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Old 24-02-2013, 06:58   #16
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Re: Self Taught Celestial

To be serious (and assuming the bad scenario of 'if all electronics fail' above) you need an accurate mechanical timepiece. These are very expensive. Possibly more expensive than a plastic sextant.

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Old 24-02-2013, 11:25   #17
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Re: Self Taught Celestial

iPhone time apps are good when you are in cel range. Use that to rate your regular timepiece. A cheap Casio or timex is okay once you know it's rate. then you simply calculate the correction when you need accurate time. I start counting to thousand-five when I have my observation and look at my watch then and subtract the five seconds. No hack watch needed.

At sea iPhone time server apps are of course useless. But a cheap sw receiver will get you the WWV or WWVH time ticks. Good for checking your watch.

Don't just set your watch to the correct time. Observe and record the difference and divide by the number of days since the last reset. Then you can always calculate the correction even when you have no way to check your watch time.
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Old 24-02-2013, 12:03   #18
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Re: Self Taught Celestial

Hello Monster! Here's a different way to approximately confirm where you are at, while sailing. Pilots who fly IFR (following Instrument Flight Rules), must communicate specific positions, when they are reached, to air traffic control centers. These positions are marked on flight charts as "radial fixes - solid triangles markings on some charts" transmitted from land-based navigational beacons; VOR's (Very High Frequency Omni Range Radio). You can superimpose these positions on a navigational charts using their longitude and latitude. You will not be able to listen to the Morse identifier codes for VOR's or for air traffic controllers, because of line of sight transmission limitations. You should, however, be able to listen to IFR pilots overflying and confirming these mandatory fixes, as they have names; an air band scanner is good enough to hear the one-sided communication, thus re-confirming the proximity of your position. <Much more fun, than using a sextant.> Mauritz
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Old 24-02-2013, 13:38   #19
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Re: Self Taught Celestial

Hi
Just got back from PVR and our new (used) Catalina 30 that we purchsed. he people we bought the boat from was seriously into celestrial naviagation. Found a sextant and many books and manuals on same. I probably will never get into it so I'm willing to part with these. If your interested let me know and I'll try and get you a list of books. although probably outrdated they should be good reference. Too much for my brain I think. I can also take some pics of the books I have and send them along to whoever might be interested.
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Old 24-02-2013, 13:52   #20
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Re: Self Taught Celestial

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Hi
Just got back from PVR and our new (used) Catalina 30 that we purchsed. he people we bought the boat from was seriously into celestrial naviagation. Found a sextant and many books and manuals on same. I probably will never get into it so I'm willing to part with these. If your interested let me know and I'll try and get you a list of books. although probably outrdated they should be good reference. Too much for my brain I think.
The almanac will be out of date and not mucch use but if you have HO229 sight reductiin tables they will be usable. Orcany other sight reduction tables for that matter. What brand on the sextant? It is in a case, right? Maybe post a for sale threadcwith pics. Somebody will want it Im sure.

Do think twice before blowing it off, though. There are simple things you can learn with little effort, like latitude by LAN for instance. You dont have to learn it all at once.
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Old 24-02-2013, 13:59   #21
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Re: Self Taught Celestial

Yes, sextant is in case. It's a plastic one, not sure of make. The tables are older ones. I'll make a list and post in classified. Thanks
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Old 24-02-2013, 14:27   #22
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Re: Self Taught Celestial

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But if you are still determined to buy a sextant, you also need to buy an abacus and a slide rule to complete the set.
I have a Davis Mk 15 sextant and was going to learn celestial. But shoot, if I need to get an abacus and a slide rule too, then forget. Unless someone has any sources for reasonably-priced abacuses and slide rules.
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Old 24-02-2013, 14:48   #23
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Re: Self Taught Celestial

Triton! Please don't buy an abacus or a slide rule! I was just making a point of how archaic the usage of a sextant is. In my opinion, it belongs in a museum. Use a GPS to get your latitude and longitude. Have a couple of them on-hand, just in case one tells you that you are in Zanzibar, while the other tells you that you are in Istanbul! If the third GPS tells you that you are in Tefoa island, it is time to sell the boat or move to another planet! Mauritz
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Old 24-02-2013, 14:57   #24
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Re: Self Taught Celestial

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Originally Posted by barnakiel View Post
To be serious (and assuming the bad scenario of 'if all electronics fail' above) you need an accurate mechanical timepiece. These are very expensive. Possibly more expensive than a plastic sextant.

