The Helix Nebula<\/a><\/strong><\/p>\nThe waxing gibbous Moon dominates the evening sky, located in Scorpius. You\u2019ll find it close to the Scorpion\u2019s red giant heart, 1st-magnitude Antares. Watch it close in as the hours tick by \u2014 our satellite will pass just 0.6\u00b0 south of this star at 1 A.M. EDT on the 21st, visible from the western half of the U.S.\u00a0<\/p>\n
An hour after sunset, the pair is roughly 20\u00b0 high in the south. Zoom in on the Moon with a telescope and seek out the large, flat-floored crater Plato, located in the lunar north, along the northern rim of Mare Imbrium (the Sea of Rains). The crater should stand out clearly as a dark spot along the rugged rim of Imbrium.\u00a0<\/p>\n
With the crater floor in your eyepiece, watch as the shadows streaking across it shorten as the Sun rises higher in the lunar sky. Over Plato, the terminator (the line dividing lunar night and day) is moving at nearly 6 mph (9.7 km\/h), and you can notice changes in the shadows here in just a few hours.\u00a0<\/p>\n
Although Plato\u2019s broad floor may appear flat and featureless at first, look closely \u2014 there are several smaller craterlets carving out material here, like someone took an ice cream scoop to the Moon\u2019s surface. These came after Plato\u2019s initial formation, which was more than 3 billion years ago.\u00a0<\/p>\n
Once you\u2019re through with Plato, take a moment to skim just a bit southeast along Imbrium\u2019s edge. Not far from Plato, there\u2019s a straight slash mark, this time like someone gouged out a piece of the mountainous terrain with a palette knife. This is called Vallis Alpes, or the Alpine Valley, and it cuts through (perhaps predictably) the Montes Alpes, or lunar Alps.\u00a0<\/p>\n
Sunrise:<\/strong> 6:16 A.M.
Sunset:<\/strong> 7:50 P.M.
Moonrise:<\/strong> 2:54 P.M.
Moonset:<\/strong> 11:50 P.M.
Moon Phase:<\/strong> Waxing gibbous (60%)
*Times for sunrise, sunset, moonrise, and moonset are given in local time from 40\u00b0 N 90\u00b0 W. The Moon\u2019s illumination is given at 10 P.M. local time from the same location.\u00a0<\/p>\nThe Moon passes 0.6\u00b0 south of Antares at 1 A.M. EDT on August 21, although it will have set before this for the eastern half of the U.S. Nonetheless, this part of the country will still see our satellite closely approaching the star before the pair sets.<\/p>\n
Once that happens, turn your gaze southeast to find Saturn already some 30\u00b0 high, shining so brightly it\u2019s easy to pick out among the dim stars populating this region. You\u2019ll want a telescope \u2014 even a small one will do \u2014 to view the planet\u2019s lovely ring system, which stretches some 43\u201d from end to end. That\u2019s more than twice the planet\u2019s apparent diameter, which is currently 19\u201d. The rings are showing off their southern side, and the southern pole of Saturn is visible as well.\u00a0<\/p>\n
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\t\tTitan is easy to spot near Saturn on August 21. Additionally, at 5 A.M. EDT, the 10th-magnitude moon Dione is preparing to just skim over the northern pole of the ringed planet. Observers in the western two-thirds of the U.S. will have the best views, as the sky will begin to grow light along the East Coast as Dione crosses north of Saturn. Only moons brighter than mid-10th magnitude are shown here. Credit: Stellarium\/Oleg Pluton<\/p>\n
Now look just northeast of the planet \u2014 you should be able to identify Titan, Saturn\u2019s largest moon, glowing at mid-8th magnitude less than an arcminute away. If you come back tomorrow morning, this moon will have slid westward in its orbit, standing northwest of Saturn the morning of the 22nd. It takes about 16 days in total for Titan to complete a full orbit.\u00a0<\/p>\n
If you have dark skies and a larger scope, you may also spot 10th-magnitude Rhea, Dione, and Tethys near Saturn as well. Around 2 A.M. EDT, all three are east of the planet, with Dione to the northeast (but closer in than Titan), Tethys to the east, and Rhea to the southeast. Over the next few hours, you can watch Dione moving west at a much faster pace than Titan \u2014 observers in the Central time zone and areas west of this will see Dione skim just north of Saturn\u2019s pole around 5 A.M. CDT.\u00a0<\/p>\n
Alison Klesman<\/strong>\u00a0is senior editor of\u00a0Astronomy\u00a0magazine. She holds a Ph.D. in astronomy and has studied a variety of topics, from minor planets to supermassive black holes.<\/p>\n","protected":false},"excerpt":{"rendered":"Back to Article List Set your sights on the Moon tonight to explore the crater Plato, as our…\n","protected":false},"author":2,"featured_media":646983,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_share_on_mastodon":"0"},"categories":[77],"tags":[18,19,17,2209,133,75779],"class_list":["post-646982","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-eire","tag-ie","tag-ireland","tag-observing","tag-science","tag-sky-tonight"],"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@ie\/117127110078266081","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/646982","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/comments?post=646982"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/646982\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/646983"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=646982"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=646982"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=646982"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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