Solar System (FoS)

In our look at the solar system this month, you find out what’s to see on the visible surface of the Sun using white light and hydrogen alpha solar filters. And you get a quick look at the basics of solar and lunar eclipses.
Click here to download notes for 'Observing the Sun' (PDF, 1 MB)
Click here to download audio for 'Observing the Sun' (MP3, ...

In our look at the solar system this month, we examine comets, perhaps the most unpredictable and visually striking objects in the night sky and one of the most fun to observe. It's always hard to tell when a reasonably bright comet will make an appearance, but when it does, you want to be prepared. This section will get you ready for the next 'Gre...

The waxing crescent Moon, Venus (middle), and Mercury in the twilight evening sky.
We continue our tour of the major planets of our solar system with a look at the so-called “inferior” planets Mercury and Venus, the planets closer to the Sun than Earth. When sufficiently separated from the Sun, these planets are visible without optical aid, and the...

(Note - There are no downloadable notes or audio for this lesson. There are links and information below to get you started finding the 'Lunar 100').
A map showing the position of each object in the Lunar 100 (image credit: Sky and Telescope)
This month, you look at the “Lunar 100”, a list of 100 interesting objects to see on the visible surface of ...

Beyond Saturn, in the icy reaches of the outer solar system, orbit the giant planets Uranus and Neptune. Uranus is the 3rd-largest planet by radius and the 4th largest by mass in the solar system, while Neptune is a little smaller but more massive than Uranus. Both planets were once considered gas giants like Jupiter and Saturn. Now astronomers und...