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1995-01-03
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Distant Suns v5.0
Rob Hays
News items indicate that this summer's celestial fireworks
on Jupiter have spurred sales of telescopes. Whether you are
still considering joining this fast-growing hobby, or you are an
advanced amateur astronomer, Distant Suns is a program you need
on your Amiga's hard drive.
Recently updated to version 5.0, Distant Suns from Virtual
Reality Laboratories, is an Amiga classic that just keeps getting
better. This latest version represents a complete re-write of the
program code, and is the smoothest, most feature packed version
yet.
If you have never heard of Distant Suns (DS), the premise is
disarmingly simple. Put dots of light on the monitor screen so
that it matches what you would see in the actual sky. The reality
is a program that has grown to require 4 megabytes of free hard
disk space, a minimum of 2 megabytes of memory, and Workbench
2.04 or higher.
Because the stars and planets will appear in different
places depending on where on Earth you are observing from, DS has
always included provisions for entering the longitude and
latitude of your location. DS5 enhances this with the addition of
a scrolling list of more than 100 major cities around the world.
If you don't know the longitude and latitude of your home,
choosing the nearest major city will be good enough for casual
observation. If you need more precise information, check with
your local library.
The date also determines what is visible, and while DS reads
the current date and time from your system, you certainly are not
limited to what is visible today. Any date between 4713 B.C. and
9999 A.D. is fair game for observations, with one caveat. The
further away you are from the present date, the less accurate
calculations of positions are likely to be. As a practical
matter this would have little consequence, even if you could
take your telescope into the far past or future.
Once you have chosen a date and time to view, you can
control the passage of time by making it stand still, move
forward or backward, or run in real-time. Further controls allow
you to have each screen update reflect any interval from one
minute to 100 years. Used with the look down feature, you can
watch the planets whiz around the sun from a vantage point above
the sun.
You can choose to view the sky from earth in either of two
modes. Planetarium mode provides a view unobstructed by the Earth
itself, or Local mode, which actually places a silhouette of
hills and on the screen for a more natural view. There are so
many options available that you could spend many hours just
exploring different ways to look at things. For example, the
left mouse button can be set to perform any of three different
actions when clicked. Center the view on the point where the
mouse was clicked, zoom into the point clicked, or identify the
point. The field of view presented on your monitor screen can
range from 180 degrees, to an ultra-narrow .01 degree.
Moving about the virtual sky can be accomplished in several
ways. You can use the mouse in centering mode, or you could
select a quickmove direction from a menu. Alternately, you may
choose an object by name from a scrolling list, enter a specific
location coordinate, or use the motion control arrows that are
part of the control panel. This is a small window that also
gives quick access to the field of view setting, and current time
and date settings. Also available, and new to 5.0, is a tool box
window. This gives instant access to 20 of the most frequently
used commands.
If you have the mouse set to identify, and click on an
anonymous point of light, a small data window will pop up. This
provides information ranging from astronomical data such as
position, magnitude, distance, the next rise and set times for
viewing, and folklore. If the object is one of several that
images are included for, this box also gives you the chance to
view those images. These are full screen 16 color images from
either NASA space probes or ground-based telescopes. Owners of
AGA machines get 256 color images.
Also new to 5.0 is the ability to render planetary bodies as
shaded spheres. A requester allows you to pick any of the nine
planets, the sun, or moon, then choose any of eight positions
relative to your object to view from. Combining this feature with
the built-in animation functions would allow you to produce your
own fly-by animated tour of the solar system. While the detail of
these renderings is limited to solid colors, it is more
interesting than simple points of light.
The backyard astronomer often wants a quick overview of what
will be visible that evening. While books and magazines can
provide this information, Distant Suns can do it quicker and more
informatively. Picking the What's up menu item provides a choice
of three different displays. A planet chart that shows the
relative positions of the planets currently visible from your
location, a Rise/set plot that is a bar-graph chart which shows
the planetary visibility over the next 24 hour period, as well as
sunrise and sunset times, and the current time, or the Summary
selection. This lists the solar system objects, with their
location information, and highlights the currently visible
objects. Also shown here is the current moon phase and upcoming
meteor showers. A Lunar Phase chart is also available to quickly
judge how much moonlight will be competing with the fainter
starlight.
The supplied databases contain more than 8000 stars, and 100
nebulae. VRLI has additional datasets available if you desire.
Best of all, you can update this information yourself, entering
orbital parameters for asteroids or comets as they are
discovered. You can even customize the data used for the ground
silhouette to more closely resemble your location.
The 128 page spiral-bound manual contains information
ranging from the history of astronomical observations to
technical details of the program. There is even a section about
buying a telescope. Scattered throughout are tutorials that
familiarize the user with the features of the program, while also
providing eye-opening lessons. For example, one of the tutorials
demonstrates an event in 1989, where an asteroid made one of the
closest known approaches to earth. On March 22, 1989 this
asteroid passed within 400,000 miles of earth, and because of its
direction of travel, no one knew of its approach until after it
had passed us.
Distant Suns 5.0 is supplied on 5 disks, which contain
versions of the program suitable for systems with or without math
co-processors. The Commodore Installer will evaluate your system
and install the correct version, as well as the support files and
images. The program is not copy protected. DS supports Arexx for
control of the program features externally with more than 40
different commands supported, and sample scripts are included.
Don't stare up at the sky any longer wondering which point
of light is a star and which is Jupiter. Distant Suns is ready
to start you on a lifetime of skyviewing enjoyment.
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