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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Herman Dekker
Date: 2023 Aug 26, 03:39 -0700
Is it possible to calculated the HourAngle HA , input Lat, Dec, Ho with use of the Ageton Classic (12 pages) table?
This compact table works fine for calculating Hc and Z.
As long you can understand the (not specified) rules for reading this table.
There are many ways to wrongly reed this table, I have written down a few rules for myself to make it easyer.
1. In the degees colums, reed these with as basis the whole degrees from one of the four corners
and then ALWAYS AD (+) the minutes from the column under or above the basis degrees you used.
For me it feels normal to AD as you scroll up or down in a increasing values column.
But is feels wrong to AD as you scroll up or down in a decreasing values column. Anyway ALWAYS AD (+)
the minutes.
2. If you use the whole degrees from top header reed the colums from left to right as Sin-A-B-Cos.
If you use the whole degrees from the bottem footer reed the colums from right to left as Sin-A-B-Cos.
3. From Sin or Cos value to Degree value, reed the degrees from the column nearest to the Sin Cos coulm
you use.
4. Remember the calculated height Hc must be between 0° and 90°. Ignore the values above 90°.
Compleetly logical for most people, but i managed to reed it wrong a few times.
Question: How to solve HA=cos-1 {(sinHo - sin Dec·sin Lat) / (cos Dec·cos Lat)} with the Ageton Classic table.
See attached AgetonClassic table. (Design idea from Greg Rudzinski)
Greetings,
HermanD