Category: Feature

Astronomy, Feature, Sky Watching

2019-2020: Mars Until it Retrogrades
Mars (NASA Photo)

 

This chart shows the rising time differences for the rising times of the bright planets and stars near the ecliptic and sunrise for up to five hours before sunrise. The moon’s time differences are displayed in circles. The setting times of Jupiter and Saturn are graphed compared to sunrise. (Data from the U.S. Naval Observatory)

(This article was first published in the Northern Lights Fall Issue)

Mars begins an apparition that takes it to an opposition on October 12, 2020, 808 days following its 2018 perihelic opposition. The opposition, that will be highlighted in a future issue, brings Mars to its closest approach about a week before opposition. On October 6, the closest approach is 35.8 million miles, about 8% farther away than the preceding close passing. This corresponds to a smaller disk presented through a telescope.

The chart above, compiled with data from the U.S. Naval Observatory, shows the morning sky for 13 months beginning August 1, 2019, from Chicago, Illinois. Time intervals are noted on the chart and in the daily notes. Specific times are for Chicago, Illinois. To observe locally, refer to local sources for the times of sunrise and sunset; apply the time differentials in the notes.

The chart displays the time differences between the time of sunrise and the rising times for other planets, moon, and bright stars near the ecliptic, for up to five hours before sunrise. The moon’s rising time difference is displayed with circles. The setting time differences for Jupiter and Saturn, compared to sunrise, are displayed as well. The three phases of twilight are graphed compared to sunrise, and conjunctions are identified. The chart also notes several dates when the moon is near the bright planets.

Mars, Jupiter, and Saturn have oppositions that occur within 91 days in 2020. The interest in the Mars opposition adds a highlight to the Great Conjunction of Jupiter and Saturn that occurs late in the year. Such Jupiter – Saturn conjunctions occur about every 20 years.

The apparent sizes of Mars (in arcseconds) at its oppositions are graphed from 1930 to 2050. The larger apparent sizes occur when Mars is near perihelion and smallest when it is near aphelion. The time between oppositions for Mars, Jupiter, and Saturn are displayed for some oppositions (in days). The Great Conjunctions of Jupiter and Saturn that occur about every 20 years are displayed with yellow stars, including the time (in days) between oppositions of the two planets.

Mars’ apparent size at opposition (24.3”) is 8% smaller than the 2018 perihelic opposition and 11% smaller than the 2003 close opposition. This was described above with the close approach that is farther away in 2020 than the most recent perihelic opposition. The chart above displays the apparent size of Mars at its oppositions from 1930 through 2050. The twenty-year intervals of the Jupiter – Saturn Great Conjunction are displayed with yellow stars along with the time interval between their oppositions. For several Mars’ oppositions, the time intervals are noted for the Bright Outer Planets – Mars, Jupiter, and Saturn.

In this summary the events before opposition include monthly passages of the moon that highlight the beginning of a lunar occultation that is easier to view in the Western US, conjunctions with Jupiter, Pluto, Saturn, Ceres, and Neptune.

The apparition began with Mars’ conjunction with the sun on September 2, 2019. While dim, it began a slow crawl into the morning sky. By mid-month Mars was rising at Civil Twilight when the sun was 6° below the horizon.

At the beginning of October, the Red Planet (m = 1.8) is just above the eastern horizon, 45 minutes before sunrise, although it is a binocular object. The planet continues to rise earlier, Nautical Twilight (sun’s altitude = −12°) on October 6. Throughout October it rises earlier, rising at Astronomical Twilight on October 25. In the summary, each entry includes the planet’s magnitude, apparent size, distance from Earth in Astronomical Units, and difference between the planet’s rising time and sunrise, stated in minutes. This time changes in the summary on July 1, 2020, when the difference noted is between sunset and the rising of Mars. Here’s what to look for:

  • October 26: (1.8, 3.7”, 2.56 AU, 94m) Forty-five minutes before sunrise, the waning crescent moon (27.6 days old, 4% illuminated) is 5.6° to the upper left of Mars, about 8° up in the east-southeast. At this time, Mars is 4.5° below Gamma Virginis (γ Vir, m 3.4). Use a binocular.
  • November 10: (1.8, 3.8”, 2.50 AU, 122m) One hour before sunrise, Mars, about 9° up in the east-southeast, passes 2.8° to the upper left of Spica (α Vir, m = 1.0).
  • November 24: (1.7, 3.9”, 2.42 AU, 146m) One hour before sunrise, the waning crescent moon (27.3d, 6%) is 3.7° to the left of Mars, 15° up in the east-southeast. At the same time Mars is 9.5° to the upper right of Mercury (m = −0.4). Tomorrow morning, at the closest approach, the planets have about the same separation, although the gap is neither a conjunction nor a quasi-conjunction.
  • November 25: (1.7, 3.9”, 2.42 AU, 148m) One hour before sunrise, Mars is 14° up in the southeast, 9.5° to the upper right of bright Mercury (m = −0.3), 7° in altitude. The thin crescent moon (28.3d, 2%) is 5.5° to the lower left of Mercury. You’ll need a clear horizon to see the moon. It’s only 3° in altitude.
  • November 30: (1.7, 3.9”, 2.39 AU, 156m) One hour before sunrise, Mars, 15° in altitude in the southeast, is 0.2° to the lower left of Lambda Virginis (λ Vir, m = 2.8).

December 2019

As the year closes, Mars continues its eastward march. Early in the month, bright Mercury is to the lower left of Mars. Still over 2 Astronomical Units from Earth, Mars moves through Libra and between the pincers of the Scorpion. The planet rises about 3 hours before sunrise, but it’s low altitude and southerly location may send you on a chase to find a clear horizon.

