A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Adrian F
Date: 2020 Apr 9, 03:50 -0700
I’m only a newbie on this board, but might I be allowed to comment on the specific ISS suggestion please?
It looks from the data on the Heavens-Above site that ISS can reach a maximum altitude of about 69 degrees when seen from central England so could fit the “high in the sky” description. However I think from there it would always appear to be moving right to left in the sky rather than left to right. I’m to the North of the maximum latitude that ISS reaches (about 51.64 degrees) and I know David is as well.
If ISS data was to be compared from one day to another I believe that – at the moment -comparing ISS data for April 10th would be more useful than data for the 9th, assuming David saw the object on the 8th. In general a given day’s ground track of a satellite can be different to the next day. I think it’s because a satellite doesn’t necessarily make an integer number of orbits in the 24 hours.
At the moment, the ISS’s ground tracks seem to be fairly similar at 48 hour intervals. From where I live there are ISS passes predicted on Heavens-Above for 15:20:05 on the 9th April, at 15:22:28 on the 11th, and 15:24:47 on the 13th but nothing around those times on the intermediate 10th and 12th. I’m guessing the approximately “48-hour cycle” at the moment may come from the number of orbits ISS makes in 24 hours being close to a “half-number”, 15.4872 orbits at present.