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» Online Classroom   »   » Public Discussion of Cel Nav   » stars with declination above 29 degrees

Author Topic: stars with declination above 29 degrees

 - posted March 20, 2009 12:05 PM      Profile for Roger           Edit/Delete Post 
While working problems in 101 Problems in Celestial Navigation by Gray I often encounter sight reductions of stars which have declinations above 29 degrees. How do I enter H.O. 249? What am I missing? Thanks Roger.

 - posted March 20, 2009 12:52 PM      Profile for HHEW           Edit/Delete Post 
Using 249 vol. 2 or vol. 3, you can't. As you've discovered, these two volumes of 249 only give Hc's for bodies with declinations to 29° North and South.

To reduce stars with higher declinations in the way you're used to - i.e., with a pre-coomputed inspection table, you'll need Pub. 229. There are six volumes to 229, each covering 15° of latitude.

229 covers all declinations. The main difference in usage is your first opening of the table is LHA, not LAT. Then, you'll find the Latitudes across the top row and the Declinations in the vertical columns on the left and right. Left-hand pages cover SAME Name, right-hand CONTRARY Name.

David Burch

 - posted March 20, 2009 01:15 PM      Profile for David Burch           Edit/Delete Post 
we have the Pub 229 on the course CD or you can download it from www.starpath.com/navpubs

also you can use the NAO tables, which we have online in the Library or they are included in each copy of the Nautical Almanac.

Note to that we now carry printed copies of all of the Sight Reduction Tables.

From: Starpath, Seattle, WA

 - posted March 20, 2009 02:32 PM      Profile for Roger           Edit/Delete Post 
My sincere thanks. I plan to begin getting familiar with 229 this very day. Thanks Roger

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