Bill,
For me its enough just to know the PA (Position Angle) of comet.
Patrick Stonehouse
C/1998/H1



--- In guide-user@yahoogroups.com, "Mark S Deprest" <msdeprest@c...>
wrote:

>
> Bill,
> If you could figure a way to show that, you would have another

first

> in astronomy software, and I know a whole lot of comet crazies

like

> myself that would be totally blown away!
> Tail orientation of comets is a very difficult thing to get right,
> mostly because ... as David Levy says, "Comets are like cats, bith
> have tails and both do exactly what THEY want to!"
> Thanks Bill, for responding to this topic!
> Mark S Deprest
>
> --- In guide-user@yahoogroups.com, Bill J Gray <pluto@p...> wrote:
> >
> > Hi folks,
> >
> > Sorry for the long silence! I've come back to find a large
> batch of
> > e-mails; I should be clearing the backlog in a bit.
> >
> > Guide just shows the tail pointing away from the sun, which

is

> > usually a good guess. It's been suggested to me that the ion

tail

> > usually points away from the sun, but that the dust trail

usually

> > points along the line of variation. (That is, solar radiation
> pressure
> > knocks off the dust and pushes it out slightly; that results in
> the
> > dust grains traveling along the same orbit as the comet, but
> gradually
> > falling behind it.)
> >
> > Dunno how much truth there is to this. I'll probably try it
> out at
> > some point; if it works, Guide could show both the ion tail

_and_

> the
> > dust tail, and probably even a dust tail with the right curve.
> >
> > -- Bill
> >
>