Drops of Jupiter dominate the western skies this month

Sunday, July 2, 2017

This month finds Jupiter sliding into the western sky, making room for Saturn to dominate the night, while Mercury peaks above the western horizon.

July is the last good month to view the largest planet, Jupiter. Earth's orbit around the sun has carried Jupiter into the western sky, which is where you'll find it as darkness falls. Telescopic and binocular views are best when objects are at their highest.

Jupiter's radiance makes it easy to locate, though. Next month Jupiter is still visible, but will be low above the horizon. Planets and other objects in the sky are best viewed when highest up. Objects close to the horizon must shine through more atmosphere before reaching earth, and this diminishes the view.

One object that will never ascend to this prime viewing location is the planet Mercury.

The little planet's close proximity to the sun means Mercury is always hugging the horizon after sunset or before sunrise. On July 15, Mercury reaches its peak height in the western sky after sunset. Even at its peak Mercury is only a little ways above the horizon, so make sure you have an unobstructed view if you plan to look for the smallest planet.

The honor of being the highest planet this month, goes to Saturn. As darkness falls, Saturn is in the southern sky with its greatest altitude above the horizon. This month is the best time to view Saturn through a telescope along with its glorious rings, which reveal themselves even in a small telescope. Saturn is also backdropped by the splendor of the summer Milky Way. Its wispy clouds snake along the sky from the south to northeast. Help comes in locating Saturn on July 6 when the mostly full moon lies just above it to the left.

Brad Nuest is a space science educator at the Cosmosphere. Reach him at bradn@cosmo.org.