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post #11 of 72 Old 04-04-2007
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I hope that all this discussion about sextants and GPS blackouts does not make us forget the essentials, i.e. coastal is very different from offshore navigation and any aid in position finding still needs common sense and is not to be used independently and automatically. It is also very encouraging that the broad consensus among contributors to the thread suggests that ANY system is liable to disruption, particularly when you need it most!
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post #12 of 72 Old 04-04-2007
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Tenuki,

I second the motion re: a metal sextant. Don't waste time with the plastic ones, if you're serious about celestial.

Expect to pay 500-700 for a good used Plath or Tamaya. The Chinese-made sextants are excellent, too.

If you act fast, there's one on eBay coming up in 5 hours...new, and current price is $325. eBay: Celestaire Astra III B Marine Sextant (item 180102420824 end time Apr-04-07 20:51:08 PDT)

Good luck,

Bill
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post #13 of 72 Old 04-04-2007
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BTW, you can download Bowditch's for free... it's available in PDF form. I personally like the book, Boater's Bowditch, which was written specifically for the small craft navigator... Much more readable and user-friendly.

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post #14 of 72 Old 04-04-2007
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Also, the Astra IIIB Deluxe is not a bad sextant. I've compared it to the Cassens & Plath I have and got one for everyday use on my boat. Keep the C&P down below in a box as a backup... beat up the Astra...

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You know what the first rule of sailing is? ...Love. You can learn all the math in the 'verse, but you take
a boat to the sea you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps
her going when she oughta fall down, tells you she's hurting 'fore she keens. Makes her a home.

—Cpt. Mal Reynolds, Serenity (edited)

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post #15 of 72 Old 04-04-2007
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Chrondi,

Truer words never spoken. Thus, each of us should carry:

1) A GPS
2) A Sextant
3) A good book on how a sextant works
4) A Bucket with a toilet seat


The Gps will be usefull 99.9999% of the time. When it fails because China shoots down all the satellites with nuclear weapons or the sun blows up, you will need your sextant as a backup. However, since you have completely forgotten which side is up on that bronze medallion, you will need the book of instruction. Since, even with the book, you will STILL have no idea what the hell you are doing, you will need the bucket with toilet seat to spend the coutless hours and days trying to navigate the stars (a sextant does not work well in the head). It is after the third day of realizing that the sextant has narrowed down your position to somewhere between the Atlantic ocean and the Pacific Ocean, the book will be of especially good use since by then you have run out of toilet paper.

Yes, everyone needs a sextant and a book. Or better yet, "if you get lost, just pull over and ask for directions."

- CD

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post #16 of 72 Old 04-04-2007
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"Coronal Mass Ejections"

I am a satellite communications engineer by trade and I have to deal with this phenomonem fairly regularly.

Solar flares or more properly Coronal Mass Ejections occur when disturbances on the surface of the sun "burp" and millions of tons of solar material is flung into space. This material is highly charged and when it reaches earth is pushes the earth's magnetic field away from the sun. When it passes by, the magnetosphere rapidly returns to its original position. Remember science class where a magnetic field was passed by a conductor? Ya got current! Ok now imagine the earth is that conductor and the big magnetic field around it moves. Ya got lotsa current! It is enough to disrupt radio transmissions on earth and from satellites. It also causes power surges in electricity transmission grids.

My GPS tells me when it does not have enough signals to work a course or speed. I love my GPS, but I agree with the thought that it should not be used without an alternate means of navigation.

Gil
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post #17 of 72 Old 04-04-2007
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Yes, like I said two posts earlier, when the sun blows up, that sextant will be very useful. Everyone should own a sextant.

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post #18 of 72 Old 04-04-2007
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Talking No need for a sextant

Nope, when that happens you won't need a sextant. You will need some tissue for your nose to wipe the s--t off. That usually happens when you put your head between your legs and kiss your A-- goodbye!

Gil
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post #19 of 72 Old 04-04-2007
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The truth is that 99% of the people on this forum do not even know what a sextant is. The 1% that are experts, half of them could not narrow down their position with a sextant any more accurately than "somewhere between Africa and Hawaii."

(SMILE)

- CD

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post #20 of 72 Old 04-04-2007
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Quote:
Originally Posted by Cruisingdad
The truth is that 99% of the people on this forum do not even know what a sextant is. The 1% that are experts, half of them could not narrow down their position with a sextant any more accurately than "somewhere between Africa and Hawaii."

(SMILE)

- CD
especially since your list didn't include a clock or almanac/calculator.... ;P

Last edited by tenuki; 04-04-2007 at 06:49 PM.
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