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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Doing my homework
From: Stan K
Date: 2016 Nov 3, 18:52 -0400
From: Stan K
Date: 2016 Nov 3, 18:52 -0400
Tony,
The only notable difference is that Celestial Tools uses the nearest tabulated value for t and Dec, without interpolation, which is the way the Ageton tables are expected to be used, judging from the examples in the H.O. 211 book.
You might consider using Celestial Tools to check your work. Here is the Ageton output for your problem:
Stan
-----Original Message-----
From: Tony Oz <NoReply_TonyOz@fer3.com>
To: slk1000 <slk1000---.com>
Sent: Thu, 3 Nov 2016 18:05
Subject: [NavList] Re: Doing my homework
From: Tony Oz <NoReply_TonyOz@fer3.com>
To: slk1000 <slk1000---.com>
Sent: Thu, 3 Nov 2016 18:05
Subject: [NavList] Re: Doing my homework
Dear John,
Thanks for reassuring me! :)
Yes, one can/should have a quick look at his compass for the azimuth estimation. But for now I would consider that as cheating. I'd like to understand the basics of it.
I do understand that Jupiter was to the east of me, so t should be positive. May be this is just a quirk of the work-sheet since it is not official after all. The work-sheet and all the tables are "homebrew", so to say.
So, the lesson I must take from this is: to always calculate LHA counting from me to an object WESTWARDS. I.e. - LHA is not an arithmetic summ of GHA with LonAP.
Now back to the given work-sheet: since LHA is nowhere actually used - the step 1 should probably be re-phrased to calculate t from GHA and LonAP respecting +/- sign of LonAP operand. Then in my case t would be positive and I get the correct Zc in step 8.
Thanks again!
Warm regards,
Tony
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