At round 10:00 p.m. native time on Sunday (Nov. 9), when you look low towards the east-northeast sky, you will notice a waning gibbous moon, 72 p.c illuminated, and shining prominently beneath it will likely be a superb, silvery non-twinkling “star.” But in actuality, that star isn’t a star in any respect, however the largest planet in our photo voltaic system: the planet Jupiter. The distance between the moon and Jupiter shall be about 4.5 levels. Your clenched fist held at arm’s size is the same as roughly 10 levels. So, the hole separating this celestial pair will seem like equal to roughly half a fist.
Jupiter is at the moment located in opposition to the celebs of Gemini the Twins the place the ecliptic — the obvious path of the solar, moon and planets — comes farthest north, at +23 levels declination. This is lucky for Northern Hemisphere observers, because the farther north a planet is, the extra time it should spend above the horizon and the upper it should stand above the southern horizon on the midpoint of its path throughout the sky. For these dwelling within the southern U.S., when Jupiter crosses the meridian within the early morning hours, it isn’t removed from the purpose instantly overhead (the zenith).
When worlds (and a star) align
Because the moon appears to move to the east (left) against the background stars at roughly its own apparent diameter each hour, its position relative to Jupiter and Pollux will change noticeably during the course of the night.
The time when all three objects are more-or-less aligned along a straight line; when the moon appears to sit directly between Pollux and Jupiter, will differ depending on where you are located.
Those in the Eastern time zone will see this happen within a few minutes of 1:45 a.m.
For those living within the Central time zone, this will happen at around 12:25 a.m.
In the Mountain time zone the line-up comes at approximately 11:20 p.m. and for those in the Pacific time zone, only shortly after the moon, star and planet have risen: around 10 p.m., very low above the east-northeast horizon.
If you cast a gaze toward the moon as dawn breaks on Monday morning, note how much the configuration has changed; the moon has moved well off to the east leaving Jupiter and Pollux behind.
Telescopic treat
Jupiter is currently the best observer’s planet and will remain so all winter and into next spring. But sharp telescopic views are seldom possible until it is about 30 degrees above the horizon, given the typical turbulent state of Earth’s atmosphere. You’ll have to wait until midnight for Jupiter to reach 30 degrees altitude, which to some is the psychological dividing line between objects that are “low” and “well placed.” Half the area of the hemispherical sky dome is below 30 degrees altitude (or “three fists”).
If you do check out Jupiter with a small telescope on Sunday night, you’ll see all four Galilean moons, with Ganymede and Io on one facet of Jupiter and Europa and Callisto on the opposite. The ever-changing positions of the satellites relative to one another are at all times enjoyable to look at.
Joe Rao serves as an teacher and visitor lecturer at New York’s Hayden Planetarium. He writes about astronomy for Natural History magazine, Sky and Telescope and different publications.