Mike Coon wrote on 9/1/2017 6:17 PM:
In article , says...

There are two basic units of time; the day and the year. Those are
astronomically defined. ...

Except IIRC the "day" is ambiguous astronomically is you don't
distinguish solar day (in usual parlance, e.g. between the sun being due
south) and stellar with the stars returning to their same positions
overhead. These two have to have a difference that adds up to a whole
day over the course of the year.

Is that a solar year or a sidereal year?

--

Rick C

Viewed the eclipse at Wintercrest Farms,
on the centerline of totality since 1998