M102 whats with the ?

[Doc]

Can anyone tell me why M102 a galaxy in Draco has a question mark next to it in Cartes du Ceil.

[Psychobilly]

I wonder if this is why...

Messier Object 102

Peter...

[Doc]

I wonder if this is why...

Messier Object 102

Peter...

Cheers Peter thats very interesting I'm off to investigate some more.

[dobserver]

It's not included in the Messier index in The Pocket Sky Atlas - Reece pointed that out to me last night.

[acey]

The non-existent M102 poses a question for anyone attempting to see all the Messiers. Do you take it as a "free object" on the way to a total of 110, or do you eliminate it from what is really a list of 109 objects? Or do you go for, e.g., NGC 5866 as standing for M102? Given that this is Messier Marathon week it's a topical question. Personally I went for 109 as the target number, which is also the number that Patrick Moore chose for the Caldwell list. In any case, some of the last Messier entries weren't put there by Messier himself, so it's all a confusing historical morass - well explained in O'Meara's fine book.

I use 109 in the observing tally in my signature but I notice that quite a few people who are currently working through the Messiers use 110. Evidently they're going to bump into the same quirk that you've noticed, Mick.

Andrew

[Capricorn]

As I recall M102 was "withdrawn" as being a duplictae of M101.

The problem being that the "withdrawl" was supposed to have been made at a body in Austria (possibly wrong) and Messier had never had anything to do with this body. He had always published his work elsewhere - France.

Additionally there was questions about the details of what was being withdrawn anyway.

The problem hinged on the apparent positions. Seemingly M101 and M102 had the same position - hence being a duplicate. However the diagram drawn by Messier, or his assistant, didn't match. M102 was a very different diagram to M101. Also there was some doubt about the way the "withdrawn" object was specified. Basically something was wrong.

Unfortunately I suspect that Messier died before it was sorted out.

Later this missing Messier came up again and people started looking into it. The general, and only general, opinion was that the object described matched with NGC5866 in Draco.

If I recall I found this from a site called SEDS or similar, probably traced through wikipedia. It made interesting reading.

So you have 2 options, drop M102 from the list or substitute NGC5866.:D