Celestial 229 vs 'Calculator Method' ?

[Benz]

For me part of the fun of celestial nav is doing it without electronic aid. If I'm turning on a machine, it may as well be the GPS. When I've been keeping in practice, I can do a reduction (altitude measurement to plotted LOP) in five minutes using HO 229. Sometimes it takes my GPS longer to find itself! Sadly, I still rely on a battery watch, but hoping to pick up a windup chronometer one day. The calculators are neat toys, but entirely unnecessary if you can do basic sums.

[P_Dub]

Originally Posted by TheWatchman

I also would like some input on PC programs for CN.

Anybody using their laptop to calculate position?

There exist many PC Programs for doing it and great circle as well.
In particular SkyMate Pro is quite good an easy to use.
Regards.

[artjohnston]

Originally Posted by sneuman

With a good scientific calculator, it seems to me dispensing with the tables is preferable - but I am in the middle of my (self-taught) education on the subject.

Is there any reason I would want to instead use the pub 229 tables (or 249, for that matter)?

Every boat should have a calculator or two on board, and the calculator method is great to teach about the underlying trig formulas for sight reduction. But calculators have disadvantages:
1) They are very error prone (compared to 229 or249) due to the many key punches needed to reduce a sight. You have to do all calculations twice (or more if you find a mistake) to have any certainty in your results.
2) Compared to HO229 or 249, the calculator is slower (even with multiple memories), even if you don't have to repeat your calculations. Time the two methods and you;ll find 229 is clearly faster.
3) I teach cel nav and many people are interested in cel nav, but it is not easy to understand. Trying to get that cel nav understanding, then teaching the basics of sines, cosines, inverse sines, sexigesimal conversion, how to use all that on a calculator, store and recalling memories, etc. can be just too much for some people. If you are a math and calculator nerd, by all means use the calculator method, but many people don't have that skill set to start with.
4) If you are really needing to use cel nav (compared to just playing around and seeing how close you can get to the GPS lat/long), an assumed position (needed for 229 or 249) is not a big deal because you really don't know exactly where you are anyway. You still have to plot the LOPs.

Of course if you are interested in speed, just get a program like CelestNav for a PalmPilot or StarPilot for the TI86. I recommend CelestNav as being very quick and compact and inexpensive. Or get the dedicated calculators that are mentioned. All you need then is a time piece and a sextant.
But you still need the knowledge that you can only get by having a nautical almanac, a calculator, or 229, and knowing what you are doing.

[santa clara]

As a matter of interest which is the most compact publication 229/249/214?

Cheers Martin

[hellosailor]

"But calculators have disadvantages:
1) They are very error prone "

I would suggest an inexpensive Palm IIIxe or similar "obsolete" Palm PDA, which should run $10-25. They're damn reliable little units. And then another $15 (?) buys you John Manson's navigation/sight reduction software suite for it. Total price maybe $40 and you have a "dedicated" nav calculator which runs on AAA cells instead of coin cells. Another 10-20 bucks and you've got a solar charger and spare set of those, too.

There are very few keystrokes to make errors with. Granted, any calculator is a weakness (drop it, soak it, run out of power, yes, to be sure) but then again, if you've got almanacs they can be bulkier, pages can get damaged or torn out, and they're also fun to peel pages aprt if they get soaked. Different weaknesses--but similar ones--compounded by the need to have a clear head and not be seasick while you're doing all the looking up. I suppose the "prudent navigator" would carry and use both, just in case. If nothing else, having the PDA gives you a check against your table calculations. And as our IRS can tell you, folks make simple but fatal calculating mistakes all the time, under the best of circumstances.<G>

[P_Dub]

