Alan,

I think the argument of perihelion is the most important factor here. This
is the angle between point of perihelion and the point where the object
crosses the ecliptic (asc/descending node). Now this latter point could be
anywhere - 0.3AU, 2AU or 300AU.
If there was a way of working out the distance of these nodes from the sun
and if these distances were near 1AU then we would have a PHA.

A bit of trig may come in handy - but I haven't done trig for ages. I'll
keep searching.

Any maths nuts out there?

Cheers
James

Ps Australia just scored 337 against Pakistan in 50overs.... yeahhh

>Thanks James,
>I have to admit, I don't understand the maths in this, but I do think it
>would be a useful display.
>Any help would be appreciated
>
>Cheers
>
>Alan
>--
>Alan Cahill

"An elephant : a mouse built to government specifications"
(or vice versa)