  • December 1: (1.7, 3.9”, 2.38 AU, 157m) Mars moves into Libra, 7.3° to the upper right of Zubenelgenubi (α Lib, m = 2.8). Sixty minutes before sunrise, Mars is about 15° up in the southeast.
  • December 12: (1.7, 4.0”, 2.32 AU, 174m) One hour before sunrise, Mars, over 17° up in the southeast, passes 0.2° to the upper left of Zubenelgenubi.
  • December 18: (1.6, 4.1”, 2.28 AU, 181m) One hour before sunrise, Mars, nearly 18° up in the southeast, is 0.7° to the lower right of Nu Librae (ν Lib, m =5.2). Use a binocular to see the pair.
  • December 21: (1.6, 4.2”, 2.25 AU, 184m) One hour before sunrise, Mars, 18° up in the southeast, is 2.3° to the upper left of Iota Librae (ι Lib, m = 4.5).
  • December 22: (1.6, 4.2”, 2.25 AU, 185m) One hour before sunrise, Mars, 18° in altitude in the southeast, is over 8° to the lower left of the waning crescent moon (25.7d, 15%). The moon is above a line that connects Zubenelgenubi and Zubeneschamali (β Lib, m = 2.6). The lunar crescent is 3.5° to the upper left of Zubenelgenubi.
  • December 23: (1.6, 4.2”, 2.24 AU, 191m) One hour before sunrise, Mars, 18° up in the southeast, is 6° to the upper right of the crescent moon (26.8d, 8%).

January 2020

As the New Year breaks, Mars is an unimpressive “star” low in the southeast as sunrise approaches, rising about 4 a.m. CST. It continues to move through Libra and Scorpius and into southern Ophiuchus. At mid-month it passes north of its Rival, Antares.

Notice on the rising chart above that the time differential between the rising of Mars and sunrise decreases from late January through early-April. The declination of the sun is greater than Mars’ position.  The sun is moving toward the vernal equinox while Mars is approaching the ecliptic’s lowest point. The basic principle is that the farther north an object the earlier it rises. During January and February, the time interval between sunrise and Mars rising decreases nearly 20 minutes. This is reflected in the dip the Mars rising line takes on the chart. The differential increases after Mars moves farther north in declination.

  • January 7, 2020: (1.5, 4.4”, 2.14 AU, 196m) One hour before sunrise, Mars, 19° up in the southeast, is 1° to the right of Graffias (β Sco, m = 2.5). Mars enters Scorpius today and moves through in only 8 days.
  • January 8: (1.5, 4.4”, 2.13 AU, 197m) One hour before sunrise, Mars, over 18° up in the southeast, passes 0.7° below Graffias.
  • January 9: (1.5, 4.4”, 2.12 AU, 197m) One hour before sunrise, Mars, over 18° up in the southeast, is still near Graffias, passing 0.1° from Omega1 Scorpii (ω1 Sco, m = 3.9). Use a binocular to see the planet with the dimmer starfield.
  • January 15: (1.5, 4.5”, 2.08 AU, 198m) Mars moves into Ophiuchus. It crosses the constellation in 27 days. One hour before sunrise, Mars is over 18° in altitude in the southeast, 1.8° to the upper right of Omega Ophiuchi (ω Oph, m = 4.4).
  • January 18: (1.5, 4.6”, 2.05 AU, 199m) One hour before sunrise, Mars, over 18° up in the southeast, is 4.7° to the upper left of Antares (α Sco, m = 1.0). At the same time, Mars is 0.4° below Omega Ophiuchi. View the star and Mars in the growing twilight with a binocular.
  • January 20: (1.4, 4.6”, 2.04 AU, 198m) One hour before sunrise, Mars is 18° up in the southeast, 3.9° to the lower left of the crescent moon (25.2d, 19%).
  • January 21: (1.4, 4.6”, 2.03 AU, 199m) One hour before sunrise, Mars, 18° up in the southeast, is over 9° to the upper right of the moon (26.2d, 11%).
  • January 24: (1.4, 4.7”, 2.00 AU, 198m) Mars is 2.0 Astronomical Units from Earth. One hour before sunrise, the Red Planet is 18° up in the southeast, 6.3° to the upper left of Antares.

February 2020

During February, Mars moves from Ophiuchus into Sagittarius, through the rich galactic background of our galaxy’s nucleus region. Use a binocular to track the planet’s motion. After mid-month, the moon occults Mars in a bright sky as sunrise approaches. Mars heads toward conjunctions with Jupiter, Pluto, and Saturn next month. Watch the gaps close during February as the Bright Outer Planets appear above the southeast horizon before sunrise.

  • February 1: (1.4, 4.8”, 1.94 AU, 197m) Mars moves south of the ecliptic. One hour before sunrise, find it about 18° up in the southeast.
  • February 2: (1.3, 4.8”, 1.93 AU, 196m) One hour before sunrise, Mars, about 18° up in the southeast, is 1° above Omicron Ophiuchi (ο Oph, m = 5.1).
  • February 4: (1.3, 4.9”, 1.92 AU, 195m) One hour before sunrise, Mars is over 17° in altitude in the southeast. It is 1.8° to the upper left of Theta Ophiuchi (θ Oph, m = 3.2).
  • February 5: (1.3, 4.9”, 1.91 AU, 194m) One hour before sunrise, Mars, over 17° up in the southeast, is 0.9° to the upper left of 44 Ophiuchi (44 Oph, m = 4.2).
  • February 6: (1.3, 4.9”, 1.90 AU, 194m) Mars rises at its most southerly rising azimuth, 122°, until March 5, 2020.
  • February 7: (1.3, 5.0”, 1.90 AU, 194m) One hour before sunrise, Mars, about 17° in altitude in the southeast, is 0.6° to the upper left of 51 Ophiuchi (51 Oph, m = 4.8).
  • February 9: (1.3, 5.0”, 1.88 AU, 193m) Mars is about 20° to the upper left of Jupiter (m = −1.9), 7° up in the southeast, one hour before sunrise.
  • February 11: (1.3, 5.0”, 1.86 AU, 192m) Mars moves into Sagittarius. It begins to approach the bright nebulae and rich star field above the Teapot of Sagittarius. Use low powers to view the planet and the starry background. As the moon approaches the region during the next week, watch Mars move between the Lagoon Nebula (M8, NGC 6523) and the Trifid Nebula (M20, NGC 6514). Mars crosses the constellation in 50 days.
  • February 17: (1.2, 5.2”, 1.81 AU, 189m) One hour before sunrise, Mars, nearly 17° up in the southeast, is about 13° to the lower left of the moon (23.6d, 33%).
  • February 18: (1.2, 5.2”, 1.81 AU, 189m) One hour before sunrise, the crescent moon (24.6d, 24%), about 17° up in the southeast, is 0.4° to the right of Mars. As sunrise approaches, the moon inches toward the planet. If you can track Mars into a brighter sky, the moon occults it a few minutes after 6 a.m. CST, about 35 minutes before sunrise in Chicago. Observers in the Western U.S. see the moon occult Mars in a darker sky.
  • February 26: (1.1, 5.4”,1.74 AU, 185m) One hour before sunrise, Mars, 16° up in the southeast, passes 1.8° to the upper left of Kaus Borealis (λ Sgr, m =2.8), the star at the top of the lid of the Teapot of Sagittarius.
March 20: Mars passes 0.6° to the lower right of Jupiter. Locate the planets in the southeast about an hour before sunrise.

