Homework 2. Observing Mars

Name: ________________________ DUE 9/18 ID number: ________________________

This assignment involves looking carefully at the sky and making some simple observations. To complete it successfully you will need to observe the planet Mars at least three times and chart its motion with respect to the stars. It's easier to notice the motion of Mars if your observations are made several days apart, so I suggest you begin your observations on the first clear night, make another observation about a week later, and try to make another observation just before the due date!

This picture shows the stars and planet Mars in the southern sky as they will appear at 8 PM on September 4. The horizon is at the bottom of the chart, with S (south) and SSW (south-south-west) compass points indicated. Mars is shown by the symbol near the center of this chart.

To find Mars in the sky, go out and look toward the south as twilight falls (around 7:00 PM). Mars will be visible as a bright point of light in the sky, long before it's dark enough to see stars. As it gets darker, you will see stars appear around Mars. Somewhat below Mars, look for `Maui's Fishhook', which is also the tail of the constellation Scorpius; to the left of Mars, look for `The Teapot', which is part of the constellation Sagittarius. To help you out, we will hold `Mars viewing' sessions on the grass in front of Hale Kuahine on East-West Road from 7:15 to 8:00 PM. The dates for these sessions will be determined in class.

Your assignment is to observe Mars on at least three different nights and draw a chart showing how its position changes with respect to the stars. Important: note the date and time of each observation. Concentrate on the position of Mars relative to the stars in the constellations of Sagittarius and Scorpius. When you make your first observation, draw Mars and the stars around it 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. 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. Which way is Mars moving?

Joshua E. Barnes (barnes@ifa.hawaii.edu)

Last modified: September 1, 2001