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» Online Classroom   »   » Public Discussion of Cel Nav   » Stark Tables/log Dec tables (p.275/291)

   
Author Topic: Stark Tables/log Dec tables (p.275/291)
clarkj


 - posted June 04, 2019 10:49 AM      Profile for clarkj           Edit/Delete Post 
Dear Sirs:

I have Bruce Stark’s book. I am trying to work through the examples. Do you know how the log Dec tables (p.275/291) are derived? Table 8 for instance is log10[60/min] and Table 7 is log10[240/min]. I can’t figure out a similar arrangement for log Dec.

Best Regards
Jeremy Clark
Toronto, Ontario, Canada

From: Toronto
David Burch


 - posted June 06, 2019 12:44 PM      Profile for David Burch           Edit/Delete Post 
I apologize for the delay. we are held up here on a couple projects, but i will try to address this today.
From: Starpath, Seattle, WA
David Burch


 - posted June 06, 2019 03:27 PM      Profile for David Burch           Edit/Delete Post 
I can't quite figure this out yet from scratch, but there are quite a few articles by Bruce and Jan Kalivoda on the Stark Method in the Navigator's Newsletter. ( https://www.starpath.com/foundation/index.htm )

Index is here
https://www.starpath.com/cgi-bin/newsletter/nav_news_index.pl

the volume with most of the articles is here

https://www.starpath.com/foundation/NN-vol-2.pdf

Another way to get your answer is to post a question in nav list online discussion forum at www.fer3.com There are many lunar experts there, many of whom are familiar with the Stark Tables.

Failing both of those, we would have to go back to the basic procedure he is using and reverse engineer it from there.... i notice in Bruce's writing about this he refers to it as "a log-dec value," as opposed to "log 10 of the declination," which it is not.

From: Starpath, Seattle, WA
clarkj


 - posted June 06, 2019 05:40 PM      Profile for clarkj           Edit/Delete Post 
Thanks David I will check out the articles you mentioned. It seems to me that similar to table7/8, it should be some form of normalized log table. I will dig further...
BR/Jeremy Clark

From: Toronto
clarkj


 - posted June 09, 2019 03:05 PM      Profile for clarkj           Edit/Delete Post 
I posted on Navlist and got a quick reply. Bruce Stark describes his table construction in a posting May22nd/2003. The table is the negative of the log10 of the cosine of the angle. For example:

angle = 29deg 18.6min, cos(angle) = 0.871983845, log10(cos(angle)) = -0.05949156, log dec table page 291 = 0.05949

From: Toronto
David Burch


 - posted June 09, 2019 04:58 PM      Profile for David Burch           Edit/Delete Post 
Excellent. The NavList is an excellent resource for the nuances of celestial navigation.
From: Starpath, Seattle, WA


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