March 2020

Mars marches eastward in Sagittarius, above the Teapot’s handle, and continues to rise earlier. By month’s end, the planet rises before 4 a.m. CDT, as the clock advances one hour on March 8. The gaps to Jupiter, Pluto, and Saturn close as Mars passes the planetary trio this month.

  • March 1: (1.1, 5.5”, 1.70 AU, 183m) One hour before sunrise, Mars, 16° up in the southeast, is 10° to the upper right of Jupiter (m = −2.0).
  • March 5: (1.1, 5.6”, 1.67 AU, 180m) One hour before sunrise, Mars, 16° up in the southeast, passes 2.9° to the upper left of Nunki (σ Sgr, m = 2.0) and appears nearly 8° to the upper right of Jupiter.
  • March 11: (1.0, 5.8”, 1.62 AU, 178m) One hour before sunrise, Mars, 16° up in the southeast, is 4.9° to the upper right of Jupiter. Gaps until the Jupiter – Mars conjunction: Mar 12, 4.3°; Mar 13, 3.7°; Mar 14, 3.3°; Mar 15, 2.7°; Mar 16, 2.2°; Mar 17, 1.7°, Mars to the right of Jupiter; Mar 18, 1.2°; Mar 19, 0.9°.
  • March 15: (1.0, 5.9”, 1.59 AU, 177m) One hour before sunrise, Mars, 16° up in the southeast, is 10° to the upper right of Saturn (m = 0.7).
  • March 18: (0.9, 6.0”, 1.56 AU, 174m) The crescent moon (24.1d, 29%) joins the scene with Jupiter and Mars. The trio makes a small triangle, the moon is 2.4° to the lower right of Jupiter and 2.2° to the lower left of Mars.

 

  • March 20: (0.9, 6.0”, 1.55 AU, 174m) Jupiter – Mars conjunction! Mars is 0.6° to the lower right of Jupiter. The gaps after the conjunction as Mars moves away from Jupiter: Mar 21, 0.9°; Mar 22, 1.3°; Mar 23, 1.7°; Mar 24, 2.3°; Mar 25, 2.7°; Mar 26, 3.4°; Mar 27, 3.9°; Mar 28, 4.5°; Mar 29, 5.0°. The next Jupiter – Mars conjunction is May 29, 2022 in the morning sky. At that conjunction the sky has 4 bright planets – Venus, Jupiter, Mars, and Saturn – in the southeastern sky. The moon is nearby, a few days before the closest Jupiter – Mars passage. This morning the Mars – Saturn gap is 7.1°.
  • March 23: (0.9, 6.1”, 1.52 AU, 174m) Mars passes 0.1° to the lower left of Pluto (m = 14.3). At the beginning of morning twilight, Mars is about 12° up in the southeast. This is clearly a stretch to see this conjunction. A big scope and ideal sky conditions are needed to locate the distant world near Mars.
  • March 26: (0.8, 6.2”, 1.50 AU, 173m) Mars is nearly equidistant from the two bright giant planets, although Mars is below a line that connects Jupiter and Saturn. One hour before sunrise, Mars, 15° up in the southeast, is 3.3° to the lower left of Jupiter and 3.2° to the upper right of Saturn. The Jupiter – Saturn gap is 6.4°.
March 31: Mars passes 0.9° to the lower right of Saturn. The planets are in the southeast about an hour before sunrise.
  • March 31: (0.8, 6.4”, 1.46 AU, 172m) Mars – Saturn conjunction! One hour before sunrise, Mars, 16° up in the southeast is 0.9° to the lower right of Saturn. The Mars – Saturn gap grows after the conjunction: Apr 1, 1°; Apr 2, 1.4°; Apr 3, 1.9°; Apr 4, 2.5°; Apr 5, 3.1°; Apr 6, 3.7°; Apr 7, 4.3°; Apr 8, 5.0°. This morning gap to Jupiter is 6.1°. Mars moves into Capricornus.

April 2020

Mars is now moving away from Jupiter and Saturn and through the starfield of Capricornus. Continue to track it with low powers as it passes dimmer stars. It has a close appearance with the moon at mid-month. By month’s end the planet rises before 3 a.m. CDT.

  • April 5: (0.7, 6.6”, 1.42 AU, 172m) One hour before sunrise, Mars, nearly 16° up in the southeast, is 5.1° to the lower right of Beta Capricorni (m = 3.0). Look for Saturn and Jupiter nearby.
  • April 7: (0.7, 6.7”, 1.41 AU, 172m). One hour before sunrise, Mars is 10° to the lower left of Jupiter and over 4° to the lower left of Saturn.
  • April 15: (0.6, 7.0”, 1.34 AU, 173m) One hour before sunrise, Mars, 16° up in the southeast, is nearly 10° to the left of the thick crescent moon (22.0d, 45%). At the same time, the moon is 3.3° below Saturn. This morning Jupiter is 5.5° to the upper right of Saturn and nearly 15° to the upper right of Mars.
  • April 16: (0.6, 7.0”, 1.34 AU, 173m) One hour before sunrise, Mars, over 16° up in the southeast, is 3.8° to the upper right of the crescent moon (23.0d, 36%). Mars is 10° to the lower left of Saturn.
  • April 20: (0.5, 7.2”, 1.30 AU, 174m) One hour before sunrise, Mars, nearly 17° up in the southeast, is 0.8° below Theta Capricorni (θ Cap, m = 4.0). In the brightening sky, use a binocular to see the star with Mars.
  • April 23: (0.5, 7.3”, 1.28 AU, 175m) One hour before sunrise, Mars, about 17° up in the southeast, is nearly 15° to the lower left of Saturn. Meanwhile, the Jupiter – Saturn gap is 5.1°.
  • April 25: (0.5, 7.4”, 1.27 AU, 177m) One hour before sunrise, Mars, over 17° up in the southeast, is 0.2° to the lower right of Iota Cap (ι Cap, m = 4.2). Optical assistance helps see Mars’ close proximity to the star.

