Re: [guide-user] Quick Info - Asteroid opposition date

alfredo caronia Aug 31, 2012

Thank for your info and advice!


Il giorno 31/ago/2012 15:53, "Bill J Gray" <pluto@...> ha

> **
> alfredo caronia wrote:
> > As user of Guide 8 , i will know how it is possible to calculate
> > date of opposition for any asteroid for any year!
> At present, at least, Guide doesn't do this directly. The best
> one can do is to click on an asteroid and make an ephemeris, then
> search that ephemeris for an opposition date.
> You then run into the odd problem of what an "opposition" is. Does
> it mean the object is 180 degrees from the sun in ecliptic longitude?
> Or in right ascension? Or does it mean the object's elongation is at
> a maximum? Or maybe maximum magnitude? All of these definitions
> have their proponents.
> The differences are of minor importance for planets, because their
> orbits are pretty much in the same plane as the earth's. They loom
> larger for asteroids, which can have very unusual apparent motions
> as seen from earth.
> -- Bill

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