How to do celestial today

[sailsw00]

Oh wise ones:
I used to be pretty good at celestial, having used it and taught it in various locations around the world, but I haven't picked up a sextant since GPS became so available, or since my Tamaya NC-77 became extinct. I want to get current again, but how? Is the Nautical Almanac still published in book form, or just as a download? Is there a generally-accepted program, calulator, or software that most folks use? Any suggestions on this "reinventing-the-wheel" application of technology would be apperciated.
Thanks.
-Steve, currently sailing out of Porto Belo, Santa Catarina, Brazil

[Steadman Uhlich]

Howdy!

I like your topic. I hope someone gives you a good, serious answer too.

What follows is written in a friendly tone and added in a gesture of a little humor.

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Here is the modern method for using a sextant:

1. Take a sextant. Take sights. Plot a fix.
2. Take a GPS. Note the GPS position on the same chart.
3. Compare the two positions, after reading about the accuracy of that GPS.
4. Put the sextant back in its case, or mount it on a bulkhead as a decorative item or conversation piece.
5. Use the GPS.

[jstevens]

Steve,
Nothing has changed with celestial since your were "good" at it. The NA and reduction tables are still available in book form. What do you expect has changed?
If you want to use a computer to perform the reduction and plotting, OpenCPN has a celestial plugin that probably does those functions (I've not used it). However, that sort of defeats the old school value of celestial - that said by a guy who wrote his own celestial navigation software.
In any case the only way (IMO) to resurrect the skill is to start taking sights.

John

[farshore]

It's done the same way! Don't let the digital technocrats discourage you. Break out your sextant, chart, plotting sheets, chronometer etc. and take some sun sights. The nautical almanac is widely available as is 249 or 214.
Google " celestial navigation work sheets" and print some out. You don't need the NC 77 to add and subtract.(they were a good time saver). The DOD can and has selectively shut off GPS in trouble areas. There's few if any i-pad sailors that know the leeway of their own vessels on various points of sail, can estimate speed, plot current vectors , construct charts or understand Great circle sailing,even correct and steer by compass! Hell I have sailed with many who can't trim sails without wind instruments telling them how hard and from what direction the wind is blowing. (And that's not at night...) Get back in the saddle! You don't want to become a digital Borg....
PS. Spent a lot of time down that way,
Pomerode and Florrinopolis...beautiful!

[Dsanduril]

I still do it the same old way we learned back when it was the only method available. Same Mk I eyeball, same Mk I pencil, and same almanac and site reduction tables. I find it to be a pleasant way to kill and hour each day while on passage, and to connect with the universe around me.

I'm sure there's an app for that, but I really can't be bothered to fire up the computing device just to reduce a site. The one new thing? I use the GPS for its clock Do have a decent timepiece on the boat and check its accuracy before each passage, but when taking sites I just have the GPS clock display up in the cockpit and use that. I, at least, find that somewhat humorous.

[Stu Jackson]

Let's try it again:

Yes, they are still published. In many boating forums I have suggested the use of Google or any other internet search engine for finding answers to some questions that may not be boat-specific. Sometimes I have been flamed, but I have found that in many cases, the answer to a "Is something available...? or "What is the best price for...? can be found with a simple search.

*************

Good for you for wanting to get back to it. It has nothing to do with borgs, although I must admit I haven't run into one that was particularly friendly recently.

As for folks who need instruments to find out where the wind is coming from, that's a new one on me. Probably happens more often than I can wrap my head around though.

[bletso]

Yes the nautical almanac is still published yearly. Just go to Amazon, that is where I got my copy.

[Bulawayo]

I'm surprised that no one else seems to use air tables? Am I alone in doing so?

[Sdwcheney]

Take a stopwatch, get the exact time of sunrise, or sunset, you do not even need a sextant. This works well enough for a sailboat moving less than 7 knots.

[tstano]

I used Starpath Celestial Navigation home study, they had all the materials.


All U Get

[hodgmo]

I created a brief primer detailing the steps in a sun sight reduction (using the NA) to help a friend who also wanted to get back into celestial. It's ~8 MB pdf - PM me if you'd like me to email it to you (I don't see how to post a pdf in the forum).

[Dsanduril]

Originally Posted by Bulawayo

I'm surprised that no one else seems to use air tables? Am I alone in doing so?

You're not alone, for the most part I use HO 249 (sight reduction tables for air navigation). As someone else posted above on another point, close enough for a heaving sailboat moving at 7 knots. Sometimes use HO 229 just to try to keep the memory fresh.

[PangurBan]

Originally Posted by Bulawayo

I'm surprised that no one else seems to use air tables? Am I alone in doing so?

Good point, Bulawayo. The air tables come in three volumes against six (is it?) for the nautical. Also they are more user friendly. Only disadvantage is you have to replace Vol. I (star sights) every 5 years. What I like to do is solve the nav triangles directly with the equations. This has the advantage of allowing you use your DR position instead of an assumed position. You can download the entire Air and Nautical SRTs free from the U.S. Coast Guard site.
To tell the truth I only use cel nav for recreation and to keep in practice. When the chips are down its GPS for sure.


Sent from my iPad using Cruisers Sailing Forum

[Chuck Hawley]

I think there are always two parts to celestial: finding the GP of the heavenly body (isn't it odd how we still use this term, and I am an atheist...) and solving the navigational triangle. Those two functions are why you need two books or tables.

I'd really like a relatively simple iPhone app that would allow this. But those that I have looked for are really expensive and probably do too much.

But it would also be nice to have the app select the best stars for morning and evening sights. And perhaps substitute planets for stars if one happened to provide a good three "star" fix. And possibly compute my position based on two LOPs.

I guess that's why the iPhone app costs $80 or so!

Incidentally, I totally agree about Blackcrow. If you can't say something nice, go to some hate-filled forum and discuss your opinions there, please.

Chuck

[Bulawayo]

Originally Posted by PangurBan

Good point, Bulawayo. The air tables come in three volumes against six (is it?) for the nautical. Also they are more user friendly. Only disadvantage is you have to replace Vol. I (star sights) every 5 years. What I like to do is solve the nav triangles directly with the equations. This has the advantage of allowing you use your DR position instead of an assumed position. You can download the entire Air and Nautical SRTs free from the U.S. Coast Guard site.
To tell the truth I only use cel nav for recreation and to keep in practice. When the chips are down its GPS for sure.


Sent from my iPad using Cruisers Sailing Forum

Yup....snap!