惑星の夕暮れと夜明け、月食、コマ星団

5月はどうですか？ 惑星の夕暮れと夜明け、月食、コマ星団。

星図マーキュリーは5月2日に西の空に低く現れ、三日月と明るい星アルデバランを伴います。 クレジット：NASA / JPL-Caltech

それは惑星を発見する2つの素晴らしい機会で始まりそして終わるかもしれません。 5月2日、日没から約45分後に西を見ると、地平線から約10度のところに、薄い三日月が付いた水星が見つかります。 月のすぐ南には真っ赤な巨星アルデバランがあり、これは水星とほぼ同じ明るさであるはずです。 （ちなみに、これは8月までの夕方に肉眼で惑星を見つける唯一のチャンスです。）

スカイチャートは、木星と火星が5月28日から30日の朝の空に非常に接近して表示される様子を示しています。 クレジット：NASA / JPL-Caltech

それから5月の最後の週に、あなたは毎朝として見ることができます[{” attribute=””>Jupiter and Mars get increasingly close in the predawn sky. Their morning meetup culminates in a close conjunction that you can watch on the 28th through the 30th, where they’ll be separated by barely the width of the full moon. Should look incredible with binoculars, where you can also see Jupiter’s largest moons.

Skywatchers in the Western Hemisphere can look forward to a total lunar eclipse in mid-May. The event will be visible across the Americas, Europe, and Africa – basically anywhere the Moon is above the horizon at the time.

Eclipse visibility map for the May 15-16, 2022 total lunar eclipse. Credit: NASA/JPL-Caltech

The visible part of the eclipse begins about 10:30 p.m. U.S. Eastern time on May 15th, with totality starting an hour later and lasting for about an hour and a half. Those in the Eastern U.S. will see the eclipse start with the Moon well above the horizon. For the Central U.S., the eclipse starts about an hour and a half after dark, with the Moon relatively low in the sky. On the West coast of the U.S., the Moon rises with totality beginning or already underway, so you’ll want to find a clear view toward the southeast if viewing from there.

Now, lunar eclipses are the ones that are safe to look at directly with your eyes, binoculars, or a telescope (unlike solar eclipses).

The Moon takes on a dim, reddish hue during the period of totality. Even though the Moon is fully immersed in Earth’s shadow at that time, red wavelengths of sunlight filter through Earth’s atmosphere and fall onto the Moon’s surface. One way to think of this is that a total lunar eclipse shows us a projection of all the sunrises and sunsets happening on the planet at that moment.

So check your local details for this eclipse, and find lots more eclipse info from NASA at this link. 

Finally in May, a really nice target for binoculars: the Coma star cluster. This loose, open star cluster displays 40 or 50 stars spread over a region of sky about three finger-widths wide. The brightest stars in the cluster form a distinctive Y shape, as seen here.

Sky chart showing where to find the Coma star cluster in May. The cluster is about 6° wide, and is located about 15° east of the hindquarters of Leo, the lion constellation, which is found high overhead in the south. Credit: NASA/JPL-Caltech

The Coma star cluster is located about 300 light-years away, making it the second-closest open cluster to Earth after the Hyades cluster in Taurus.

To find the Coma star cluster, look southward for the constellation Leo. It can be easiest to start from the Big Dipper, toward the north, and use the two “pointer stars” on the end which always point you toward Leo. Once you’ve identified Leo, the Coma star cluster is about 15 degrees to the east of the triangle of stars representing the lion’s hindquarters. It’s relatively easy to find with binoculars, even under light-polluted urban skies – as long as it’s clear out.

So here’s wishing you clear skies for finding the Coma star cluster and any other wonders you discover in the night sky in May.