Anyone familiar with astronomy
software knows that free planetarium programs are a dime a dozen.
There’s Google Sky, Microsoft WorldWide Telescope, Cartes du
Ciel, and a host of others. This review focuses an oldie but a
Many folks have strong feelings and
attachments regarding their planetarium software and it often suits
their individual needs. For casual sky observers, Google Sky often
suffices. Observational astronomers like the sky chart feel of
Cartes du Ciel. Others who enjoy more serious armchair stargazing
enjoy Microsoft WorldWide Telescope for its versatility and ability
to dig ever deeper into a stellar object. And there are yet many
other programs available too.
Astrophotographers are another group
with their own requirements. They’re usually folks on a
mission. They know what they want to shoot and they know how they’re
going to get it. They wait patiently for good skies and when there’s
an opportunity, they pounce.
StarCalc isn’t like the other
free planetarium programs. It has no lofty goals. It displays no
spectacular photos of night sky objects. Its display is a very
simple rendering of the night sky as shown.
Memory and Configuration
Memory usage of StarCalc is very
small compared to other free planetarium programs. Compare for
example StarCalc with the following programs in terms of private
bytes memory usage:
Even more impressive, StarCalc’s
statistics above were running with numerous optional plug-ins
including a full Tycho-2 star catalog, SkyMap’s asteroids and
comets catalog, as well as the NGC 2000 catalog.
My field set up for astrophotography
is simple and my laptop is a brutally old eMachines running Windows
XP with only 458 megabytes. It doesn’t have an option for
upgrading the memory and has a tendency to overheat at normal
temperatures. StarCalc is a wonderful way to breathe new life into
StarCalc has an extensible interface
that allows users to add new modules as plugins. Plugins are varied
and include interfaces to the SAO Star Catalog, a compact StarCalc
version of the SAO star catalog, an interface to the Tycho-2 catalog,
an interface to the Guide Star Catalog, an interface to the USNO-A2
Star Catalog, SkyMap’s Asteroids and Comets database,
interfaces to calculate solar and lunar eclipses, an NGC 2000 catalog
plugin, a Milky Way overlay, and an ecliptic line overlay. I usually
run StarCalc with the Tycho-2 catalog and ecliptic line overlay.
Rendering is very fast, even on old hardware.
Configuration of StarCalc during the
first run or site relocation is relatively simple. Under the
Parameters->Options menu, it’s best to put in your current
It’s very straightforward and
there’s a nice helper button for converting GPS coordinates to
decimal format. And like Cartes du Ciel, StarCalc helps you improve
accuracy near the horizon by specifying ambient temperature and
pressure for your location.
When you load plugins such as the
Tycho-2 Star Catalog, you can control when the catalog is loaded
based on the zoom level as well as set a threshold for the magnitude
brightness display. This is handy when you’re doing final
navigations and framing for your astrophotography sessions.
Navigation in StarCalc is simple and
intuitive. Your mouse’s scroll wheel controls the zoom and
holding down the left mouse button allows you to pan the view as
desired. I’ve always been puzzled by Cartes du Ciel’s
decision to require one to hold down the scroll wheel in order to pan
Right clicking after selecting a
stellar object allows you to extract more information about the
object including type, ephemeris, rising and setting, and other data.
If you’re familiar with the description legend of Burnham’s
Celestial Handbook series, you’ll find that this program also
uses the same legend for detailed object descriptions.
Though StarCalc doesn’t
produce photography quality imagery of the sky, it’s still
possible to infer the general size of objects when you’re doing
imaging, particularly for objects that require low focal lengths.
When you zoom into objects, StarCalc
will draw a circle outlining the general size of a given object.
Highlighting an object and right
clicking allows you to obtain more information.
StarCalc also provides plenty of
copy/paste functionality for its data.
Solar System Objects
StarCalc provides good support for
solar system objects. For example, Jupiter’s position is
accurately displayed relative to the ecliptic and provides good data
on its satellites.
Zooming in on Jupiter provides a
simple display of where satellites are located relative to the time
Do you live in an area that provides
poor visibility when the ecliptic is low? You can easily set the
date to anytime in the future to see if your luck will improve.
StarCalc, like Cartes du Ciel and
Microsoft WorldWide Telescope allows you to connect your telescope as
a substitute for your GOTO hand controller.
Using free planetarium programs for
GOTO navigation can be very handy for astrophotographers because
you’re not beholden to a fixed set of bright stars listed in
the hand controller. You can align your scope to any object in the
StarCalc is fully ASCOM compliant.
Once you’ve installed your telescope control drivers, you
simply select Telescope->Choose option to select your particular
mount interface after ensuring that your mount is connected to the
correct port on your computer.
Slewing to an object in StarCalc is
as simple as right clicking on an object and selecting, “Slew
StarCalc is an older free
planetarium program that still works wonders in the field. The
beauty and elegance of StarCalc is in its simplicity. It simply
gives you a straightforward sky chart and keeps the user close and
involved with the basic motions of the night sky. It doesn’t
require any internet connection which makes it ideal for quick set
ups and configurations in remote locations. When you’re doing
astrophotography in a remote location, simplicity is your friend.
StarCalc’s last release was in
September 2003. Recently I spoke with the author of StarCalc and he
indicated that he was preparing to write another planetarium program.
It will be interesting to see what he comes up with.
StarCalc and its associated plugins
can be downloaded from:
There are also two mirrors located
at the following links: