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Old 24-01-2012, 18:38   #31
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Re: Celestial 229 vs 'Calculator Method' ?

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As a matter of interest which is the most compact publication 229/249/214?
If you want compact get a copy of Self-contained Celestial Navigation with H.O. 208 by John S. Letcher, Jr. It not only contains the very compact H.O. 208 tables in one slim volume, but it also contains a very good simple celestial navigation text. It is what I taught myself celectial with, which turned out to be very handy because the first guy I ever sailed with offshore used that system since his training dated from prior to WWII. Another very short table is H.O. 211, which is a bit more awkward to use than H.O. 208 but is small enough to store within many sextant cases.
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Old 24-01-2012, 21:37   #32
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Re: Celestial 229 vs 'Calculator Method' ?

In decreasing order of size:
214 - 9vol
229 - 6vol
249 - 2vol
208 - 86pg
211 - 36pg
Concise Sight Reduction tables - 20-30 pages
S Tables - 9pg
Modified Bygrave - 2pg

The full nautical almanac is 1 vol. and as of the 2005 edition it also contained the Concise Tables.

There are long term almanacs of about 10pg or so that are good for the sun and stars at a slight cost in accuracy but good for several decades at a time.

If you have a timepiece of unknown accuracy you can set it within several seconds if you have the full nautical almanac with the moon.
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Old 09-02-2012, 17:29   #33
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Re: Celestial 229 vs 'Calculator Method' ?

Dave
I can understand the desire to do this without calculator and everyone should be able to do this as a backup. (If they have the appropriate tables for the latitude).
As for the old fashioned way... the HO type table route is not old fashioned at all but decidedly modern in fact , about 1940's I think and is merely a documented set of pre computed (by computer) results.
The "correct" way if old fashioned is the "correct way" is to use Napier's (circa 1600's) log tables and haversine tables (All UK navy officers in WW2 used these for nav ) to do your sight reductions. Now there is a challenge.. to keep all that arithmetic straight when feeling under the weather.
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Old 10-02-2012, 13:39   #34
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Re: Celestial 229 vs 'Calculator Method' ?

i wil do noon sight or planet sight or polaris sight faster then with calculator. it will take me more time to enter all data and then calculate position.
and every one can do that. you need literary five minutes to do, let say, noon sight and longitude. same with polaris.
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Old 10-02-2012, 15:07   #35
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Re: Celestial 229 vs 'Calculator Method' ?

Many folks can barely peck-n-hunt on a calculator or computer, but others can enter data much faster than they can miscalculate the old fashioned way.

Whichever makes you happy.

Of course a fast check of the GPS when you're done should tell you if there's been a miscalculation either way.<G>
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Old 06-11-2012, 05:22   #36
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Re: Celestial 229 vs 'Calculator Method' ?

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Originally Posted by Jim Cate View Post
G'Day all,

Way back when I learned on HO249... no batteries, but I found that when at sea using the tables would induce mal de mer in short order. Something about trying to follow those rows and columns of figures whilst bouncing about (on a 30 ft S&S). So I went to a calculator to do the trig. Worked well for me. Then got a HP41 with a Nav Pak and dispensed with the Almanac... even better! Then found the above mentioned DOS PC Nav and thought I'd died and gone to heaven !! It has the advantage of error analysis and averaging multiple sights and built-in star finder... all fits on a floppy disc, too!

So, these days we carry a sextant, an old Almanac with the corrections tables for updating and the various calculators and software... and the usual lot of GPS's. I hope that in the event of catastrophic GPS failure I could find all the other stuff before we ran into something! I know it's down there somewhere...

Cheers,

Jim and Ann s/v Insatiable II lying Towlers Bay NSW Oz

Hello and G'day to all,
I am just getting into nav with a sextant and the suggested PC-Nav sounds great. I would like to find out if PC-Nav is still around and if it is would be very pleased if someone knows a likely source to get it.

Thanks
Prico

Aussie from Williamstown
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Old 06-11-2012, 05:28   #37
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Re: Celestial 229 vs 'Calculator Method' ?

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Originally Posted by Prico View Post
I am just getting into nav with a sextant and the suggested PC-Nav sounds great. I would like to find out if PC-Nav is still around and if it is would be very pleased if someone knows a likely source to get it.

Thanks
Prico

Dont know about PC Nav, but you can try this site
Celestial Navigation

Download the How to pdf book and the zipped program.
I use this to check workings, and its very very good, and free.

