Hello Bill,

> Guide has one misbehavior and one bug here. The "misbehavior" is
> reporting "mag 99.0" instead of "no magnitude available", and I've
> just fixed this.

that's fine. Will it then be shown when the mag limit is set to a fixed
value (say 17 mag)? This would be preferable.

> The "bug" involves how it shows comets without magnitude parameters.
> The head and tail size are determined using formulae kindly supplied by
> Andreas Kammerer, as described at
>
> http://www.projectpluto.com/update7b.htm#comet_tail

As you write this I remember deep in my brain that there was a
discussion about that topic.

> When there are no mag parameters, I've been feeding Andreas' formula
> an absolute magnitude of zero, meaning a _very big_ comet. The next
> update I post will use an absolute magnitude of 10 in such cases, i.e.,
> a pretty faint comet. That way, you will still see a tail, and its
> position angle will be meaningful, but it won't be an unrealistically
> huge head and tail such as you are seeing now. (And when you click on
> the object, you'll see "No magnitude available", so you will know not
> to trust the tail length and head size very much anyway.)

As a suggestion, wouldn't it be better to take the mean (or median)
value for the absolute magnitude of comets of that time (I mean pre-CCD
and pre-survey)? I believe most of that comets were discovered visually
and were rather bright, compared with todays LINEARs and NEATs of mag
17 to 19 (apparent brightness).

Thanks for your quick reply and keep on improving this great program.
Clear skies
Bernd

Bernd Brinkmann
Sternwarte Herne, MPC code A18

http://www.sternwarte-herne.de
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