Name: ________________________ DUE 9/08 ID number: ________________________

Homework 2. Observing Mars

This chart shows Mars ( ) as it appears at the end of August, about one hour after sunset. The view is roughly South by South-West, the horizon is at the bottom, and the field of view is 60° across.

To locate Mars, stand with the point where the Sun set on your right. Look about 30° to the right and about 30° up from the horizon. You should see `Maui's Fishhook', which also forms the tail of the constellation Scorpius. Near the right-hand end of the hook is a bright star with a slightly reddish color; this is Antares, called the `rival of Mars'.

Mars itself is a bit to the right of Antares. It looks very much like Antares, but it's slightly brighter and does not twinkle much. Together, Mars and Antares are brighter than anything else in that part of the sky, so they should be pretty easy to find. To help you out, we will hold `Mars viewing' sessions on the lawn at the corner of University and Dole from 7:45 to 8:15 PM on 8/31 and 9/1 (weather permitting).

Your assignment is to observe Mars on at least two or three different nights and draw a chart showing how its position changes with respect to the stars. Concentrate on the brighter stars in the diagram on the right, which shows Antares, Mars, and other stars in Scorpius. When you make your first observation, draw Mars and the brighter stars in the head of Scorpius in the space below. Wait a few nights to give Mars a chance to move, and plot its new position on the chart. Finally, wait a few more nights, and again plot its position. Important: note the date and time of each observation. Try to make your chart as neat and accurate as possible. If you can, make an observation on the night before this assignment is due.

Joshua E. Barnes (
Last modified: August 29, 1999