NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Paul Jackson's Luna data
From: Peter Hakel
Date: 2010 May 11, 23:41 -0700
From: Peter Hakel
Date: 2010 May 11, 23:41 -0700
I expand a little bit on some of the points raised earlier by George.
In the data the refr+parlx for Moon has the wrong sign: c_Moon should be positive 48.4', then hc = 22 deg 10.7'.
Jupiter's correction also has the wrong sign displayed but somehow there the hc comes out right.
I get da = 7 deg 36.9' which agrees well, but then my dc = 7 deg 31.7', so there is something going on with the clearing calculation. In my references the ha (apparent altitude) does not include the semidiameter correction, whereas this program does include it in ha. Different conventions, nomenclature?
On another note, I do notice that at the stated time of observation Moon and Jupiter are nearly on the same meridian (GHA ~ 145 degrees). Indeed, one can see that the observed lunar distance is roughly the same as the sum of the absolute values of the two declinations. Could this limit the practical utility of a lunar?
Peter Hakel
From: Paul Jackson <pw.jackson@xtra.co.nz>
To: NavList@fer3.com
Sent: Tue, May 11, 2010 4:22:09 PM
Subject: [NavList] Paul Jackson's Luna data
In the data the refr+parlx for Moon has the wrong sign: c_Moon should be positive 48.4', then hc = 22 deg 10.7'.
Jupiter's correction also has the wrong sign displayed but somehow there the hc comes out right.
I get da = 7 deg 36.9' which agrees well, but then my dc = 7 deg 31.7', so there is something going on with the clearing calculation. In my references the ha (apparent altitude) does not include the semidiameter correction, whereas this program does include it in ha. Different conventions, nomenclature?
On another note, I do notice that at the stated time of observation Moon and Jupiter are nearly on the same meridian (GHA ~ 145 degrees). Indeed, one can see that the observed lunar distance is roughly the same as the sum of the absolute values of the two declinations. Could this limit the practical utility of a lunar?
Peter Hakel
From: Paul Jackson <pw.jackson@xtra.co.nz>
To: NavList@fer3.com
Sent: Tue, May 11, 2010 4:22:09 PM
Subject: [NavList] Paul Jackson's Luna data
Here are the data sheets that I said I would post to Nav list
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