A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Position-Finding
From: Frank Reed
Date: 2017 Dec 5, 08:08 -0800
Ed Popko, you asked:
"is there any reason that when Object is Moon and any Limb is selected, the main panel always says Moon (Hc)"
It's below the horizon (that's the case in the eastern USA right now, as I write this). The app works out the sextant altitude based on the horizon type, and if that ends up less than zero, then it reverts to a geocentric "Hc" value. It could just as well display nothing --since you can't see the object!-- but the Hc choice gives you some dancing numbers to watch :).