May 2020

Mars moves from Capricornus into the dim star field of Aquarius early in the month, brightening about 45% as it nears 1.0 Astronomical Unit away. The planet is about 40 times brighter than the stars it passes during the month. Continue to use low power to track the planet on its eastward march. The moon passes at mid-month, although about a degree farther away than in April. The planet passes Ceres late in the month.  As April closes, Mars rises before 2 a.m.

  • May 1: (0.4, 7.7”, 1.22 AU, 180m) Ninety minutes before sunrise, Mars, 14° up in the southeast, 0.9° above Gamma Capricorni (γ Cap, m = 3.6).
  • May 4: (0.4, 7.8”, 1.20 AU, 183m) Mars is 1.0° to the upper left of Delta Capricorni (δ Cap, m = 2.8), 90 minutes before sunrise. The planet is over 14° up in the southeast.
  • May 9: (0.3, 8.0”, 1.16 AU, 187m) Mars moves into Aquarius. Ninety minutes before sunrise, locate it nearly 16° in altitude in the southeast. Mars crosses the constellation in 47 days.
  • May 11: (0.3, 8.1”, 1.14 AU, 188m) About 90 minutes before sunrise, Mars, about 16° up in the southeast, passes 0.3° to the upper right of Iota Aquarii. (ι Aqr, m = 4.2).
  • May 14: (0.2, 8.3”, 1.13 AU, 192m) About 90 minutes before sunrise, Mars, nearly 17° up in the southeast, is over 9° to the upper left of the slightly gibbous moon (21.3d, 52%).
  • May 15: (0.2, 8.3”, 1.12 AU, 193m) Mars is nearly 17° up in the southeast, ninety minutes before sunrise, 4.5° to the upper right of the moon (22.3d, 42%).
  • May 18: (0.2, 8.5”, 1.11 AU, 196m) One hour before sunrise, Jupiter is 27° up in the south. Saturn is 4.7° to the left of Jupiter. This is a quasi-conjunction. Saturn began retrograding May 11 and Jupiter May 18. This occurs over 7 months before the two planets’ Great Conjunction. At this time, Mars, 36° to the left of Jupiter, is 21° up in the southeast.
  • May 19: (0.2, 8.6”, 1.11 AU, 198m) Mars passes nearly 20° north of Fomalhaut (α PsA, m = 1.2). While not near the ecliptic, Fomalhaut is a bright beacon among the dimmer stars of this region. And its place helps note the passage of bright solar system objects. One hour before sunrise, Mars is 22° up in the southeast while the star is about 4° in altitude in the southeast.
  • May 21: (0.1, 8.7”, 1.08 AU, 201m) About 90 minutes before sunrise, Mars, over 18° up in the southeast, passes 0.8° to the lower right of Sigma Aquarii (σ Aqr, m =4.8).
  • May 24: (0.1, 8.8”, 1.06 AU, 205m) Ninety minutes before sunrise, Mars, over 19° up in the southeast, is 7° to the upper left of Ceres (1Ceres, m = 8.0), 1.2° to the lower right of Delta Aquarii (δ Aqr, m = 3.2).
  • May 25: (0.1, 8.9”, 1.05 AU, 207m) About 90 minutes before sunrise, Mars, over 19° up in the southeast, passes 3.5° above Tau Aquarii (τ Aqr, m = 4.0).
  • May 30: (0.0, 9.2”, 1.02 AU, 215m) Mars passes 1.9° to the lower right of Lambda Aquarii (λ Aqr, m = 3.7). Mars is over 20° up in the southeast, ninety minutes before sunrise.

June 2020

During the month, Earth moves within 1 Astronomical Unit of Mars, while the Red Planet’s brightness grows nearly 0.5 magnitude. The planet passes Neptune late in the month. As the month closes, Mars rises at about 12:30 p.m. CDT.

  • June 1: (0.0, 9.3”, 1.00 AU, 218m) Mars is 1 Astronomical Unit from Earth. Ninety minutes before sunrise the planet is 21° up in the southeast.
  • June 5: (−0.1, 9.6”, 0.98 AU, 225m) Mars is 90° west of the sun. Ninety minutes before sunrise, it is nearly 21° up in the southeast.
  • June 8: (−0.1, 9.8”, 0.96 AU, 232m) Ninety minutes before sunrise Mars is nearly 24° up in the southeast. With a binocular observe that it is 1.5° to the lower right of Phi Aquarii (φ Aqr, m = 4.2) and 0.3° to the upper left of Chi Aquarii (χ Aqr, m = 4.9).
  • June 13: (−0.2, 10.1”, 0.92 AU, 243m) Ninety minutes before sunrise, Mars, 26° up in the southeast, is 1.6° to the lower right of Neptune (m = 7.9) and 4.7° to the upper right of the moon (21.6d, 49%). Use higher powers to see Neptune’s 2.3”-diameter disk.
  • June 25: (−0.4, 11.0”, 0.85 AU, 276m) Mars moves into Pisces, below the six, fourth magnitude stars that make the western fish. Mars makes a partial passage through Pisces in 13 days, then it moves into Cetus. It is 0.2° to the upper right of 27 Piscium (27 Psc, m = 4.8). Ninety minutes before sunrise, Mars is 31° up in the southeast.

July 2020

The time differential in the notes changes to rising time after sunset. (On July 8, Mars rises in the east 221 minutes after sunset.) Earth begins to close in on Mars. Now brighter than all the stars, except Sirius from the Northern Hemisphere, Mars gleams from the southeast before morning twilight begins. It moves into Cetus for a short duration, still among dimmer stars. Continue to track it with a binocular, although larger scopes should start to bring in details visually. The morning sky has a planet parade of all the planets in the solar system. In addition to ruddy Mars, brilliant Venus joins, Jupiter and Saturn, although brilliant Venus shines from the eastern sky. Jupiter and Saturn pass opposition six days apart, then Mercury pops into the sky. This results in 5 naked eye planets in the sky at once. Additionally, the telescopic planets are there as well: Uranus, Neptune, and Pluto. (Historically, Pluto is a planet. Without too much description, we have many things in astronomy that are misnamed – like planetary nebula.)

