Don't Miss Jupiter at its Brightest for Year on August 19

Jupiter at opposition on night of August 19-20

By Bob Berman
August 17, 2021
Jupiter Planet

On the night of August 19–20, Jupiter will be at its very brightest and best for the year. The Giant Planet is at opposition to the Sun. See Bob Berman’s viewing tips and don’t miss this night show!

Date of Jupiter’s Opposition

Jupiter’s “opposition” happens when Earth travels right between the Sun and the planet Jupiter.  At this point, the Giant Planet appears opposite to the Sun.

This event happens approximately every 13 months. Therefore, Jupiter’s opposition comes about a month later each year. In 2021, Jupiter’s opposition happens on August 19. Next year (2022), opposition is September 26.

Timing of Jupiter’s Opposition

Specifically, on August 19, 2021, Jupiter’s opposition equates to 00:00 UTC—which is 8 p.m. ET, 7 p.m. CT, 6 p.m. MT, and 5 p.m. PT.

Jupiter’s nearest point to Earth is always near opposition; in 2021, it’s just 5 hours later (05:00 UTC on August 20). 

This combination results in a best-viewing time for us: Jupiter is at its best and brightest. 

Viewing Tips to Find Jupiter

  • Finding Jupiter should be easy. Look for the brightest object rising in the eastern skies after sunset. As dusk subsides into evening, Jupiter will climb higher in the night sky. The Giant Planet is always bright, but it’s dazzling and astonishingly conspicuous against the constellation Capricornus.
     
  • Planet Venus is also bright this weekend; however, you won’t confuse the two planets. Venus will be blazing low in the west–on the opposite side of the sky!  At dusk, Venus is also descending in the evening sky while Jupiter is ascending.   See the Planet Rise and Set times.
     
  • No one needs to miss this night show. Even the most inexpensive backyard telescope or steadily braced binoculars will inspire ooohs and ahhhs. Jupiter reveals more detail through amateur instruments than any other planet (60¥ magnification is ideal). If you are not equipped, contact an astronomy club or a university about getting a look through a lens.
     
  • If you are busy or Mother Nature fails to provide clear skies on these nights, don’t despair. The sky king is out most of the night and visible 2 to 3 months before and after opposition.

Did You Know? Jupiter Facts

  • Jupiter reigns over a miniature solar system of at least 79 moons, including huge and ever-changing Io, Europa, Ganymede, and Callisto (named the Galilean Satellites in Galileo’s honor).
     
  • Its rotation, which is faster than that of any other planet, creates streaks: dark areas (belts) indicate rising clouds and gases; light areas (zones) indicate where belts sink.
     
  • It spins fast at its equator and slowly at its poles; where the momentums clash, gaseous layers produce violent eddies, curlicues, swirls, white spots, and the famous Great Red Spot—a hurricane three times the size of Earth. (You can see this on nights when Earth’s air is steady.)

Jupiter by the Numbers

  • Diameter: 11 Earths
  • Mass (quantity of matter): 318 Earths
  • Volume: 1,312 Earths
  • Length of year: 11.86 Earth years
  • Length of day: 9 hours 56 minutes
  • Surface temperature: –234°F
  • Density: 1⁄4 of Earth’s
  • Gravity: 2.4 times stronger than on Earth (a
  • 100-lb. person would weigh 240 lbs. on Jupiter)
  • Magnetic force: 14 times stronger than Earth’s
  • Average distance from the Sun: More than 5 times Earth’s
  • Closest distance to Earth: 367 million miles
  • Brightness, on average: Magnitude –2.3
  • Natural satellites (moons): At least 79

Source: 

The Old Farmer's Almanac

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