Page20 January at 6:16pmPosts: 814 (0 today)Status: offline
See Jupiter and Moon Shine Dazzlingly Close Together Monday
Stargazers looking up as darkness falls on Monday (Jan. 21) will notice an eye catching pairing-off between two of the brightest objects in the nighttime sky, weather permitting.
The moon, appearing as a waxing gibbous phase, 78 percent illuminated, will appear to stand close below a very bright, non-twinkling, silvery "star." But it won't be a star that will be keeping the moon company on America's Inauguration Night, but the largest planet in our solar system: Jupiter.
Across much of the United States and southern Canada, this will be closest that the moon and Jupiter will appear relative to each other until the year 2026. On Monday night, the moon will be about of 248,700 miles (400,500 kilometers) from Earth, while Jupiter will be nearly 1,664 times farther out in space at a distance of 413.8 million miles (665.9 million km).
During Monday's stargazing event, observers have the chance to see what astronomers call an appulse — a very close approach of the moon to Jupiter. An appulse is a phenomenon caused by perspective only. There is no close physical approach in space between the two objects involved. Astronomers insist that appulses have no direct effect on the Earth.
The moon, moving around the Earth in an easterly direction at roughly its own diameter each hour, will creep slowly toward and ultimately pass just below the giant planet. Jupiter, meanwhile, will be shining about three times brighter than the brightest star, Sirius, offering a commanding sight for stargazers despite its close proximity to the moon. [Amazing Stargazing Photos for January]
Although it will be the moon that will be moving in Jupiter's general direction, the illusion will be that it is Jupiter that is moving, appearing to glide slowly along on a path taking it above the moon. A similar illusion occurs during a lunar eclipsewhen the dark shadow of Earth appears to be slowly creeping across the face of the moon. In reality it is the moon itself slowly creeping into the Earth's shadow.
After their closest approach Monday, the moon will spend the balance of the night moving slowly away to the left (east), leaving Jupiter behind.
The table accompanying this guide gives local times of Jupiter's closest approach to the moon's upper edge on the night of Jan. 21 for 20 major cities across the United States and Canada. Separation is given in terms of a fraction of an angular degree. The width of the moon is equal to one-half (0.50) of a degree