| The Disk of Mars is Usually Very Small and Detail is Hard to See in Most Amateur Telescopes | ||
Fig. 1. Drawing of Mars Through a Telescope (see box on right) |
But when Mars is near opposition and close to Earth, the disk becomes large enough for small telescopes to show several diverse features (Fig. 1 & 2). [Also see Mars Animations to see how Mars appears to change size as the distance between Earth and Mars changes.] Fig. 1 shows view at low magnification. Fig. 2 is enlarged to show possible observable features on Mars. (Higher magnification and filters might be required to see some of this detail). Also see the Astronomy Picture of the Day for 2003 August 19: "Mars Through a Small Telescope."
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The drawing below (Fig. 2) illustrates some of the Martian features you might try to see when you observe Mars (Fig. 1) in a small to moderate size, high quality telescope (as shown in Fig. 1). | |
Fig. 2. Mars Features Sometimes Visible Through Earthbound Telescopes |
Some features may not always show due to poor weather conditions at your observing sight (e.g., unsteady air and hazy skies). Other features show seasonal changes including the polar caps and albedo features. For example, poorly reflecting surface material (dark albedo features) often show seasonal changes (due to wind blown dust). Other features are transitory (polar ice comes and goes, clouds, fog and haze can change hourly.) In addition, large dust storms (some global) can hide part of all of the Martian surface. Finally, Mars also cycles through an incomplete cycle of phases (from full phase at conjunction or opposition to gibbous) so the disk may not always look round. Astronomers call the dividing line between the light (day) side and the dark (night) of a planet the terminator. (Can you see the terminator in the drawing?) |
Note: During the second half of 2003, you can watch the southern polar cap recede and develop rifts, dark spots, and a ragged border. (Summer begins in the Martian southern hemisphere 2003 September 29.) To learn more, see "Mars is Melting."
For more about observing Mars, get the Mars Observers Handbook from The Astronomical League and The Mars Observer's Tool Kit . Also get the following:
- Ephemeris for Physical Observations of Mars (2003) (for the technically minded)
- Mars Cartographic Maps (by Ralph Aeschliman)
- Martian Flare Watch
- Mars is Melting (watch the southern polar cap "melt" as summer approaches in the Martian southern hemisphere)
- Mars Map (from Alpo)
- Mars Nomenclature
- Mars's Dazzling Sky Show
- Mars Through a Small Telescope (from Astronomy Picture of the Day)
- Observing Form for Mars (from ALPO)
«Return to Mars Opposition Page»
(Page Last Updated August 23, 2003)
