With the holiday season upon us, there will be a rush to the department stores for cheap telescopes. Resist the urge. Read the article in the December issue of Sky and Telescope about selecting a first telescope. I have had many phone calls from people who have given up in frustration trying to use these wobbly, poorly constructed telescopes. Better to save up for a real telescope and enjoy it for a lifetime.
Astronomers express the brightness of celestial objects in terms of units called magnitudes.
Each one-magnitude difference corresponds to a factor of about 2.5 in brightness.