The Caldwell Catalogue

By Malcolm Gibb

A short time ago somebody asked me about the Caldwell Catalogue and although I new what it was and who originated it I didn't know why. I decided that the best person to ask about it was the originator, Sir Patrick Moore. Sir Patrick, being the gentleman that he obviously is, replied within a week. The following letter is the result…

Dear Mr. Gibb,

I have to say that the Caldwell Catalogue began because I had just finished writing up my latest observations of Mars, and had a bit of spare time!

For fun I had looked at some nebulae, including those not listed by Messier. Of course we all know that Messier was not in the least interested in nebulae, but listed only those that could be confused with comets. So why not list those he left out, and extend it to the far south? Idly, I began doing so, and in a couple of hours I had made a list of 109 objects.

That was about 'it', but on impulse I sent it to SKY AND TELESCOPE, thinking it would amuse them. To my astonishment, they took it up, and before long the Caldwell numbers had come into wide use! Two books have been planned about them (not by me) and one has already come out. It took me by surprise! People seem to find it useful, the only sour note came from a Mr. Owen Brazel, who didn't approve of it (I can't help wondering if he was irritated at not having thought of it first!).

Why Caldwell? Well, clearly I couldn't use M, and my surname is actually Caldwell-Moore, so I used the C.

Best wishes to you all.

Signed by Patrick Moore

As Sir Patrick states, Messier was only concerned with objects which could be confused with comets, in which he was very interested, but it is ironic that he is best remembered for the catalogue to which he gave his name and the numbers are still in use today.

The original of the above letter is in the AFA information book .

A list of the Caldwell objects can be seen on wikipedia.