  • July 8: (−0.6, 12.2”, 0.77 AU, 221m) Mars moves into Cetus. Mars moves across this corner of Cetus in 19 days, then back into Pisces. The constellations are not uniform in shape and size. The ecliptic is less than 1° from a corner of Cetus near coordinates Right Ascension, 0 hours, 26 minutes; Declination, 2°. Cetus also bounds Aries on the south, but Mars moves north of the ecliptic after opposition and it does not return to this constellation this apparition. Ninety minutes before sunrise (about 4 a.m. CDT in Chicago), it is 37° up in the southeast.
  • July 11: (−0.7, 12.4”, 0.75 AU, 215m) Two hours before sunrise, Mars, nearly 36° up in the southeast, is over 6° to the upper left of the moon (20.1d, 65%).
  • July 12: (−0.7, 12.5”, 0.74 AU, 212m) Mars rises before midnight CDT. Two hours before sunrise, Mars, 36° up in the southeast, is nearly 6° to the upper right of the moon (21.1d, 56%). At this time, brilliant Venus is nearly 6° up in the east-northeast, 0.9° to the upper left of Aldebaran (m = 0.8).
  • July 14: (−0.8, 12.7”, 0.74 AU, 209m) Jupiter (m = −2.8) is at opposition. One hour after sunset, Jupiter is 10° up in the southeast, nearly 7° to the upper right of Saturn. Later this night, at 1 a.m. CDT, July 15, Mars is 11° up in the east, 77° to the east of Jupiter, now 26° up in the south.
  • July 18: (−0.8, 13.1”, 0.71 AU, 200m) Mars is 105° west of the sun. Ninety minutes before sunrise, it is 42° up in the southeast.
  • July 19: (−0.8, 13.2”, 0.71 AU, 199m) Two hours before sunrise, Mars, nearly 40° up in the southeast, passes 2.2° to the upper left of 20 Ceti (20 Cet, m = 4.8). This morning and for the next week, look for the five naked eye planets simultaneously. Mercury rises higher in the eastern sky and brightens as Jupiter appears lower in the southwestern sky. This morning the thin crescent moon is part of the scene. Look for them 45 minutes before sunrise. The moon (28.1d, 2%) is about 5° up in the east-northeast. Dim Mercury (m = 0.8) is about 5° to the right of the moon at about the same altitude, only slightly higher in the sky. It’s a binocular object. Brilliant Venus (m = −4.4) is over 20° up in the east, 4.5° to the lower left of Aldebaran. By this time, Mars is over 45° up in the south-southeast. Saturn (m = 0.1) is 9° up in the southwest, 7° to the upper left of Jupiter that is just above the southwestern horizon. The five naked eye planets are in the sky simultaneously with the bonus of a thin crescent moon!
  • July 20: (−0.9, 13.4”, 0.70 AU, 197m) Saturn is at opposition. One hour after sunset, Saturn is 10° up in the southeast, about 7° to the lower left of Jupiter. As midnight approaches, Mars is about 3° up in the east, about 74° east of Saturn, now 26° up in the south-southeast.
  • July 24: (−0.9, 13.8”, 0.68 AU, 189m) Two hours before sunrise, Mars, nearly 42° up in the southeast, is 5.6° to the lower right of Delta Piscium (δ Psc, m = 4.4).
  • July 27: (−1.0, 14.1”, 0.66 AU, 184m) Mars moves back into Pisces. Two hours before sunrise, the planet is over 43° up in the southeast. Brilliant Venus is over 60° to the lower left of Mars.
  • July 31: (−1.1, 14.6”, 0.64 AU, 178m) Two hours before sunrise, Mars, 45° up in the southeast is 4.9° below Epsilon Piscium (ε Psc, m = 4.2).

August 2020

Mars, now back in the constellation Pisces, continues its eastward march, as its brightness grows. While Mars brightens, Venus dominates the morning sky. Mars passes perihelion on August 2.

  • August 2: (−1.1, 14.8”, 0.63 AU, 175m) Mars is at perihelion, 1.38 Astronomical Units from the sun. It is 45° from its position when it is at opposition, measured along its orbit. Mars rises before 10 p.m. CDT. As midnight approaches the plant is about 10° in altitude in the east.
  • August 9: (−1.3, 15.7”, 0.60 AU, 164m) Two hours before sunrise, Mars, nearly 50° up in the southeast, is 0.9° to the upper right of the moon (19.6d, 72%).
  • August 14: (−1.4, 16.4”, 0.58 AU, 155m) Two hours before sunrise, Mars, 52° up in the south-southeast, is 1.0° below Mu Piscium (μ Psc, m = 4.8).
  • August 23: (−1.6, 17.7”, 0.53 AU, 139m) Two hours before sunrise, Mars, over 50° up in the south, is 0.5° to the upper left of Nu Piscium (ν Psc, m = 4.4).

September 2020

Earth closes to within 0.5 Astronomical unit of Mars. The planet is now appearing above the eastern horizon before midnight. Mars slows and stops its eastward motion against the starry background.

  • September 2: (−1.8, 19.2”, 0.49 AU, 120m) Two hours before sunrise, Mars, 55° up in the south, is 3.6° to the upper right of Xi Piscium (ξ Psc, m = 4.6). In the evening, three hours after sunset (about 10:30 p.m. CDT in Chicago), Mars is 10° up in the east.
  • September 4: (−1.9, 19.5”, 0.48 AU, 117m) Mars is 135° west of the sun. Three hours after sunset, Mars is nearly 11° up in the east. The gibbous moon (17.0d, 92%) is over 12° to the upper right of the planet.
  • September 5: (−1.9, 19.6”, 0.48 AU, 115m) Two hours before sunrise, Mars, 54° up in the south-southwest, is 10° to the upper left of the moon (17.3d, 91%). In the evening, 3 hours after sunset, Mars – 11° up in the east – is 0.8° to the upper left of the moon (18.0d, 86%).
  • September 6: (−1.9, 19.8”, 0.47 AU, 112m) Two hours before sunrise, Mars, nearly 55° up in the south-southwest, is 2° to the lower right of the moon (18.3d, 85%). In the evening, three hours after sunset, Mars – 11° up in the east is nearly 12° to the upper right of the moon (19.0d, 79%).
  • September 8: (−2.0, 20.1”, 0.47 AU, 108m) Two hours before sunrise, Mars is 53° up in the south-southwest. This evening the planet rises before 9 p.m. CDT. Three hours after sunset, Mars is over 12° up in the east.
  • September 11: (−2.1, 20.4”, 0.46 AU, 101m) Mars eastward motion ends and it begins to retrograde. It is 141° west of the sun. Two hours before sunrise, the planet is 52° up in the south-southwest. In the evening, three hours after sunset, Mars is nearly 14° up in the east.

