Review: Star Clusters by Archinal and Hynes

For the last four or five years, I have looked in vain for the
book Star Clusters, by Brent A. Archinal and Steven J. Hynes.
In his famous book The Messier Objects, Stephen O'Meara cites
Star Clusters as the source for his data on open clusters,
listing it with a publication date of 1996.

I looked for Star Clusters in the on-line catalogs: no luck.
I looked for it in the library of the Smithsonian Astrophysical
Observatory, which happens to be around the corner from where
I live: no luck. Eventually it dawned on me that this book
had not been published yet, despite the citation in O'Meara.
But being an open-cluster enthusiast myself, and knowing the
reputations of Archinal and Hynes, and with the extra backing
of O'Meara, I was desperate to own this book. So when
Willman-Bell sent out a pre-publication offer, I jumped
at the chance to buy the book ASAP, and save some money
into the bargain.

The book arrived a couple of days after I phoned Willman-Bell,
well in advance of the promised July 30 delivery date.
Looking at it, it is immediately clear why this book took
seven years longer than originally planned. The scope of
the book is staggering. It aims to catalog every star cluster
in the Milky Way, both open and globular, including some that
have been observed only in infrared, plus everything that has
ever been listed as a star cluster but proved to be something
else or non-existent, including all asterisms known within
the amateur community. And if that isn't enough, it repeats
the same for both of the Magellanic Clouds, for M31, and for
the Fornax Dwarf Galaxy. Gack!

Every star-cluster enthusiast, amateur or professional, needs
to own this book -- there is no doubt about that. It is
comprehensive, authoritative, and full of useful information.
It is the fruit of an almost unimaginable scholarly effort,
cross-correlating all of the major sources on star clusters
back to the Herschels and before, and inspecting photographic
plates and the sky to resolve doubtful cases. It is, without
a doubt, the most accurate and comprehensive catalog of
clusters ever complied, resolving numerous conundrums of
missing or duplicate identity. The idea of listing all
false clusters and asterisms as well as true clusters is
brilliant and tremendously useful. First, as the authors
point out, it avoids having people re-identify the same
old pseudo-clusters over and over. Second, we amateurs
are quite fond of observing asterisms even when we know
quite well that they have no scientific significance.
The Coathanger is a case in point.

Having said that, the book is also deeply flawed, and leaves
me rather dissatisfied. I think that there are two basic
reasons for this.

First, despite those extra seven years, I suspect that the
authors ran out of time and energy, and exceeded the quota
of paper that Willman-Bell would allow. The book contains
useful extended notes on many clusters, especially ones
where the identity is in doubt, but also just ones that
happen to be interesting -- like M67 or Stock 1, to name
one well-known cluster and one that is less well known.
But why these and not, say, M44 and Stock 2, both of which
are equally interesting and unusual? For a very good reason,
namely that if there was a full discussion of each of the
listed Milky Way clusters (just over 2000 of them), the book
would weigh a ton and be utterly unreadable. And would have
overrun the deadline by seventy years, not seven.

Second, the book can't quite make up its mind what it is.
It is highly telling that nowhere is there a statement to
the effect "The purpose of this book is thus-and-such."

Is this book a catalog or a general discussion of clusters?
A little of both, but it is much more successful as a
catalog than it is as a general discussion. The explanatory
text on open clusters and globular clusters contains lots
of useful information, but it could be better organized
and better written.

Is this book for professionals or for amateurs? Clearly
both -- not for nothing is one of the authors a pro and
one an amateur. But if it is for pros, it should be more
technical, and if it is for amateurs, it should use less
jargon and be written more like a textbook and less like
a professional abstract. I suspect that everyone who
knows enough about clusters to read the text fluently
also knows in advance much of what it says. That was
certainly true for me.

Another thought is that the book might in some ways work
better as a machine-readable and machine-searchable
document than in it does in hardcopy. I have certainly
found that to be true for the work of the NGCIC project,
which heavily overlaps the work for this book. To look
up any object in this book by name, one needs first to
look in the appendix that lists all object aliases to find
its RA and its canonical name; then one can use the RA
to find the data listing in one or more separate catalogs
ordered by RA, and one can use the canonical name to see
if there are any extended notes, listed alphabetically
by canonical name. Usually, there are no extended notes.

Much of this hoopla seems inevitable given the fact that
most clusters have multiple aliases, although it would
be exceedingly handy if the index-by-alias indicated
whether extended notes exist, instead of requiring you
to discover that by trial and error. But somehow, the
whole process seems unsatisfactory in the modern age;
computers can do this kind of thing so easily!

The bottom line, I think, is that the audience for this
book is pretty clearly defined. All pros and amateurs
with a special interest in clusters *need* this book.
Whether we like it or not is not terribly relevant; the
information in it is far too important to pass up.

The average amateur very likely does *not* need or
want this book. The heart and essence of the book
is the work about the identities of doubtful clusters,
but most of the warhorse clusters have no identity
controversy, or if they do, it is amply discussed
elsewhere, e.g. in O'Meara. As for the explanatory
text about clusters, the average amateur would
probably be better served by one of the standard
college textbooks.

- Tony Flanders

I just received it last Friday, have only
had time to take a quick look, looks
great.