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Re: Haversine- how to derive it?
From: Samuel L
Date: 2015 May 18, 17:36 -0700
4. calculate n + ( 1 - q ) * hav ( LHA ); this yields hav ( ZD )
From: Samuel L
Date: 2015 May 18, 17:36 -0700
Hanno,
I tried a reduction using the Haversine method Greg lists (for Deneb) on his s/v Nightcap site (http://gregrudzinski.blogspot.com/)
I deteremined Hc with not too much trouble but can't figure out how to calculate Zn. He shows 360d - 16d= 344
Would you, or Greg, please explain how to determine Zn....in very simple terms?
Thank you,
Sam L.
However, using the haversine G. Rudzinski and I can show you another,
very easy calculation of Hc. Only one table, 2 pages, is used and only one
multiplication is needed. There are no complicated sign rules
and special cases - it will work for all permutations of L, d and LHA.
very easy calculation of Hc. Only one table, 2 pages, is used and only one
multiplication is needed. There are no complicated sign rules
and special cases - it will work for all permutations of L, d and LHA.
Given: L, d, LHA, find Hc. Execute these 6 elementary steps:
1. calculate n = hav ( L - d )
2. calculate p = hav (L + d )
3. calculate q = p + n
4. calculate n + ( 1 - q ) * hav ( LHA ); this yields hav ( ZD )
5. find in table ZD by looking up the table backwards
6. Finally Hc = 90 deg - ZD
As can you see the steps are basic arithmetic - executable by hand in minutes.We discussed all this on the list under the topic Longhand Sight Reduction.
For the azimuth we suggest using the azimuth table I published there, too.
H
