Stacy Jo McDermott wrote:
[snip]
> M40 in Ursa Major - [snip] Pretty non-descript as far as
> doubles go. Pretty equal in brightness and colour. How Messier
> thought that people would confuse this with a possible comet is a
> mystery probably never to be solved.
No mystery. Messier described it as a double star. Hevelius had
reported a suspected nebulosity at this spot. Messier saw no
nebulosity, but assigned a number to the double, saying "... in
Hevelius' memory."
So there IS a mystery. What fooled Hevelius?
-- Jim Van Nuland, San Jose (California) Astronomical Association <a href="http://www.svpal.org/~jvn/ ">JVN's web site</a>