Moon, Saturn, Jupiter in early November

At nightfall and early evening – November 1 and 2, 2019 – the waxing crescent moon shines in the vicinity of the planet Saturn, and the dazzling planet Jupiter sits below the moon and Saturn, fairly close to the horizon.

As the moon swings by Saturn in early November 2019, it’ll pass to the south of the ringed planet for most of the globe. However, for some far-southern latitudes, the moon will actually occult (cover over) Saturn on November 2, 2019. From New Zealand, this occultation of Saturn will take place at nightfall. (By the time that we in North America see the moon and Saturn at nightfall November 2, 2019, the moon will be well to the east of Saturn.)

We refer you to the worldwide map below via IOTA (International Occultation Timing Association), showing in which part of the world this occultation takes place. Only the part of the world between the solid white lines can see the occultation in a nighttime sky. The swath in between the dotted red lines depicts where the occultation happens in daytime; and the area in between the short blue lines shows where the occultation occurs at evening dusk.

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World map with elongated blue ovals over mid-Pacific and southeast of Africa.

Only a small section of the world between the solid white lines (New Zealand) gets to watch the occultation of Saturn at nightfall and early evening on November 2, 2019. Image via IOTA.

We give the occultation times for Auckland, New Zealand, in local New Zealand Daylight Time (NZDT):

Occultation begins (Saturn disappears behind dark side of moon): 9:17 p.m. NZDT
Occultation ends (Saturn reappears from behind moon’s lit side): 9:58 p.m NZDT

Visit IOTA if you wish to know the occultation times at other New Zealand localities, remembering to add 13 hours to change Universal Time (UTC) to local time (NZDT = UTC + 13 hours).

Saturn, the sixth planet outward from the sun, is the farthest and slowest-moving planet that we can easily see with the eye alone. Dazzling Jupiter, the fifth planet outward from the sun, is the second-slowest bright planet, after Saturn. For that reason, Jupiter/Saturn conjunctions are the rarest of bright planet conjunctions, by virtue of their slow motions in front of the constellations of the zodiac. Saturn takes nearly 30 years to go around the sun full circle whereas Jupiter takes nearly 12 years.

Antique etching of zodiac circle with triangles inside marked with year dates.

Johannes Kepler (1571-1630) maps out 10 heliocentric (sun-centered) Jupiter/Saturn conjunctions during the 180-year period from 1583 to 1763. After 60 years, the planets meet up at nearly the same place on the zodiac, with a displacement of about 8 degrees eastward relative to the background stars. Drawing taken from Kepler’s De Stella Nova (Prague, 1606).

The next grand conjunction will be forthcoming on December 21, 2020. From the years 2000 to 2100 inclusive, as viewed from our planet Earth, these Jupiter/Saturn conjunctions (in ecliptic longitude) happen on these dates:

May 28, 2000
December 21, 2020
October 31, 2040
April 7, 2060
March 15, 2080
September 18, 2100

These great Jupiter/Saturn conjunctions recur in periods of 20 years. Each year, Saturn completes about 12 degrees of its orbit around the sun, whereas Jupiter completes about 30 degrees. Therefore, in one year, Jupiter closes the gap between itself and Saturn by about 18 degrees (30 – 12 = 18 degrees). In a period of 20 years, then, Jupiter gains 360 degrees on Saturn (18 x 20 = 360 degrees), therefore lapping the ringed planet once every 20 years.

In early November 2019, let the moon be your guide to the planets Saturn and Jupiter. From New Zealand, watch the moon occult Saturn at nightfall/early evening on November 2, 2019. Next year, on the December 2020 solstice, the great conjunction of Jupiter/Saturn will happen for the first time since May 28, 2000.

Bottom line: See moon, Jupiter and Saturn in the early night sky, and watch for the occultation of Saturn from some Southern Hemisphere locations. Next year, watch for a Jupiter/Saturn conjunction.

Bruce McClure