NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Bill Ritchie
Date: 2021 Nov 5, 15:42 -0700
Peter,
I don't think there is any query that ICE calculates the positions for the body centers. It is for which limb (or center) the refraction correction is calculated.
Object GHA Dec Hc Zn Refr SD PA Sum
SUN 359 59.3 s16 07.3 +73 52.7 180.0 -.3 16.2 .0 15.9
In the above example you quote, the SD correction (applied to Hs) of +16.2 must be for a lower limb sight. Surely, therefore, the authors would have used the refraction for that same limb? The last definition that you quote (below) is consistent with this.
"If Sum is subtracted from Hc, the apparent altitude (that comparable to observation) of the lower limb of the object is obtained."
Bill Ritchie.
