Images of asteroid 3 Juno taken in two different wavelengths of light with the 100-inch Hooker telescope at Mt. Wilson Observatory show what appears to be a 60-mile-wide crater at lower left in each photo. Material excavated by the collision that produced the crater “bite” shows very clearly at 934 nm. Sallie Baliunas et al.
When the word Juno shows up on this blog it’s usually in reference to the NASA spacecraft that swings around Jupiter every 53 days to take mind-blowing photos of the planet’s polar regions. Not this time. This time we’re going to find the asteroid 3 Juno which just happens to be making a close approach of Earth in the evening sky this month.
The “3” in front of Juno indicates the order of its discovery. Juno was first spotted by a German astronomer in 1804, the third small body found between Mars and Jupiter after 1 Ceres and 2 Pallas. It’s the 11th largest asteroid at 146 miles (233 km) across and has an elongated elliptical orbit around the sun, so Juno’s distance varies during its orbital period of 4.4 years from 186 million miles (300 million km) to 312 million miles (502 million km).