Up till now, the planet that has been dominating our morning sky has been sensible Venus, which is seen low within the east-northeast sky starting actually on the morning time – about 90 minutes earlier than dawn.
This week the king of the planets rises round 9:45 p.m. native daylight time and — talking of the moon — late on Sunday (Aug. 14) for those who’re going through east quickly after 10:30 p.m., you may see a waning gibbous moon, three days previous full, standing a little bit over 5 levels to the proper of Jupiter.
Your clenched fist held at arm’s size measures roughly 10 levels in width, so on Sunday night time, simply over “half a fist” will separate Jupiter from the moon.
Jupiter and the moon will stay seen proper on by way of the remainder of the night time, peaking towards the south simply earlier than 4 a.m., at an altitude that measures greater than midway from the horizon to the purpose immediately overhead (the zenith).
Moreover, the orientation earlier than the 2 can have modified noticeably; as they cross the southern meridian at that early hour, Jupiter will look like glowing immediately above the moon. And they will even look like nearer to one another with the hole between the 2 having shrunk to three levels.
Opposition, when it will likely be nearest to Earth and within the sky all night time lengthy — from sundown to dawn — is just a bit over six weeks away, on Sep. twenty sixth. Also on Sunday, Saturn will arrive at its personal opposition. It’s positioned 46 levels to the west (proper) of Jupiter. Since your clenched fist held at arm’s size is roughly 10 levels in width, Saturn and Jupiter are at the moment about 4.5 “fists” aside.
Dance of the moons
And don’t neglect Jupiter’s four major moons, which had been found 412 years in the past by Galileo. They function a continuing delight to newbie astronomers and might be seen in any telescope and even binoculars. They orbit Jupiter so shortly (1.68 days for Io to 16.7 days for Callisto) that they modify their look from hour to hour and night time to nighttime.
As an instance, for those who prepare a telescope on Jupiter on Sunday night time, initially, you’ll see a single moon (Io) on one aspect of Jupiter and two (Ganymede and Callisto) on the opposite. But at 11:28 p.m. EDT (0328 GMT Monday, Aug. 15), the fourth moon (Europa) will emerge into view from behind the disk of Jupiter, becoming a member of Ganymede and Callisto.
Then on Monday at 2:15 a.m. EDT (0615 GMT), Io will fade away because it turns into eclipsed by Jupiter’s shadow. Shortly thereafter Io will cross behind Jupiter, however will emerge again into view a little bit over three hours later. Those within the central and western states, the place the sky will nonetheless be darkish, will then have the ability to see all 4 moons aligned on one aspect of Jupiter.
Size (and Distance) Matters
Finally, while you have a look at the moon and Jupiter late on Sunday night time, attempt to develop into conscious of the distinction in each their respective sizes and distances.
The moon, in fact, far outshines Jupiter by greater than 9 magnitudes; a brightness ratio of 4,370 to 1.
But the moon can also be a lot smaller than Jupiter. Indeed, the diameter of our pure satellite measures 2,158 miles (3,474 km) in comparison with Jupiter’s 88,846 miles (142,984 km) width.
What makes the moon loom a lot bigger and brighter is its distance. On Sunday night time the moon will likely be 232,300 miles (373,600 km) from Earth. But Jupiter will likely be 1,681 occasions extra distant: 390.6 million miles (628.5 million km) away.
And the truth that the moon is a lot nearer to us in comparison with Jupiter, means it strikes rather more quickly within the sky in comparison with the massive planet, at a price of roughly its personal obvious diameter per hour. So, that’s why once they ascend the predawn southern sky, the moon will seem noticeably nearer to Jupiter in comparison with once they had been rising within the east a number of hours earlier.
Joe Rao serves as an teacher and visitor lecturer at New York’s Hayden Planetarium (opens in new tab). He writes about astronomy for Natural History magazine (opens in new tab), the Farmers’ Almanac (opens in new tab) and different publications. Follow us on Twitter @Spacedotcom (opens in new tab) and on Facebook (opens in new tab).