Until retrograde began, Mars passed four planets and a minor planet, and had an occultation with the moon. Earth is now closing in toward its closest approach and Mars’ opposition, about a month away. While not as close as the last perihelic opposition, the next opposition occurs farther north and promises great views. In a later issue, we pick up the story of Mars at opposition.

 

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Astronomy, Feature, Sky Watching

2019-2020: Venus as an Evening Star
August 4, 2018: Venus from the Arizona desert.

Link to our semi-technical analysis of this apparition.

Venus shines as a brilliant evening star during late 2019 and early 2020.  The apparition (appearance) includes conjunctions with Jupiter and Saturn that occur within a month.  Then Venus moves past Neptune and Uranus.  The appearance includes a close conjunction with the Pleiades and a quasi-conjunction (near conjunction) with Beta Tauri.  The apparition ends as Venus dives toward inferior conjunction and has a conjunction with Mercury, followed by a pretty grouping of the two planets, Beta Tauri, and the moon.

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The young lunar crescent’s appearance with Venus is always an exciting time to view and photograph the brilliant planet and the moon displaying Earthshine.  The best view occurs on November 28, when the pair is 1.9° apart.

Venus as an Evening Star. The chart shows the setting time of Venus and other celestial objects in the west compared to sunset.  Data from the U.S. Naval Observatory for Chicago, Illinois.

The chart above shows the setting time of Venus compared to sunset along with other bright stars near the ecliptic and the moon.  The chart is constructed from data from the U.S. Naval Observatory for Chicago, Illinois.   When the Venus line crosses the lines of other objects, they set at the same time.  A conjunction occurs near the intersection.  If a moon circle is near one of the setting lines, a conjunction may occur on that date, or on the day before or day after the date the moon and that object are plotted together.

It is important to note that because two objects set at the same time, they may not appear close together in the sky.  Two objects that are far apart in the sky can set at the same time.  Because objects have been selected for the chart that are near the ecliptic, close conjunctions might occur.  While Antares, Aldebaran, and Pollux generally lie near the ecliptic, the conjunctions with planets usually have gaps of several degrees.

Venus is at superior conjunction on August 14. 2019 when it is on the far side of the sun.

Venus passes superior conjunction at 1:07 a.m. CDT on August 14, 2019, nearly 1.3° north of the sun.  Because of the time, the conjunction is invisible in the Central U.S., but Venus can be found with optical assistance in a clear sky northeast of the sun after it rises that morning. Great care must be taken for visual observations of the planet in close proximity to the sun

Venus Emerges Into Bright Evening Twilight

Venus climbs into bright evening twilight in the southwestern sky and is soon visible in darker skies.  It is headed toward a conjunction with Jupiter in about a month.  On October 27, Venus is 20° from the sun and sets in the southwest and about an hour after sunset.

In the charts that follow, several of them are displayed for a time interval after sunset.  Use local sources for the time of your sunset.  The U.S. Naval Observatory has an online calculator that displays a year of sunrises and sunsets.  Enter your state and city into Form A on the website. Make appropriate changes for Daylight Saving Time.  For readers outside the U.S., enter your longitude and latitude in Form B for your yearly table.  Click here.

2019, October 29: Venus appears 4.7° to the lower right of the crescent moon. Jupiter is to the pair’s upper left. Find a clear horizon to locate Venus and the moon.

The moon makes its first appearance with Venus on October 29, as illustrated above.   Thirty minutes after sunset, the moon appears to the upper left of Venus, only 4° up in the southwest with bright Jupiter to the upper left of the pair. The moon is 1.8 days old, past its New phase, and 4.4% illuminated.  The moon appears with Jupiter two evenings later (October 31).  By early November, Venus continues to set later.  By November 4, it sets about an hour after sunset.

Venus – Jupiter Conjunction

For the second time during this apparition of Jupiter, Venus passes the Giant Planet.  Watch Venus move into Ophiuchus and then it passes Jupiter on the edge of Sagittarius. The next conjunction is February 11, 2021, but the planets rise during bright morning twilight.  On April 30, 2022, the planets rise into the eastern sky about 90 minutes before sunrise 29’ apart, an Epoch Conjunction.  During the current apparition, Venus and the moon have a very nice pairing (1.9°) near the end of November.  Follow the progress of the 2019 Venus – Jupiter conjunction during November:

On November 9, thirty minutes after sunset, Venus, nearly 6° up in the southwest, is 3.9° to the upper right of  the star Antares. The Venus – Jupiter gap is 15°. Venus continues to set later, appearing higher at the same time each evening.

2019, November 13: Venus is about 10° from Jupiter, 30 minutes after sunset.

By November 13, thirty minutes after sunset, the Venus – Jupiter gap is over 10°. Venus is 6° up in the southwest.  A few evenings later, November 16, Venus is 25° east of the sun. Thirty minutes after sunset, it is 7° in altitude in the southwest.

2019, November 19: Forty-five minutes after sunset. Brilliant Venus and Jupiter are 5° apart in the southwest.

Venus continues to close in on Jupiter.  By November 19, forty-five minutes after sunset, the Venus – Jupiter gap is about 5°. Venus is 4° up in the southwest. The separations until the conjunction: Nov 20, 3.9°; Nov 21, 2.8°; Nov 22, 2.1°; Nov 23, 1.5°, Venus is to the lower left of Jupiter.

2019, November 24: Venus-Jupiter conjunction. Look in the southwest about 30 minutes after sunset.

On November 24, Venus is closest to Jupiter! Forty-five minutes after sunset, Venus, nearly 7° up in the southwest, is 1.4° to the lower left of bright Jupiter. This evening, Venus sets at its southern-most azimuth, 236°. It sets here until December 1.  The Venus – Jupiter separations after conjunction: Nov 25, 2°, Venus is to the left of Jupiter; Nov 26, 2.8°; Nov 27, 3.7°, Venus is to the upper left of Jupiter; Nov 28, 4.7°.

