The cream-colored inner planet and its ringed solar-system sibling will be at conjunction, or their closest apparent proximity to one another in the sky, tonight (Dec. 10) at 11:41 p.m. EST (0441 GMT on Dec. 11). The planets will appear low in the sky if you are looking southwest, no higher than 16 degrees above the horizon, according to In-the-Sky.org.
To spot Venus and Saturn , search for the constellation Sagittarius. You can also try finding it by first locating the stellar beacons Altair and Vega, which will shine overhead, according to a new video from NASA's Jet Propulsion Laboratory. The huddled pair of planets will be visible together through Dec. 13, according to the space agency.
Now, if you're trying to see Venus and Saturn, keep in mind that, while both planets will appear near to each other to the naked eye, they won't be close enough to both be seen in the viewfinder of a telescope, so for telescope users, some adjustment will be necessary!
During this event, Venus will be the brightest of the two with its magnitude of -4.0. Saturn will shine at a magnitude of 0.5.
The conjunction of Venus and Saturn doesn't mean they are physically near each other — there are three planets and a whole asteroid belt that separate the two worlds — they will just look like close neighbors, as they'll be sharing the same right ascension.
Just like with a map on Earth, the celestial sphere can also be broken up into a grid. Our planet is marked with a grid of longitude (east-west lines) and latitude (lines running north-south). Similarly, finding locations of interest in the sky is made easier through the imposition of a grid, which uses right ascension (left-right lines) and declination (top-down lines).
Right ascension is measured in units of time. So, when Venus and Saturn share the same right ascension, its value will be 19h 21m 10s. Declination is measured in degrees, arc-minutes (') and arc-seconds ("), starting at 0° at the celestial equator (the projection of the equator onto the night sky). The celestial North Pole would be +90° and the celestial South Pole would be -90°. Venus' declination tonight will be just 1°48' south of Saturn; the terrestrial planet will have a declination value of -23°51' during conjunction, and Saturn's declination will be -22°02'.
The Space.com staff has put together several telescope guides for the holiday season. Visit lists like "Best Telescopes for The Money" for recommendations on the perfect skygazing gift.(opens in new tab)