Originally Posted by artjohnston

Every boat should have a calculator or two on board, and the calculator method is great to teach about the underlying trig formulas for sight reduction. But calculators have disadvantages:
1) They are very error prone (compared to 229 or249) due to the many key punches needed to reduce a sight. You have to do all calculations twice (or more if you find a mistake) to have any certainty in your results.
2) Compared to HO229 or 249, the calculator is slower (even with multiple memories), even if you don't have to repeat your calculations. Time the two methods and you;ll find 229 is clearly faster.
3) I teach cel nav and many people are interested in cel nav, but it is not easy to understand. Trying to get that cel nav understanding, then teaching the basics of sines, cosines, inverse sines, sexigesimal conversion, how to use all that on a calculator, store and recalling memories, etc. can be just too much for some people. If you are a math and calculator nerd, by all means use the calculator method, but many people don't have that skill set to start with.
4) If you are really needing to use cel nav (compared to just playing around and seeing how close you can get to the GPS lat/long), an assumed position (needed for 229 or 249) is not a big deal because you really don't know exactly where you are anyway. You still have to plot the LOPs.

Of course if you are interested in speed, just get a program like CelestNav for a PalmPilot or StarPilot for the TI86. I recommend CelestNav as being very quick and compact and inexpensive. Or get the dedicated calculators that are mentioned. All you need then is a time piece and a sextant.
But you still need the knowledge that you can only get by having a nautical almanac, a calculator, or 229, and knowing what you are doing.

Well, the fellow who did ask for a program for sight reduction and great circle (including:- composite Circle) was surely not asking to carry a bundle of tables, he meant a computer program, easy to use, specialy today on 10 inch scale computer. there are many I just name him one that provide all till the year 2100.
Regards and good luck.
P_Dub

[Adelie]

Originally Posted by santa clara

As a matter of interest which is the most compact publication 229/249/214?

Cheers Martin

249 is 3 volumes of which you need 1 or 2 volumes depending on the latitudes you are sailing in. Generally spiral bound so they lay flatter in use.

229 is 6 volumes of which you probably need 2 to 5 volumes depending on the latitudes you are sailing in. Normal binding.

Don't know about 214.

The accuracy of 249 is comensurate with what can be shot from the deck of a small vessel (ie not a ship or superyacht)

[S/V Alchemy]

Year 2100? Someone's making wheat grass smoothies with the 12VDC blender! Hell, I'm younger than most cruisers (relatively), but if I'm still sailing in 2050, it'll be because I'm doing 720s in the Fountain of Youth...

[Adelie]

Originally Posted by S/V Alchemy

Year 2100? Someone's making wheat grass smoothies with the 12VDC blender! Hell, I'm younger than most cruisers (relatively), but if I'm still sailing in 2050, it'll be because I'm doing 720s in the Fountain of Youth...

Longer shelf-life for the product makes it more salable in the first place because the purchaser knows they can resell it later.

[P_Dub]

Originally Posted by Adelie

249 is 3 volumes of which you need 1 or 2 volumes depending on the latitudes you are sailing in. Generally spiral bound so they lay flatter in use.

229 is 6 volumes of which you probably need 2 to 5 volumes depending on the latitudes you are sailing in. Normal binding.

Don't know about 214.

The accuracy of 249 is comensurate with what can be shot from the deck of a small vessel (ie not a ship or superyacht)

Adelie, you can't carry around them books, they are 1.5 inch thick and 10 by 14 inches. As far as 214 tables there is one for each 10 degrees of latitude and permit all interpolations. For your information, I was using them 40 years ago, they are relatively easy to use, but bulky to carry. A good 10 inches computer with a spare battery is certaily preferable. A good computer program for that is SKY MATE.
Regards
P_Dub

[Adelie]

Originally Posted by santa clara

As a matter of interest which is the most compact publication 229/249/214?

Cheers Martin

249 is 3 volumes of which you need 1 or 2 volumes depending on the latitudes you are sailing in. Generally spiral bound so they lay flatter in use.

229 is 6 volumes of which you probably need 2 to 5 volumes depending on the latitudes you are sailing in. Normal binding.

Don't know about 214.

