Robert wrote:
> This one involving magnitude:
> 
> If a star has a parallax of 0.1 seconds of arc, and an apparent magnitude of 
> 3, what is its absolute magnitude?  Apparently the answer is 3, but I have 
> no idea why.  Can anyone show the simple work?

Its worth remembering that usenet and www are not a good substitute for 
a text book. You should invest in a book.