Pete,

Let's keep things in order:

The U2000 first came out in 1987 in its 2-volume edition, with the pages bass-ackward in relation to each other. Everyone (including me) complained about that. But it was a milestone anyway, and I'll never get rid of mine.

The MSA came out in 1997. It had a completely different design: 3 volumes, each covering 8 degrees of RA; it was the first to print the charts side-by-side so each was a double-page chart; and it was the first to portray stars by continual gradation as opposed to binning.

The U2000 2nd ed. came out after that (I'm not sure of the year; my copy is out in the observatory). They wisely adopted the double-page format and star portrayal method initiated by the MSA. They also eliminated roughly 50,000 stars from the atlas, and dramatically increased the number of DSOs. Roger Sinnott's hand is seen in all of this, and he's done a wonderful job of standardizing symbology in various atlases.

The MSA does not have the number of DSOs the U2000 has; but that wasn't its primary purpose. It was produced from a *star* catalog, and it's titled the "Millinnium *Star* Atlas" (not DSO atlas). The DSOs are gravy. The DSO symbols used are the same as used by the U2000, and the SA2000 before that, and the Atlas Coeli before that, etc etc. Commonly accepted and recognized symbology.

In absolutely no way whatsoever is the MSA a copy of the U2000. If anything, the opposite is true. But both are fine atlases that deserve a place in every astronomer's library.