On November 26, Venus sets at the end of twilight, over 90 minutes after sunset, when the sun is 18° below the horizon.  Venus sets after the end of evening twilight until May 19, 2020.

The next evening, November 27, thirty minutes after sunset look for the crescent moon (1.3d, 2%), about 5° up in the southwest. It is nearly 11° to the lower right of Venus, with Jupiter between them, but Jupiter is closer to Venus.

2019, November 28: Venus and the moon are very close, only 1.9° apart!. Jupiter is to the lower right of the Venus and Saturn is to the upper left.

On November 28, at mid-twilight (about 45 minutes after sunset) Venus and the moon (2.3d, 6.3%) have a classic appearance, with Venus 1.9° to the lower right of the moon. At this time, Venus is about 7° up in the southwest.  Both appear in the viewfinder of a camera with a 300 mm focal length lens.  A longer exposure reveals Earthshine on the moon.

2019, November 30: Venus passes Kaus Borealis, the star at the top of the lid of the Teapot of Sagittarius.

Venus continues to move away from Jupiter.  On November 30, Venus passes 0.8° to the upper right of Kaus Borealis, the star at the top of the lid of the Teapot of Sagittarius.

Venus – Saturn Conjunction

As Venus moves away from Jupiter, it approaches and passes Saturn. Watch Venus close the gap on Saturn and pass it on December 10. Venus passes Saturn again on February 6, 2021 in a difficult-to-see conjunction, just 5 days before the Venus-Jupiter conjunction of 2021.  On the morning of March 29, 2022, Venus is 2.1° from Saturn. Mars is nearby, 4.4° to the upper right of Saturn.

2019, December 2: Venus is about 10° to the lower right of Saturn.
  • The diagram above on December 2, 45 minutes after sunset, shows Venus about 9° up in the southwest. It is about 10° to the lower right of Saturn.  On the next evening, December 3, the three evening planets – Venus, Jupiter, and Saturn – are nearly equidistant tonight, but they are not along the same arc in the sky: Venus – Saturn, 8.6°; Venus – Jupiter, 9.7°.
2019, December 5, Venus passes the star Sigma Sagittarii. Venus is about midway between Jupiter and Saturn.

Venus continues to move eastward compared to the starry background toward Saturn.  On December 5,  Venus passes 1.9° to the upper right of Sigma Sagittarii.  Venus continues to close the gap on Saturn. Venus – Saturn separations until the conjunction: Dec 7, 4.3°, Dec 8, 3.3°; Dec 9, 2.4°.

2019: December 10: Venus passes Saturn.

Venus passes Saturn on December 10. At mid-twilight, Venus, over 11° up in the southwest, is 1.8° to the lower left of Saturn. Venus – Saturn gaps after the conjunction: Dec 11, 1.9°; Dec 12, 2.5°; Dec 13, 3.4°, Venus is to the upper left of Saturn; Dec 14, 4.4°, Dec 15, 5.4°. Venus continues eastward against the starry background, moving farther away from Saturn. on December 19, one hour after sunset, Venus, 12° up in the southwest, is nearly 10° to the upper left of Saturn. Venus moves into Capricornus.

2019, December 28: The crescent moon is 2.4° below brilliant Venus.

By the end of 2019, the crescent moon rejoins Venus.  One December 28, about an hour after sunset, Venus is about 15° up in the southwest. The moon (2.8d, 8%) is 2.4° below the planet.

Venus as an Evening Star in 2020

2020, January 15: Venus shines brightly in the western sky in early 2020.

Venus begins the New Year among the dimmer stars of eastern Capricornus.  Now setting abut 3 hours after the sun, watch Venus move eastward into Aquarius and toward a Neptune conjunction.

2020, January 27″ The moon appears near the star Phi Aquarii and the planet Neptune. A small telescope or binocular is needed to see Neptune that appears as a bluish “star.”

Venus continues moving eastward, appearing higher in the sky when it is completely dark.  By January 27, Venus is 40° east of the sun. At the end of evening twilight, Venus, 18° up in the west-southwest, is 0.2° to the upper left of Neptune, nearly 7° above the crescent moon (3.1d, 9%) and 0.2° to the lower right of Phi Aquarii.  A binocular or small telescope is needed to see Neptune.

On the next evening, January 28, at the end of evening twilight Venus, about 18° up in the west-southwest, is 7° below the moon (4.1d, 15%).

Venus Moves Into Pisces

During February brilliant Venus, still moving about 1.2° each day along the ecliptic, moves into Pisces and passes several dimmer stars.  The starry background is dim.

2020, February 26 & 27: The crescent moon appears near Venus.

By the end of February, the crescent moon is back in the evening sky.  On February 26, at the end of twilight, the moon (3.4d, 10%), 14° up in the west, is 10° to the lower left of Venus. On the next evening, February 27, at the end of evening twilight, Venus, 25° up in the west, is nearly 7° to the right of the waxing crescent moon (4.4d, 16%)

Venus Moves Through Aries: A Venus – Uranus Conjunction

During March, Venus crosses into Aries, passing far from the constellation’s brighter stars.  It is heading toward a conjunction with Uranus

2020, March 7: Venus passes Uranus. Use a binocular to locate the dimmer planet.

Venus closes in on the planet Uranus.  On March 7, Venus is 2.2° to the right of Uranus.  The planet is brighter than Neptune, which Venus passed in January.  In a dark sky, Uranus is visible in a dark sky to those with good eyesight.  Use a binocular to see it easier.

2020, March 24: Venus reaches its greatest separation from the sun as seen from Earth.

Venus continues to set later in the evening and appears farther from the sun.  On March 24, Venus is at greatest elongation (46.1°) at 5:13 p.m. CDT. We see Venus farthest from the sun during these evenings. At the end of evening twilight, Venus is over 25° up in the west.

2020, March 27 & 28: Venus closes in on the Pleiades as the moon passes by the brilliant planet.

As the weather warms in the northern hemisphere, Venus approaches the Pleiades star cluster.  Here we reference the Pleiades with its brightest star Alcyone (Eta Tauri)  The moon enters the region with Venus.  On March 27, Venus is nearly 10° to the upper right of the waxing crescent moon (3.7d, 12%) and 6.5° to the lower right of the Pleiades. Here are the gaps as Venus closes in on the star cluster: March 30, 3.6°; March 31, 2.7°; April 1, 1.8°; April 2, 0.9°, Venus is below Alcyone.

