CdM - Daylight Savings Time? (I know it's not right (named after a person?) but the audience reaction might be helpful...)*the audience shrug their shoulders* No
Dujon - A full moon? *appreciative murmurs in the audience* This is sometimes contained in the answer
Software - St Elmo's Fire? A wonderful Eno song, but not the answer

A summary?

Shut up, dickybirds, I'm trying to get to sleep.

Kim] Is it Keith Moon? No, nor Freddy Mercury either ;-)
Rosie] The dawn chorus? Oh don't deceive me, oh never leave me, how could you treat such a poor maiden - no

A summary

You’re looking for an ABSTRACT with MINERAL and ANIMAL connections. The animal connection is human. It is named after a particular person (for a given value of ‘person’). It doesn’t have a physical manifestation, though it is (arguably) observable in nature, and in that sense visible with the naked eye. It is inside the solar system. The closest guesses so far are that it is related to astronomy, related to the movement or path of some celestial object, and related to the rising or setting of some astronomical body. You might want to think about the scope of the word ‘related’. ‘Dawn’, ‘twilight’ and ‘a full moon’ also received some applause. It is also scientifically valid/viable/real/true (though some of these are more applicable than others).

It does not begin with S, or with a vowel. It is not (leaving out guesses ruled out by the above): a meteorological phenomenon; a collection of objects; an aura; anything to do with astrology; the conjunction of Venus and Mars; the ecliptic; an apogee; a transit of Venus; the Clarke orbit; the Kirkwood Gaps; the Van Allen belts; a feature of the Earth’s surface; the Trojan points; gravity; celestial co-ordinates; Oppolzer's Canon of Eclipses; a form of electro-magnetic effect; the Kuiper belt; the intersection of two or more things (well, you could describe it as that, but it wouldn’t be useful); a light-year or a parsec (though these have something in common with the answer); a name or description of the path of a celestial object; an Astronomical Unit; Kepler's laws of planetary motion; related to navigation; the man in the moon; the precession of the equinoxes; tidal patterns; atmospheric refraction; related to a shadow; the Green Flash; Daylight Savings Time; or St Elmo’s Fire.

It is much simpler than most of these. Much, much simpler. You will kick yourselves (you would probably also kick me, for sounding so smug…) Dujon’s definition of “something that changes from moment to moment even though retaining its description” is the closest so far, though my prediction that this wouldn’t be helpful hasn’t been proved wrong yet.