June 21, 2022: See the morning planet parade in the eastern sky before sunrise. The five-planet alignment is Mercury, Venus, Mars, Jupiter, and Saturn. How frequently are the five bright planets visible in their order from the sun after sundown?
by Jeffrey L. Hunt
Chicago, Illinois: Sunrise, 5:16 a.m. CDT; Sunset, 8:29 p.m. CDT. Check local sources for sunrise and sunset times for your location.
The sun reaches the celestial coordinates of the summer solstice at 4:14 a.m. CDT, signaling the sun’s farthest northern sunrise and sunset points, and the beginning of astronomical summer in the northern hemisphere. The sun’s arc across the sky is farthest north and longest of the year.
At 45 minutes before daybreak, the five bright planets and half-full morning moon are stretched across an arc from the east-northeast to nearly the south direction point.
The moon is over one-third of the way up in the sky above the southeastern horizon. Bright Jupiter is 4.6° to the upper left of the lunar orb.
Dimmer Mars is 13.6° to the lower left of Jupiter. At first the planet might be a challenge to see, but look carefully.
Saturn is slightly higher than the moon and nearly at the south cardinal point. It is over 40° from Jupiter.
Morning Star Venus, over 10° above the east-northeast horizon, is over 50° to the lower left of Jupiter. This brilliant planet may behind a neighborhood house, building or other obstruction. Find a clear horizon.
Mercury is 9.6° to the lower left of Venus.
Look for this unusual gathering of planets in their order from the sun. While five planets can appear in the sky simultaneously, they do not appear in order until the year 2100.
Visibility of the Five Planets, Evening
In yesterday’s article and associated podcast, the summary investigated the visibility of the five bright planets in order from the sun before sunrise. While five planets can appear in the sky before sunrise or after sunset, the planet order – Mercury to Saturn – appearance is rare.
In this article the evening sky is described.
In his book More Mathematical Astronomy Morsels, Jean Meeus lists twelve gatherings of five planets from 1980 through 2020.
With the current order of planets in the morning sky from Mercury to Saturn, how frequently does this occur in the evening sky? The planets line up from the sunset point with Mercury closest to the sun and Saturn at the eastern end – Venus, Mars, and Jupiter somewhere in between.
Meeus qualifies his list for observations at 40° north latitude and the planets are visible before sunrise or after sunset, where the sun is at least 5° below the horizon and Mercury and Saturn are at least 5° up in the sky. The important issue is that they are visible simultaneously after sunset.
Such groupings occur near the times of the Great Conjunctions of Jupiter and Saturn, occurring about every twenty years, across about a decade centered on the conjunctions. From 1985 to 1995, no parades occurred, the same for 2005 through 2015. Jupiter and Saturn were too far apart to be part of the simultaneous event.
So, planet parades of any combination occur about every other year for a span of ten years, centered on the Great Conjunctions, followed by decade-long periods of no displays of five planets simultaneously.
For evening parades for the planets in order, they occur before the Jupiter – Saturn conjunctions and after Saturn appears at opposition with the sun.
At opposition the sun sets as Saturn rises. Otherwise, Mercury sets before Saturn rises and simultaneous appearance is lost.
Secondly, Mars must be in between Venus and Jupiter. The event occurs before a Jupiter – Mars conjunction.
Thirdly, Venus and Mercury are past their superior conjunctions, meaning they are in the evening sky.
Looking at the Jupiter – Saturn conjunctions from 1961 to 2100, evening near-events occur. For example, during June 2040, the planets are in order, but Mercury sets only 13 minutes after sunset and is not visible. During September 2080, five planets are visible, but this is six months after the Great Conjunction, resulting in Jupiter and Saturn out of order. During March 2098, before the Saturn opposition, the five planets are in order, but Mercury sets before Saturn rises.
The result is that for the seven Great Conjunctions from 1961 to 2100, one Mercury, Venus, Mars, Jupiter, Saturn in order display occurs. That is, during early May 2100, the planets span 145°, from Mercury to Saturn. All the planets are visible and Venus is near the Pleiades star cluster. Jupiter is 6.6° west of Saturn. Their conjunction is September 24, 2100.
There it is – one simultaneous grouping of the five bright planets in order after sunset.
September 9, 2022: Mars continues its eastward march through the bright starfields of Taurus. The Harvest Moon is between Jupiter and Saturn after sunset.Keep reading
September 8, 2022: Three bright planets – Venus, Mars, and Jupiter – are visible before sunrise. Mars continues its eastward march in Taurus. After sundown, the bright moon is near Saturn.Keep reading
September 7, 2022: Mars passes Aldebaran, the brightest star in Taurus, this morning. The conjunction’s gap is 4.3°. This evening, the bright moon is near Saturn.Keep reading