Comparing Magnitudes (Measuring Brightness)

Submitted by Dane Toler, HOU Teacher and TRA

 

Here's an extension of SA14 for comparing magnitudes of the stars in M37. My teachers liked the group component of this and they built spreedsheats to calculate the magnitudes of the stars. They felt that this was a good integration of technology for students.

COMPARING THE MAGNITUDES OF STARS

A MODIFICATION FOR GROUPS

Work in groups of 4.

In Supplementary Activity (SA) 14 of the Brightness module answer questions 1 and 2 as directed, then open the image Mgclust on each machine. Working with your partners, use the ZOOM BOX to partition the image into four quadrants. Each student should select at least 6 stars in their segment and determine the magnitude of the stars. (Everyone must measure the brightness in counts of the brightest star in the cluster to calculate the magnitudes of the stars in their segment.) Record the coordinates, brightness counts, and magnitudes of the stars you chose neatly below.

HINT: When using the auto aperture function, make sure the circle does not overlap other stars nearby.

After you have measured and recorded the magnitudes of the stars in your segment, combine your results with the rest of your group to answer the questions below.

1. What range of magnitudes did you find for the cluster?

2. What are the magnitude and coordinates of the second brightest star that you found in the cluster?

3. What are the magnitude and coordinates of the faintest star the group found?

4. What is the average magnitude of the stars in the cluster?

5. If all the light from your stars were lumped together into one single star, how bright would it be?

6. Were all the stars you measured stars in the cluster? Explain your answer.

 

 

Lawrence Hall of Science | © 2012 | Updated June 20, 2011