NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Bill Ritchie
Date: 2024 Feb 9, 02:10 -0800
Hello Murray,
You quote Maskelyne's explanation to the 1767 Nautical Almanac "The Eclipses of Jupiter's Satellites are well known to afford the readiest, and for general Practice the best Method of settling the Longitudes of Places at Land”. So discussion on Jupiter’s satellites must be relevant to navigation, and not out of context for NavLIst!
The archive link you gave to the 1767 Nautical Almanac yields a treasure of information. Thank you for posting it. I was particularly interested in both the Almanac’s tables of times of eclipses of Jupiter’s satellites and the schematic drawings of the satellite apparent daily positions at 2300.
Astron’s phase image cell also shows the satellite apparent positions, at any user selected date and time. The attached screenshot extracts for 2300 on 2nd January 1767 are interesting to compare. (Orientated as would appear from 40N 090E).
However, I have not included any satellite eclipse data.
So I now ask if anyone would find it useful (or just interesting) if I were to add the times of all eclipses of the Galilean satellites for the currently entered UT day? It would be part of the existing mouse over pop-up, so would not take up screen real estate. Tables of predicted times of such eclipses for (say) 2024 are available from several online sources, but I cannot find any utility that lists the eclipse times for any user chosen date, such as January 2nd, 1767.
Thank you again for listing this classic 1767 Almanac archive.
Bill Ritchie
