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» Online Classroom   »   » Public Discussion of Cel Nav   » ASA Celestial test

Author Topic: ASA Celestial test

 - posted September 12, 2007 09:50 AM      Profile for DustyDan           Edit/Delete Post 
I am supposed to do the ASA test soon for the celestial nav before the passagemaking. I ordered a bood from Barns and Noble that had 100 celestial problems and found they used different forms from the avalable tables. These forms are not familiar to me after working your home study course, and I am concerned the ASA test will use techniques that I am unfamiliar with, and forms I've not used in studies up to this point. Should I look for additional material, or am I in good stead with your homestudy program? Thanks DustyDan
From: North Dakota

 - posted September 12, 2007 02:47 PM      Profile for HHEW           Edit/Delete Post 
One of the nice things about celestial is there's only one way to do it. It's like a dance with four places to put your feet. You always make the same four moves and you make them in the same order:

1) You take a real sight.
2) You get a comparison (theoretical, computed, calculated) sight.
3) You compare the two sights to find their difference (intercept)
4) You lay out the difference on a plotting sheet to get a line of position (LOP).

So, if you've learned celestial from one source, you know it; there is only one way to do it. The work forms or flow sheets or whatever you want to call them may vary a bit, but they all have to get you the same four things: Ho, Hc, intercept, LOP.

Modern-day practice is to use the Nautical Almanac, Sight Reduction Table 249 and the VPOS Universal Plotting Sheet. You're familiar with all of these from the Starpath course. I'd be very surprised if ASA uses anything else, but you should be able to find out what Almanac, Sight Reduction table and Plotting Sheet they are going to present you with (or expect you to show up with). If you ask, I'd think they would send you a copy of their work form. Maybe they would allow you to use the one you're familiar wih - Starpath's.

Since you've got the book of exercises, try one of its problems with the Starpath form, then do the same problem with the book's form. Each form has to contain the same four steps and has lead you to the exact same result. That's the only way celestial works.

David Burch

 - posted September 12, 2007 04:58 PM      Profile for David Burch           Edit/Delete Post 
It is also valuable to take the starpath certification test before doing the ASA or US Sailing tests. It is good practice and it covers the same types of problems. The fee is $30.
From: Starpath, Seattle, WA

 - posted September 18, 2007 05:03 AM      Profile for DustyDan           Edit/Delete Post 
From: North Dakota

 - posted October 02, 2007 11:30 AM      Profile for DustyDan           Edit/Delete Post 
I believe the book used NAO format. Note getting along well with that. I'll order the test from you folks. Thanks.
From: North Dakota

 - posted October 02, 2007 02:11 PM      Profile for HHEW           Edit/Delete Post 
I'm not familiar with the NAO form, but the main thing is you're practicing and that's all to the good.
David Burch

 - posted October 02, 2007 06:01 PM      Profile for David Burch           Edit/Delete Post 
I would guess that most schools offering the ASA certification test do not care what set of tables you use, nor what work forms. This would be easy to find out by just asking them.

for a certification test, i would use the pub 249 tables as we use in the course here, but the question would be the stars. we do not much emphasize the use of the star tables for 249, but if you are relying on 249 alone then it would be best to review the use of vol 1 on selected stars.

ie... do all the star sights again that we have in the course but use vol 1, rather than the vol 2 as we do.... or if you need more problems let us know and we can tell you how to make unlimited practice with modern skies.

the key is to ask the school. usually they also provide the tables they want you to use if they have a preference.... also be sure to take your star finder.

From: Starpath, Seattle, WA

 - posted October 09, 2007 10:38 AM      Profile for DustyDan           Edit/Delete Post 
The school tells me they will bring Pub 229, and I have no experience with this publicatino (Maryland School of Sailing). Guess I'll have to order it. Wonder if Tom Tursi has this preference. Seems he's the guru.
From: North Dakota

 - posted October 09, 2007 12:26 PM      Profile for HHEW           Edit/Delete Post 
Publication 229 is called "Sight Reduction Tables for Marine Navigation" and consists of 6 volumes, each about the size of a volume of 249. Unlike 249 where only declinations 0-29 are covered, 229 covers 0-90, so there is no separate volume for stars. The increase in the range of declinations is the main reason for the extra bulk of 229.

Like 249, 229 is an inspection table - you look up Hc, d, Z. 229, however, gives these values to the tenth of a minute so interpolation is lengthier. There is also an interpolation procedure called "double second difference" to cover instances where the Hc is not changing linearly. (This might be included on the test)

The layout of 229 differs from 249 in that the initial entry is by LHA not Lat as you are used to in 249, and the declinations run down the side of the page where you are used to finding LHA; Latitudes run across the top of the page where you are used to seeing Declinations.

You can get a look at 229 and even print pages from it at

One way to get familiar with 229 might be to use it do some of the problems you've already done in the Starpath course and have the answers to.

David Burch

 - posted October 09, 2007 08:26 PM      Profile for David Burch           Edit/Delete Post 
another note of follow up.

If they want you to use 229 and they are brining it for you then you are covered. the tables are easy to use and we have instructions for them in our own forms because our forms work for them as well. need to find out if they will let you use our forms.

also you do not need to buy the tables to practice since you can download them from the Internet. see http://www.starpath.com/navpubs.

just work a few examples that you already have worked with the new 229 tables and you will be ready to go.

* * * I want to stress the value of taking our certification test before taking the ASA or US Sailing tests. You could also work it with 229 if you choose using the download edition.

Pub 229 is not really the preferance of any particular organization. the USCG requires their endorsements tests done that way or with the NAO tables. To my knowledge the ASA does not care what set of table you use. most navy cel nav is done with a computer program called stella.

most cruising sailors use Pub 249 or a calculator.

From: Starpath, Seattle, WA

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