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» Online Classroom   »   » Public Discussion of Cel Nav   » Text Example on Page 96

   
Author Topic: Text Example on Page 96
climber


 - posted June 06, 2019 12:37 PM      Profile for climber           Edit/Delete Post 
On page 96 of the text, in the example for Venus, the LHA for Venus is determined to be 92 degrees.
I use H.O. 229 and the tables do not include an LHA of 92 degrees.
I took this course several years ago and am reviewing to hone what skills I still have. For the life of me I cannot remember how to find the Hc, d, and Z values for an LHA of 92 using H.O. 229. No matter what approach I take I cannot duplicate the values in the example.
The basic question is: For an LHA of between 91 degrees and 269 degrees, how is H.O. 229 used?
I'm sure the answer is obvious but I certainly cannot figure it out.

Thank you.

From: apalachicola
Capt Steve Miller


 - posted June 06, 2019 02:07 PM      Profile for Capt Steve Miller           Edit/Delete Post 
HO Pub 229 does have LHA between 90* and 269*. You will find those LHAs note at the bottom of the page.
Looking at 229 Volume 3 page 361 at the bottom of the page to the far right you will see LHA 92*, 268*, you will also see Latitude SAME name as Declination. Then looking at the column for 45*S Latitude and the row for Declination 24* S, at the intersection you will find - Hc 15* 22.2', d +40.8, Z 71.2*. You would continue as normal for the rest of the reduction using 229.

From: Starpath
climber


 - posted June 06, 2019 02:27 PM      Profile for climber           Edit/Delete Post 
I knew there was a SIMPLE answer to the question. This is a primary example of the dangers of tunnel vision and the saying “Insanity is doing the same thing over and over again while expecting a different result”. You get locked into one way of looking at things and don’t see the obvious. Flexibility and adaptability are the keys to survival, and navigation.

Anyway, thanks. I can’t believe I missed it, but I did.

From: apalachicola
climber


 - posted June 06, 2019 03:03 PM      Profile for climber           Edit/Delete Post 
OK, now that I’ve got that, let me ask another question. What do you do when you have an LHA of 92 degrees and a declination of 24 degrees N while your latitude is south (or vice-versa) - a “Contrary” situation? I don’t see any way to address this situation as the 92 degree page is all “Same” up to the C-S line.

I am thinking that the C-S line is key here but I’m not sure.

From: apalachicola
Capt Steve Miller


 - posted June 06, 2019 06:52 PM      Profile for Capt Steve Miller           Edit/Delete Post 
Upon looking at both 229 and 249 it appears that there is NO solution to that scenario, The body is most likely below the horizon therefore an invalid situation.
From: Starpath


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