The accuracy of 249 is comensurate with what can be shot from the deck of a small vessel (ie not a ship or superyacht)

Originally Posted by P_Dub

Adelie, you can't carry around them books, they are 1.5 inch thick and 10 by 14 inches. As far as 214 tables there is one for each 10 degrees of latitude and permit all interpolations. For your information, I was using them 40 years ago, they are relatively easy to use, but bulky to carry. A good 10 inches computer with a spare battery is certaily preferable. A good computer program for that is SKY MATE.
Regards
P_Dub

I could see having a problem carry them if they were each 15" thick, but fortunately they are only 1.5", so about 4lb each.

Santa Clara, P-Dub says 214 is 10 volumes of which you need probably half depending on where you intend to sail and assuming they are divided up by latitude like 229 and 249.

If you want to go the book route then 249 seems like the way to go from a size/weight point of view. Cost too if you are buying new. I don't think anyone is printing 214 anymore so you might be able to get that cheaper used.

[hellosailor]

PD-
A computer has other uses but a 10" netbook or pad is still overkill for this job. A Palm fits in the shirt pocket, even in a waterproof case. Costs way less to. Keep the big computer stowed below for other tasks. or sail faster and lighter without it.<G>

Celestial nav doesn't require a high end graphics system, a fast cpu, or a lot of horsepower. Put in the last number, hit enter, the oldest Palm and the newest computer will both give you a result in the same apparent time. "Instantly".

[artjohnston]

Originally Posted by santa clara

As a matter of interest which is the most compact publication 229/249/214?

Cheers Martin

As always, there are pros and cons of everything.

HO 229 comes in 6 volumes, each volume is12"x9"x1" and are hardback and each volume corresponds to a 15 deg band of latitude. But you only need the volume for the latitude you are using it in. E.g. Volume 3 is for latitudes 30-45deg (N or S). So you might only need one volume. And for practice you only need one volume. You can use HO229 for any celestial body. You can also use it to compute distances, great circle sailing, etc., anything you could use spherical trig for. There is not a time limit to its usefulness. You need only buy the Volume you need.

HO 249 has three volumes (same size as HO229), but are arranged totally different. Vol. 1 is ONLY for a very few selected stars (arranged for optimal sighting for your latitude and LHA), is VERY fast for those few select stars, but can't be used for the sun, planets, moon, or other stars. It also gets out of date every ten years.
HO 249 Vol. 2 & 3 are more like HO229 in that they solve the spherical triangle. Vol. 2 is for latitude 0-40deg (N or S) and Vol. 3 is for 39-89deg (N or S). BUT these two volumes can only be used for bodies with declinations between N29 and S29deg. So it works for the sun, moon, planets, but only some stars. Due to those limitations, it can't normally be used to solve general spherical triangle problems (like great circle distances or sailings, but those are very easy to do with a scientific calculator).

So I would recommend buying the one appropriate HO229 Volume for your latitude (Vol. 3 is readily available on used books websites).

Both HO229 and 249 are getting harder to buy. The "commercial" editions are running about $20 from places like Celestaire.com The "commercial" editions are smaller than the real editions and are softback, but they don't lay flat on a nav table, harder to read, poor quality paper, and kind of suck compared to the real editions. The "real" editions are published by the US Govt. Printing Office, but I'm having a hard time finding them these days.
You can readily buy the real editions on used book sellers or eBay for around $10-$20.

I'm too young to have experience with HO214 and haven't been able to find them for sale even on used book websites..

[sjcdwright]

Always have 2 methods and this applies to calculators as well ? I have used a HP42s for years (Batteries last 2 -3 years) and recently acquired a Toshiba Thrive tablet, which is neat also for Web surfing using wireless at Marinas. This has a free HP42s emulation APP (Android), so now my program works on the tablet as well. Makes planning those 3 shot star sights in the morn/evening a snap, and I have a backup (apart from Tables !)
This would work on a laptop/PC as well as there is an HP42s emulator for that as well (free42forwindows).

[David M]

Some if it might come down to whether or not you see yourself as a purist and want to be able to do it without any electronics.

Seems silly to learn something that is old fashioned like celestial and then not be able to do it the old fashioned way, by sight reduction tables.