Chronocentric


b.
no, you do not need to buy expensive. I have casio g-shock gw-6900-1er watch I paid 120, this days you can get it even for 80.

15 seconds per month, 1/2 sec daily, more than enough to be used for good astro navigaton
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Old 24-02-2013, 15:28   #25
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Re: Self Taught Celestial

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Triton! Please don't buy an abacus or a slide rule! I was just making a point of how archaic the usage of a sextant is. In my opinion, it belongs in a museum.
one could say the same about the idea that wind moves boats over the ocean, bicycles, horse riding and restoring vintage cars. You just dont get it do you....!

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Old 24-02-2013, 16:02   #26
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Re: Self Taught Celestial

Don't forget to dial-up using Hayes modem, at 300 baud, to log into here! Mauritz
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Old 24-02-2013, 16:10   #27
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Re: Self Taught Celestial

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Originally Posted by Teknav View Post
Hello Monster! Here's a different way to approximately confirm where you are at, while sailing. Pilots who fly IFR (following Instrument Flight Rules), must communicate specific positions, when they are reached, to air traffic control centers. These positions are marked on flight charts as "radial fixes - solid triangles markings on some charts" transmitted from land-based navigational beacons; VOR's (Very High Frequency Omni Range Radio). You can superimpose these positions on a navigational charts using their longitude and latitude. You will not be able to listen to the Morse identifier codes for VOR's or for air traffic controllers, because of line of sight transmission limitations. You should, however, be able to listen to IFR pilots overflying and confirming these mandatory fixes, as they have names; an air band scanner is good enough to hear the one-sided communication, thus re-confirming the proximity of your position. <Much more fun, than using a sextant.> Mauritz
lol, if you are far enough off shore to want to use a sextant you won't get much useful VHF-AM radio traffic. But if you are going to Hawaii you should just follow the contrails!
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Old 24-02-2013, 16:20   #28
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Re: Self Taught Celestial

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Originally Posted by Teknav View Post
Triton! Please don't buy an abacus or a slide rule! I was just making a point of how archaic the usage of a sextant is. In my opinion, it belongs in a museum. Use a GPS to get your latitude and longitude. Have a couple of them on-hand, just in case one tells you that you are in Zanzibar, while the other tells you that you are in Istanbul! If the third GPS tells you that you are in Tefoa island, it is time to sell the boat or move to another planet! Mauritz
Don't you have a door mount for a sextant like we had in the single Otter? Speaking of slide rules, hope you didn't forget how it works:
http://www.stefanv.com/aviation/flight_computers.html
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Old 24-02-2013, 16:27   #29
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Re: Self Taught Celestial

ahaha, I would understand those against astro navigation if they have state of the aart electronics, but 99.9% have cheap laptops and pirated cm93 or navionics last time updated 5 or 10 years ago, or iphones & blackberries that they got it for cheap (pay monthly). if they have to "buy" mobiles phones, 300 or more (pay as you go) probably most of them would see GPS chart plotter only in the picture or in the shop window.
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Old 24-02-2013, 17:39   #30
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Re: Self Taught Celestial

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Triton! Please don't buy an abacus or a slide rule! I was just making a point of how archaic the usage of a sextant is. In my opinion, it belongs in a museum.
I wasn't serious. I will have two handheld GPS units when I go offshore. But I will also have a sextant and the necessary publications to determine my position using celestial.
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