Astro 11
Lab 8

• This lab will teach you how three properties of a light source, absolute brightness, apparent brightness, and distance to the source, are related.


• You'll need your calculator for this lab, so be sure to bring it.


• Make sure your light meter is callibrated correctly. To check this, completely cover the detector surface with the meter on. The meter should read zero. If it doesn't, make sure to add the correction to every measurement. For example, if the meter reads -3 with the detector covered, you will have to add 3 to every measurement.


• When taking measurements with the light meter, make sure the detector is at exactly the same level as the light source.


• When taking measurements close to the light source, you may have to change the sensitivity to 10x in order to get a correct reading. When the light meter is saturated, it will usually read '1'. When this happens, move the sensitivity setting up one.


• Sometimes, you will notice that the reading on the light meter is constantly changing up and down. If this happens, go with the value that seems to be in the middle of the range of fluctuation.


• For part k, you will need the parallax formula from Lab 6.


• The important concepts in this lab should be quite obvious. Don't forget to mention your procedure for figuring out the relationship between luminostiy, flux, and distance.