On Saturday, December 1, 2018 at 4:46:52 AM UTC-7, Gerald Kelleher wrote:

The Martian Lat/Long system then fits inside this framework where the 24 hours 40 minutes

And, indeed, the Martian day - the solar day, which corresponds to the 24 hour
solar day on Earth - is 24 hours, 39 minutes, and about 35 1/4 seconds.

Whereas stellar circumpolar motion on Mars has a period of 24 hours, 37 minutes,
and about 22 2/3 seconds.

I was looking for an accurate value for Martian circumpolar motion - I thought I
had that on my site as well, and I did, but I just looked in the wrong place -
and found *this* web site...

https://www.windows2universe.org/kids_space/period.html

which says

" Earth's day (or rotational period) is exactly 23.9345 hours (or, 23 hours, 56
minutes, 4.2 seconds)."

If that were true, I would have to set my watch back four minutes every day.
While I disagree with you in that I think that there are good and proper reasons
to view the period of stellar circumpolar motion as the true period of the
Earth's rotation, I know very well, from the natural cycle between light and
dark, warm and cold, that a _day_ on Earth is 24 hours long.

I blame people like them getting the day wrong for the confusion in which you,
in reacting to their error, have placed yourself.

John Savard