Sky and Telescope - August 2015 - 59

the big picture or the small, but not both together.
It was only when I arrived at my destination that I
started to appreciate the atlas properly. My usual observing style is to seek out a speciﬁc object and then poke
around and see what else is worth looking at in the vicinity. That's hard to do with most highly detailed atlases,
which show thickets of nearly identical symbols in any
crowded galaxy cluster or Milky Way ﬁeld. The diﬀerent
sized labels in the interstellarum atlas bring a crowded
ﬁeld to life, giving a sense of the character and diversity
of the individual objects. I could then start with the
most prominent ones and work as far down the visibility
classes as I liked.
In addition, the atlas marks double and multiple
stars with ticks whose length indicates the components'
separation, and each of the 2,950 double stars is labeled
with its name. I'm a huge double star fan, so this pleases
me greatly.
Of course, no atlas is perfect, and due to its huge
ambition and originality, the interstellarum atlas has
more ﬂaws than most. The biggest labels are delightfully
legible, but the smallest are pretty hard to read. That's
arguably appropriate when you're labeling a very faint
object. But I rely heavily on right ascension, declination,
and Greek Bayer letters for stars, and those are also in
minuscule type. And the atlas never uses leader lines to
connect symbols to their labels. That sometimes makes it
hard to puzzle out the correspondence in a crowded ﬁeld.
Although the atlas claims to be complete for 12-inch
scopes, it doesn't plot all the objects I've spotted with
my 12.5-inch scope. For instance, I found six galaxies

inside Messier 44 with my 12.5-inch when I was working
through the March 2009 Deep-Sky Wonders column.
The atlas only plots two - and they're not the ones that
I found easiest to see. Nonetheless, the atlas certainly
shows almost all objects of interest to me or most other
backyard astronomers.
The atlas is very strong on open clusters but possibly goes a little too far in this direction, showing some
large, obscure open-cluster candidates with no little or
no visual appeal. I would also prefer fewer asterisms and
fewer nicknames for deep-sky objects.
But to some extent this is quibbling. All star charts
require choices and compromises. The interstellarum
Deep Sky Atlas comes very close to maximizing the information that can be shown in a convenient, hand-holdable
atlas without compromising clarity. I ﬁnd that it adds
more to my observing sessions than any other printed
atlas I've used.
The atlas's biggest limitation is its scale and star
depth: they aren't really adequate to pin down the locations of its faintest objects. But that's where my planetarium app comes into its own. If I can't spot my target
immediately once I got down to the medium-power
eyepiece level, I bring out my tablet, with its inexhaustible supply of faint stars, to help me ﬁnish the job. I don't
see the atlas and app as competitors; instead I ﬁnd that
they complement each other perfectly - the atlas for the
big picture and app for the nitty-gritty details. ✦
Tony Flanders produced almost 1,000 star charts while he
was an associate editor at Sky & Telescope.

To Scale

The limiting magnitude of the atlas is 9.5. As is shown here with
Σ 666 in Auriga, double stars are marked with ticks, the length of
which indicates component separation. Each of the 2,950 double
stars included is labeled with its name. Also shown are 1,168
variable stars with a maximum magnitude brighter than 9.0.

Sk yandTelescope.com August 2015

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Sky and Telescope - August 2015

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