Martian flights: explore the red planet from the comfort of your computer chair.
AS MUCH AS I HATE TO ADMIT IT, I will never travel to Mars or any other planet. Heck, I'll never even make it to the Moon. Most people in my situation would have to settle for seeing images on television or on a NASA Web site. For those of us who would really like to go to Mars but just can't swing it, Reading Information Technology Inc. (RITI) has a program that's the next-best thing to being there, and the experience is quite realistic.
Celestial Explorer: Mars is a heavyweight program designed to let the user explore the red planet's surface as though from a spacecraft in low orbit. The hardware requirements are somewhat hefty, which is not totally unreasonable, given the graphics-intensive nature of the program. RITI recommends a minimum of 16 megabytes of video memory (VRAM). I also suggest using the largest monitor possible to enhance the visual experience.
I initially had some problems installing Celestial Explorer: Mars on my office computer running Windows 2000. I contacted the manufacturer for technical support, and the response was extremely quick and helpful. I learned that the software requires administrative privileges to start, a consequence of the copy-protection scheme used to validate the CD-ROM upon launching. Despite the fix, the computer wasn't quite up for the task, so I installed the program on our machine at Lucile Miller Observatory. Under Windows XP Pro running on a 2.6-GHz processor with 64 MB of VRAM, I had no installation problems and performance was smooth.
The opening view of the red planet shows a region centered at the equator and 0[degrees] longitude, near Schiaparelli Crater. As I moved the mouse around, pop-up labels appeared when I crossed an overlaid line of longitude or latitude (or an intersection of both), as well as surface features and regions. A Navigator window lies at the lower left of the screen, which at first glance looks like a duplicate of the main MarsViewer window. This box shows you a global view of where on the planet the main window is centered, so you won't lose sight of the big picture as you explore the depths of Valles Marineris.
I tried my hand at moving around Mars without first consulting the documentation and found the user interface a bit unintuitive. I even had to look for the Help menu, which isn't in its standard place for Windows programs (the rightmost item in the menu bar). Very descriptive documentation comes in the form of a PDF file that can be accessed from within the program. I initially had some trouble roving around Mars's surface using the row of buttons just below the menu bar. The buttons with big yellow arrows pan the entire view seen in the main window. I had hoped that they would change the part of Mars seen in the window, but to do that I quickly found that I had to use the button with the arrow wrapped around a globe: the point-of-view changer. Clicking this button brings up the "POVmanager," and the user can then rotate Mars in longitude and latitude in adjustable increments (15[degrees] by default) or quickly change hemispheres. You can even use the mouse to retrieve the latitude and longitude of any surface feature and then center the target in the MarsViewer. Drawing these windows is the primary reason you need as much VRAM as you can get. Underequipped systems will update unacceptably slowly.
One very useful button brings up the Surveyor. From this dialog box you can use the mouse to select a starting point on Mars, click and drag to an ending point, and have the program tell you the coordinates of the two points, the distance between them (in both kilometers and miles), and the azimuth from the first point to the second. This tool is handy for planning potential rover excursions or perhaps for checking the geometry of clusters of craters. Other buttons allow you to zoom in (down to a resolution of about 10 km before it gets overly pixilated) and put a compass rose on the screen in case you forget which way north is.
Perhaps the most exciting feature of Celestial Explorer is the ability to show portions of Mars's surface in three dimensions. You can actually see the height of volcano Olympus Mons relative to the surrounding terrain. Clicking the 3D button brings up a smaller window, the 3D Viewer, with a perspective of the portion of Mars currently displayed in the main window.
Three-dimensional viewing works best when you're looking at a small section of Mars's surface. Displaying a full Martian hemisphere will cause a noticeable lag. Use the mouse to select a rectangular region, allow the main window to adjust to this zoomed view, and then use the 3D Viewer to see that portion in relief. At first I didn't think the 3D Viewer was working properly because it showed just an empty grid. I realized that I was looking straight down onto the surface. After I rotated the view by clicking on the appropriate buttons, the craters and other features stood out.
You can choose a wire-frame (for very fast rendering) or a realistic appearance (slower, but prettier), and you can even adjust the relief factor to exaggerate the topography. I really enjoyed the ability to explore the whole Martian surface in relief. You can literally scroll around the planet to observe the terrain, zoom in and out, and change orientation. This means you can basically create your own Martian flybys. All 3-D controls are available by button, menu, or a separate control panel in the 3D Viewer. For me, the 3-D flybys are the highlight of the program. Images of the main-window view can be saved as JPEG files for inclusion in documents or presentations. Of course, maps can also be printed.
As you might also expect, surface features can be labeled at will by toggling the appropriate buttons. The program has more than 1,400 names in its database. Let the mouse linger, and a landmark's name appears. If two or more features lie very close together--a crater within a crater, for example--all of them will be identified in the pop-up label. You can even add your own notes.
Celestial Explorer: Mars is a basic planetary atlas designed to take you to Mars and let you fly or hover above this alien world, but it won't let you actually land. You can't, for example, go soaring through Martian canyons. I wish it had a way to save the 3-D flybys as movies, but I saw no such feature. The amount of surface detail on Mars is stunning. I will never go to Mars, but with Celestial Explorer I can take a virtual flight any time I wish.
Celestial Explorer: Mars
RITI, 274 Main St., Suite 302, Reading, MA 01867; 781-942-1655; fax 781-942-2161; www.riti.com
Requirements: 500-MHz processor, Windows 98 or higher, OpenGL support, 128 megabytes RAM, 16 MB VRAM, 130 MB hard-disk space, and 1,024-by-768-pixel display
US price: $45
WHAT WE LIKE:
Very detailed graphics
Provides information on Mars missions and links to other resources (requires Internet access)
WHAT WE DON'T LIKE:
No way to save 3-D flybys as movies
Requires administrative privileges to run
Performance is very slow if you don't have enough VRAM
From Lucile Miller Observatory in Maiden, North Carolina, contributing editor JOE HEAFNER helps students and the public understand the sky.
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|Publication:||Sky & Telescope|
|Date:||Jun 1, 2004|
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