Which of the Visible window's four conditions changed at one of its ends,
so that a caller can say why the Satellite appeared or disappeared: it rose
past or dropped below the rule's elevation (elevation), left or entered
the Earth's shadow (sunlit), the sky darkened or brightened past Night
(night), or it brightened or faded past the threshold (brightness).
When two change within the same fraction of a second, the first of that
order is reported.
Which of the Visible window's four conditions changed at one of its ends, so that a caller can say why the Satellite appeared or disappeared: it rose past or dropped below the rule's elevation (
elevation), left or entered the Earth's shadow (sunlit), the sky darkened or brightened past Night (night), or it brightened or faded past the threshold (brightness). When two change within the same fraction of a second, the first of that order is reported.