Going back to my first question - 'relates to the movement or path of a celestial object' (answered YESish) and assuming that your last answer excludes all man-made celestial objects.
Is the anwer the name or description of that path?

Raak] Is it the intersection of two or more things? You could at a pinch define it like that, but it wouldn't be very helpful.
Kim - Is it visible with the naked eye? Bearing in mind the earlier qualification of 'observable', yes.
Chalky - A light year - or ... a parsec? Inside the solar system? However, a modicum of *applause* for these having something in common with the answer.

INJ] Good question, but no (and your assumption is correct)

Raak] An Astronomical Unit? No
Rosie] The rising or setting of some astronomical body? *applause and some cheering* Related to, yes.
Quendalon - Kepler's laws of planetary motion? No
ImNotJohn - Is it related to navigation? No

silly guess - I know :-)

Chalky]The man in the moon? No - but it would have been a good one ;)
Raak] www - the world-wide wobble? No
Phil] Tidal patterns? No
Rosie - Atmospheric refraction? No

... a one-word answer will suffice ;-)

Quendalon - Dawn? *some applause* No, but getting warmer...
Chalky] OK - Is this 'man's' [the animal] perception of something that occurs in our universe [abstract] - meaning, does he need something [mineral] in order to 'see' or 'interpret' this thing [which is abstract]? ... a one-word answer will suffice ;-)

No >:)

ImNotJohn] The shadow? Noes
Raak - The Green Flash? *Before Googling* No *After Googling Well, there you go - I've never seen one of those.
Rosie - Twilight? *applause* For the same reason as Quendalon - both of those are necessarily contained in the answer.