually broke off when I removed the batteries. So my problem is a bit more complex than cleaning. However, the cleaning tips will be useful when I start trouble shooting other problems with old electronic gear. The terminal that broke was just a 90degree bent piece of copper so it shouldn't be too hard to fabricate.
I think I will spend the time to replace the one terminal and fix the switch because as "Talbot" says, it will be helpful for my star sights.
I remember that on the bridge of my last Cruiser there were at least 5 people helping for star sights. One taking time, another holding a red lense flashlight, another recording, the person taking the sights, and the Junior Officer of the Deck trying to supervise and learn too. It would be nice for me to do it by myself and the light will help.
Regards, --John--

[hellosailor]

John-
David might be able to sell you replacement parts or, if they're really traditional, they might even just GIVE them to you. Copper battery contacts are usually something like beryllium copper, a springy alloy, not plain copper. Odds are you can find a $2 battery holder someplace, or find a battery-powered something in a dumpster (cordless phone?) and pull a real battery contact out of it if needed.
I don't know if you can solder to it, but there's about a 4" x 1/4" long piece of springy metal in the top of most video cassettes. I pulled one apart to get the tape, makes good woolies.<G>
If you can still find a box of old fashioned copper paper clips--I'd bet they'd work well too. Or one of those brass paper-punch-spread'em things we used to put through holes to hold papers together. No idea what they are called, probably 100 to the box for $2.49 these days.

In the meantime, there are places that sell "finger lights", a plastic ring with a small LED light on it that uses two coin cells. Amber, red, all the usual colors, it just light up whatever is at your fingertips, no hands occupied by holding it.

But try Davis first, sometimes some companies surprise us with old-fashioned customer service!

[SkiprJohn]

Hello,
Thank you. I love to see old fashion ingenuity applied to problems such as mine. Will try all before I spend a whole lot of time/money. Turns out there is another wire connection in there that completely corroded away.
Lesson learned. Don't leave batteries in stuff you won't use for years.
At any rate, my noon sights/meridian passage sights are getting better.

Kind Regards, --John--
P.S. It is an AstraIIIb not Davis. Does Davis sell Astra also?

[Islandmike]

Talbot,

I would love to have a copy of your form.

mkanthony@cox.net

Thanks

[SkiprJohn]

Meridian Passage/Noon Sights

My experience in the last couple of months with relearning celestial has only been with meridian passage/noon sights and I'd like to share that you can get "spot on" with latitude and within 15 miles of longitude using just the meridian passage sight. If that is good enough for you then all you need is one sight on a bright sunny day.
What I needed to do to get here:
>I had to buy a new Nautical Almanac 2006 and a new H.O. 249 Vol. I. (The H.O. 249 Vol. I. is not necessary for meridian passage/noon sights)
>I needed to come up with a form that worked for me and jogged my memory each time I used it. (I'm 60 plus)
>I needed to fine tune the second hand sextant that I recently bought from a fellow who never used it or tuned it. (I learned that after taking a few sights and missing by miles)
>I needed to practice sights and calculations

For more accurate sights, "Talbot's" system for Sun/Run/Sun will give you a better fix with two sights and I'll be practicing that later. "Talbot" provided me with his very extensive home grown collection of celestial navigation forms. They are very very good.
I modified his meridian passage/noon sight form and combined it with other forms that I had. I'm certain now it is nearly unrecognizable to him and I will send that to anyone who is interested. Since it is not in "Talbot's" original format I'm certain he won't mind. Please correct me if I'm wrong "Talbot."

Now my noon sights are as good as they can get and I'll be moving on to latitude by Polaris sights.

Kind Regards, --John--

[Talbot]

Only interested in protecting my own versions, cause I would be more than a tad peeved to come across them in a celestial navigation book earning somebody else money!

[SkiprJohn]

Thanks again for all your help Talbot.
Hypothetically - Do you think someone could write another book on Celestial Navigation? I've read at least 7 and they all have the same information except Bowdicth who says everything and more. I think that the 7 I've read all came from yard/tag sales and I never paid more than $1 dollar for any one of them except for Bowditch of course.
I just started reading another one that I found in a box I didn't remember I had. They all say pretty much the same thing but some say it with a bit more flair. The one I like the most is the one I mentioned in my first post.
Kind Regards, --John--

[Talbot]

There are a couple I know off that are worthy of mention. Both by the same author - Tom Cunliffe (a well respected sailor and journalist in UK) I have his Celestial Navigation: What the Ocean Yachtmaster Needs to Know
and there is also
Ocean Sailing: Celestial Navigation, Weather, Passage Planning

The first includes all the detail on setting up the sextant, and the forms and how to complete them. The second is a rather more broad book on Ocean sailing

[CaptainK]

Talbot.

Have you ever thought of writing a celestrial navigation book? You could make alot of money off from that idea. And may make yourself a "real" celebrity within the crusiers circle.

And who knows. Maybe your version may make more sense, if you really do write a book. Hell. I would personally buy that book, myself.

Also. I would ship my book, for you to sign it. Along with a international money order, for a autograph fee!!

[Talbot]

Apart from my forms, I dont think I could really improve on either of these books by Tom Cunliffe, so dont think I will be rushing to put pen to paper.

Thank you for your kind thoughts.

[CaptainK]

You're quite welcome Talbot.:cubalibre

[Zach]

Suzan Howell's "Practical Celestial Navigation" was found in a small book store on my last excursion to the coast. (Needless to say, it came home with me!)

What do you guys think of this book? So far its a lot to wrap my brain around...