BTW, I still manage to reduce sights using spherical trig, as that was the way I was trained some 30 odd years ago
Good luck
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Old 06-11-2012, 05:34   #38
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Re: Celestial 229 vs 'Calculator Method' ?

I do smile when people use advanced technology to do sight reductions!. Why, whats teh point, unless your using the sextant to just pass the time.

Dave
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Old 06-11-2012, 06:22   #39
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Re: Celestial 229 vs 'Calculator Method' ?

When I read back through the thread, it does mention people suffering even more from sea sickness when trying to pull the numbers from the sight reduction tables, and I guess I can sympathise with that.
You may be surprised (or not) that the UK nautical colleges now only teach sight reduction using a scientific calculator.
When I did my tickets, all sights had to be reduced by the folowing methods
Marc St Hillaire
Long by Chrom
Ex-Meridian

No calculators allowed, but a slide rule could be use for checking workings.
At the time I could reduce a sight in less than 5 minutes using Norries Tables, doubt if I could manage that now, but I can still use the tables.
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Old 06-11-2012, 09:42   #40
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Re: Celestial 229 vs 'Calculator Method' ?

Prico-
See Sources for Sight Reduction Software ?
and a google search on "pc-nav sight reduction software" turns up a lot more.

Dave, sometimes the point is just to get the job done. Some years ago I used my Palm PDA with John Manson's excellent Navigation program. My friend and I both shot sights, I had a solution within 20 second and a couple of miles. My friend ground through all the numbers, and after ten minutes came up with one 900 miles off. Then the question was, of course, go back and check the figures.

The donkey (computer) elminates a lot of potential human error. Whether it is a dedicated nav device, or a computer program, or a small well-behaved computer like the Palm. (Still available used for $25, software still available, runs an awful long time on two AAA cells easily obtained or recharged.) If nothing else--it SHOULD be used to check your math. If the results disagree, you know something is suspect.

Nigel, a slide rule IS a calculator. In fact, I sent in my smallest cheapest slide rule, a 6" plastic one, to qualify for a rebate "when you send in your old computer" a long time ago. "Enclosed is my analog computer" and they didn't argue about it. The bamboo log-log-duplex still travels in my nav bag, that's my "solar powered calculator". As long as the sun shines, it can work. <G>
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Old 06-11-2012, 13:22   #41
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Re: Celestial 229 vs 'Calculator Method' ?

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Originally Posted by hellosailor View Post

Nigel, a slide rule IS a calculator. In fact, I sent in my smallest cheapest slide rule, a 6" plastic one, to qualify for a rebate "when you send in your old computer" a long time ago. "Enclosed is my analog computer" and they didn't argue about it. The bamboo log-log-duplex still travels in my nav bag, that's my "solar powered calculator". As long as the sun shines, it can work. <G>

Guess your right, I never got the hang of a slide rule, and for our tickets back then, had to show all the log table workings. My Dad left me one of these
http://sliderulemuseum.com/PocketWat...astleberry.jpg
Occasionally comes out of the box and I try to figure how to use it


Agree on a calculator or PC program to help with sight reduction, but I still enjoy the old method, does help pass a few minutes as well
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Old 06-11-2012, 13:35   #42
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Re: Celestial 229 vs 'Calculator Method' ?

I'm not sure what that is, I don't recognize it as a circular slide rule, which can be very handy but these days, they are pricey antiques.

I suppose getting the hand of a slide rule isn't that hard IF you have a good teacher. I never grasped arctans and radians and circular trig in high school, but when I was learning celestial and someone showed me "this is for straight lines, this is how it works on spheres" the light bulb turned on real fast.

Same thing with a slide rule, and if someone shows you how the "inverse" scales work on it, then a BIG light bulb turns on because you can do multiple operations and never have to interpolate a number until the last one is done. Of course, screwing up the decimal places is still a job left to the user.<G>
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Old 07-11-2012, 02:55   #43
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Re: Celestial 229 vs 'Calculator Method' ?

Better image here
Fowler's Universal Calculator - Gilai Collectibles

Worth keeping hold of, I never checked the value of it before.
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Old 08-11-2012, 14:07   #44
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Re: Celestial 229 vs 'Calculator Method' ?

Each Nautucal Almanac Commercial Edition (paradise cay) has a set of tables for sight reduction using the NASR method. Or you can use the Law of Cosines method with your calculator if it still has batteries. This is rather than carrying a number of large volumes.

For learning you could give your local Power Squadron a try for those in the US.

Regards
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