Photograph by NASA
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Skywatchers with binoculars and telescopes can hunt down the planet Neptune with some help from the moon this week.

Photograph by NASA

This Week’s Night Sky: Distant Giants Pose With the Moon

Comet Catalina glides past a pretty galaxy as it continues its journey out of the solar system.

Io Dance.  Late night on Tuesday, January 12, Io and its shadow take a trip across the face of  the volcanic moon’s parent planet, Jupiter, with both being visible on the planet’s surface together for a little more than an hour.

At 10:50 p.m. EST, Io’s shadow begins its transit, leaving the planet at 1:05 a.m. The moon itself starts its glide across the gas giant at 11:54 p.m., leaving at 2:08 a.m.

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This simulation shows Jupiter’s moon Io and the shadow it casts on the gas giant’s cloud tops, an event visible through backyard telescopes on Tuesday night.

Neptune Companion.  After nightfall on Wednesday, January 13, telescope users can look for the waxing crescent moon pointing the way to Neptune, the most distant giant planet in the solar system.

Neptune will appear only 5 degrees from Earth’s companion—equal to the width of your middle three fingers held at arm’s length. Don’t be fooled with the objects’ closeness in our skies, though, since the moon is only 1.3 light-seconds away and light from Neptune takes an incredible 4 hours and 15 minutes to reach us here on Earth.

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Late Wednesday night, the crescent moon will point the way to elusive Neptune, visible to binocular and telescope viewers in the constellation Aquarius.

Dipper Flyby.  Late night on Thursday, Friday, and Saturday, comet Catalina (C/2013 US10) will pass the iconic Big Dipper star pattern and some deep sky treasures.

On Thursday night, the comet—shining between 6 and 7 magnitude—will be easy to track down using binoculars as it passes Alkaid, the bright, naked-eye star at the end of the Big Dipper’s handle. The two should be separated by about 1 degree, making them both easily fit into the same field of view in binoculars or telescopes using low power.

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After darkness falls on Friday, look for the moon as it pairs up with the green giant Uranus in the constellation Pisces.

Then on Friday and Saturday, Catalina will pose next to the Pinwheel galaxy, also known as Messier 101. This giant face-on spiral galaxy, shines at magnitude 7.9. However, because of its low surface brightness, small telescopes will only reveal its central core, and a telescope with at least with a 15-centimeter (6-inch) mirror will be needed to glimpse its patchy spiral arms.

The comet is currently only 6 light-minutes away and the Pinwheel galaxy is 22 million light-years distant, but in the sky the objects will appear less than 3 degrees from each other—equal to 6 moon disks sitting side-by-side. This should make for a great photo opportunity to capture the pair together.

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This skychart shows comet Catalina parked between the Big Dipper star pattern and the Pinwheel galaxy, which will be visible through backyard telescopes.

Green Giant Followed. As darkness sets in on Friday, January 15, binocular and telescope users can easily hunt down the planet Uranus sitting perched above the moon. That night, the cosmic pair will only be separated by 5 degrees in the southwest sky.

Clear skies!

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