Viewing Mars

In Fall 2005, Mars will come nearly as close to Earth as it did two years ago; in some ways, this passage will provide better views than the last one. However, given the rather poor image quality available to us in Kapiolani Park, we do not expect to be able to resolve surface details. We give some information just in case a miracle happens and we can enjoy a few seconds of excellent "seeing". Be assured, anyway, that by looking into the website "Solar system simulator" (see below) you can inspect an image of Mars far better than what can be seen using any ground-based telescope on our planet.

The table below provides simulated images and other data for Mars every Thursday from late October through the end of the semester. Each date links to an image showing how Mars will look at 21:30 HT (9:30 pm). The diameter column gives the angular diameter of the planet. The longitude column indicates what part of Mars will be facing the Earth. The final column lists some surface features which may be visible.

Mars rotates on its axis once every 24 hours and 37 minutes, so in one week it makes 6.82 rotations. Thus, if we observe Mars every week at the same time, we will see a somewhat different part of Mars each week; the surface features which are facing directly toward the Earth one week will appear toward the edge of the planet's disk the next week. By observing Mars every week for five weeks or more, we will get a chance to see every part of the Martian globe.

A conditioning factor is the weather, both here and on Mars itself. Dust storms occasionally occur on Mars; in extreme cases, they can obscure the entire surface of the planet for weeks on end.

Date Diameter
Visible Features
10/27/05 20.1 349 Sinus Meridiani, Sinus Sabaeus
11/03/05 20.1 287 Syrtis Major, Hellas
11/10/05 19.6 225 Mare Cimmerium
11/17/05 18.8 164 Mare Sirenum
11/24/05 17.8 101 M. Sirenum, Solius Lacus
12/01/05 16.7 38 Mare Erythraeum, Mare Acidalium
12/08/05 15.5 335 Sinus Meridiani, Sinus Sabaeus

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Roberto H. Méndez (
Last modified: October 24, 2005
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