Mark S Deprest wrote:

> Thank you Kevin,
> I checked all of that info before writing the group and the inverted
> telescope theory does not work either because that doesn't explain
> the star positions. (see Photos section for this group) The image was
> taken by Mike Holloway at 00:00UT on 12/31/05.



> --- In guide-user@yahoogroups.com, Kevin Cooper <kevinjcooper@d...>
> wrote:
> Mark,
> Comet tails point away from the sun My Guide 8 shows the comet tail
> trailing to the NE at an angle of 69 degrees. The angle from the
> comet to the sun is 240 degrees. 180 from 240 gives 60. This give the
> tail trailing 9 degrees off 180 degrees from the suns direction.
> Therefore, if the comet's position is correct, the tail orientation
> is correct within reason.

There can be a logical answer to the problem and one that Guide does not
account for.

First the Sun and Comet McNaught are about 45° apart in our sky.
Second the Comet is more than twice as far away as the Sun.
Thirdly the Comets motion is directly opposite the direction the tail
is pointing (to the upper left in the photo)
Forth the comet is almost exactly on the ecliptic and moving parallel to
it and perpendicular to our line of sight, so we are seeing the comet
tail almost edge on.
.
Now if you think in three dimension the comet tail would be severely
forshortened because our view of it is somewhat less than 45° because
the comet is so much further away than the Sun (likely close to 22.5°)
In fact I just used Guide to get a view from the Comet and the angle
between Earth - Sun is 24°.
The motion of the comet perpendicular to our line of sight could cause
that much deflection of the comet tail.

Now I'm not sure if even Bill can build that into the program :-)

Larry Wood