NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Planet positions and light travel time
From: Mike Mayer
Date: 2017 Dec 17, 16:52 -0600
From: Mike Mayer
Date: 2017 Dec 17, 16:52 -0600
I’ve written ephemeris software and one of the things you do is use the distance to the planet to account for the light travel time and calculate the apparent position of the planet.
mwmayer@tds.net
From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of David Pike
Sent: Sunday, December 17, 2017 3:34 PM
To: mwmayer@tds.net
Subject: [NavList] Planet positions and light travel time
I only just thought of this, and I wish I hadn’t, because the answer will probably make me look very dim, but how do the tables allow for the fact that when you observe a planet, the light you see comes from where the planet was several minutes before, not where it was at the time of observation? DaveP
