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» Online Classroom   »   » Public Discussion of Cel Nav   » Which Almanac/Sight Reduction Table should I buy?

   
Author Topic: Which Almanac/Sight Reduction Table should I buy?
BOF


 - posted January 14, 2009 07:02 AM      Profile for BOF           Edit/Delete Post 
(Posted at the request of David)

I am just getting started in the art of celestial navigation, and am seeking advice on which pubs to buy for use.

Can I get by with just the Nautical Almanac, or will I also need copies of HO229 or HO249?

If I need copies of HO229/HO249, which volumes should I get?

And what are the advantages and disadvantages of using HO229 as opposed to using HO249 (or vice versa)?

From: Landlocked in Denver
Capt Steve Miller


 - posted January 14, 2009 08:02 AM      Profile for Capt Steve Miller           Edit/Delete Post 
A Nautical Almanac is the first reference to purchase and is vital to Celestial Navigation. It includes the commonly refered to NAO tables that perform Sight Reduction. This means only one book needed.

That being said the 249 Sight Reduction Tables are the most common tables used and are probably the easiest to learn, these were developed for air use. There are 3 volumes to the set. Volume One for selected stars, Volume Two and Three are Latitude based, so your Latitude of operations will dictate which you would purchase.

The 229 Sight Reduction Tables, developed for marine use, consists of nine volumes again based on Latitude in 15° increments. There is an extra step involved in Sight Reduction with 229 as opposed to 249. So, again your Latitude of operations would dictate which one or two volumes you would need.

The 249 tables are restricted to Bodies with Declinations below 29° and have the data rounded to the whole degree. The 229 tables have no restriction on Declination and the data is carried to one decimal place.

I feel that the Sight Reduction Tables used become a personal choice. I personally prefer the 229 tables, but I do focus on 249 on my classes and will teach the 229 if requested.

From: Starpath
David Burch


 - posted January 14, 2009 02:16 PM      Profile for David Burch           Edit/Delete Post 
Please note too that these books and the options, pros, and cons, are discussed in the course materials and in the text and online glossary.
From: Starpath, Seattle, WA
David Burch


 - posted January 14, 2009 04:38 PM      Profile for David Burch           Edit/Delete Post 
On checking your question, it is IMPORTANT TO NOTE that you do not need any of these publications to work the course. all table selections are provided. Also to get a feel for the tables, we have links to all of them online at www.starpath.com/navpubs

thus it is likely best to wait till you have used some of the samples before purchasing.

From: Starpath, Seattle, WA
BOF


 - posted January 16, 2009 02:39 PM      Profile for BOF           Edit/Delete Post 
Thanx for the advice.

I already bought a nautical Almanac, but will wait until I finish the course to get a feel for which Sight Reduction Table series I want to use.

From: Landlocked in Denver
vandy


 - posted August 24, 2014 04:47 PM      Profile for vandy           Edit/Delete Post 
Capt Miller,

Your discription of difference in pubs 229 & 249 was very helpful.

Are there any restrictions with the NOA tables similar to that which you listed for pub 249?
Do you still personally prefer pub 229?
Does your class still focus on pub 249?

From: United States
Capt Steve Miller


 - posted August 24, 2014 06:03 PM      Profile for Capt Steve Miller           Edit/Delete Post 
First, a discussion comparing the NAO and 249 Tables are in the student Discussions here on the Forum - search for 249.
Second, yes I still prefer 229 when I do sight reductions.
Third, yes most of my students still use 249 for sight reduction.

From: Starpath
David


 - posted January 22, 2016 12:25 PM      Profile for David           Edit/Delete Post 
It is possible to download these for free on the internet
From: Minnesota
David Burch


 - posted January 22, 2016 01:19 PM      Profile for David Burch           Edit/Delete Post 
these tables or links to them should be provided in the course materials. see also www.starpath.com/celnavbook
From: Starpath, Seattle, WA


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