What is the difference in apparent flux of Venus and the Moon?
How much dimmer a star can be seen by the Hubble Space Telescope than can be
seen by the naked eye?
Two stars, A and B, have the same absolute magnitude. However, Star A has an apparent magnitude
of 7, while Star B has an apparent magnitude of 2. Which star is closer? By how much??
Star A and B have the same apparent magnitude. But we know that Star B has an absolute
magnitude of 7, and that this is 2 magnitudes larger than A, which has an absolute
magnitude of 5. Which star is Closer?
If I move a star to a distance twice as far away, how will that affect its:
A) Apparent Magnitude?
Each magnitude corresponds to a factor of 2.5 in
brightness. Referring to the chart on the previous page, can you answer these
questions?
-4 - (-11) = 7 magnitudes difference. Each magnitude is a factor of 2.5.
The difference in flux is 2.5 x 2.5 x 2.5 x 2.5 x 2.5 x 2.5 x 2.5 = 2.57 = 600.
2.524 = 3 x 109 (3 Billion times dimmer!)
The difference in magnitudes is 5. That represents a difference in flux of:
2.5 x 2.5 x 2.5 x 2.5 x 2.5 = 100. Star A is 100 times dimmer. Since the flux drops as
the inverse square of the distance, the difference in distance must be the Square Root
of 100. Star B is 10 times closer than Star A.
B) Absolute Magnitude?