On March 28, at the end of evening twilight, Venus, 26° up in the west, is 8° to the lower right of the moon (4.7d, 18%) and 5.5° to the lower right of the Pleiades. The trio – Venus, Moon, and Pleiades – makes nearly an equilateral triangle. Venus sets at its maximum interval after sunset – 4 hours, 7 minutes, through April 7.

Venus in Taurus: A Spectacular Pleiades Conjunction

2020: Venus approaches and moves past the Pleiades star cluster during late March and Early April. The closest date is April 3, 2020 when the planet is 0.3° to the lower left of the star cluster.

In late March, Venus moves into Taurus, heading for a conjunction with the Pleiades. During April, Venus moves between the Pleiades and Hyades and toward Elnath (Beta Tauri, m = 1.6), the Bull’s northern horn.  As Venus approaches the star, it begins a rapid descent toward the western horizon, toward its early June inferior conjunction.

On March 30,  Venus moves into Taurus, 3.6° to the lower right of Alcyone, the brightest star in the Pleiades star cluster.  The next evening, March 31, at the end of evening twilight, Venus, over 25° up in the west, is 2.7° to the lower right of Alcyone.

As April opens Venus is in the west near the Pleiades.  On April 3, one hour after sunset, Venus, 30° up in the west, is 0.3° to the lower left of Alcyone.  This is the closest Venus gets to the Pleiades on this evening appearance.

On the next evening, April 4, on this evening and for the next few evenings Venus and Sirius are at nearly the same altitude in the west at about 9 p.m. CDT in Chicago, a few minutes after the end of evening twilight (about 105 minutes after sunset). While Venus and Sirius are too far apart for technical comparisons of their brightness difference, the brightest star and the brightest planet are the same altitude in the western sky. Sirius, Orion’s belt, Aldebaran, and Venus are nearly in a line across the western horizon. The Venus – Alcyone gap, 0.9°.  Gaps as Venus moves eastward along the ecliptic and away from the Pleiades: April 5, 1.8°; April 6, 2.7°; April 7, 3.5°; April 8, 4.6°; April 9, 5.2°.

Venus moves between the Pleiades and the Hyades.  On April 9, at the end of evening twilight, Venus, nearly 25° up in the west-northwest, is below a line that extends from Aldebaran to Epsilon Tauri.  Venus passes nearly nearly 7° to the upper right of Epsilon Tauri on April 12.

 

Venus appears at its greatest brightness when it is midway between its greatest elongation and its inferior conjunction.

Venus continues to brighten from its first appearance in the evening sky.  Beginning April 13,  Venus reaches its maximum brightness until May 10. The midpoint, April 27, is marked on the setting chart (GB) near the beginning of the article. While the planet may grow brighter, as measured with detailed light measurements through a telescope, our eyes likely cannot perceive the minute difference in brightness during this duration. The planet reaches its latest setting time 11:33 p.m. CDT in Chicago, 243 minutes after sunset.  This setting time continues until April 18.

Venus continues its climb through Taurus.  On April 14, one hour after sunset, Venus, 30° up in the west, passes nearly 10° to the upper right of Aldebaran.  A week later, April 21, Venus sets at its northern most setting azimuth (309°). It sets here until May 14.

2020, April 26: The moon is to the left of Venus among the stars of Taurus..

As Venus continues through Taurus, it moves toward Beta Tauri, the northern horn of the Bull. On April 26, One hour after sunset, Venus, over 25° up in the west-northwest, is over 7° to the right of the crescent moon (4d, 14%). The planet is 5.5° to the lower right of Beta Tauri. The moon is 5° to the lower right of Zeta Tauri, the southern horn of Taurus.

Venus is at the interval of greatest brightness on April 27. On this evening, the waxing crescent moon (5.0d, 22%) is over 17° to the upper left of Venus. The planet has an elongation of 40°, and it is midway between its greatest elongation and inferior conjunction. Venus is at its greatest illuminated extent.  The illuminated portion of the planet covers the largest area of the sky. (For a more technical explanation of greatest illuminated extent, see https://tinyurl.com/venus-greatest-illuminated.) Venus closes in on Beta Tauri.  The gaps: Apr 27, 5.1°; Apr 28, 4.6°; Apr 29, 4.1°; Apr 30, 3.7°.

A Venus – Beta Tauri Quasi-Conjunction and a Venus – Mercury Conjunction

2020: Venus approaches but it does not pass Beta Tauri, the northern horn of Taurus, for a quasi-conjunction (near conjunction).  Look for Venus and the star about 60 minutes after sunset in the west-northwest.

During May, Venus rapidly descends toward the western horizon, as measured from its setting time compared to the sun. Venus is nearing its quasi-conjunction (or near conjunction) with Beta Tauri.  The gap between the brilliant planet and the star: May 1, 3.3°; May 2, 2.9°; May 3, 2.6°; May 4, 2.3°; May 5, 2.1°; May 6, 1.9°; May 7, 1.7°; May 8, 1.6°, May 9, 1.5°.

On May 10, Venus is at its closest approach to Beta Tauri, a quasi-conjunction or “near conjunction.” One hour after sunset, Venus, over 17° up in the west-northwest, is 1.4° to the lower left of the star.

The next evening, May 11, Venus is 30° east of the sun. The Venus – Beta Tauri gap is still 1.4°, but slightly larger than last night, when the small fractions of a degree are included in the measurement.  The Venus – Beta Tauri gap begins to widen:  May 12, 1.5°; May 13, 1.6°; May 14, 1.7°; May 15, 1.8°; May 16, 2.0°; May 17, 2.2°; May 18, 2.4°.

On May 19, Venus sets at the end of evening twilight, nearly 2 hours after sunset. Forty-five minutes after sunset, Venus, 11° up in the west northwest, is 2.7° from Beta Tauri.  As this celestial pair descends toward the western horizon during the next several evenings, Mercury emerges from the sun’s glare for its evening apparition.  This evening. Venus is 4.8° to the upper left of Mercury (m = −0.8).  Watching Mercury’s rapid movement during the next several evenings, you will see it move from Venus’ lower right to its upper left.

Venus is moving very rapidly toward the sun.  On May 20, Venus  is 20° from the sun. The Venus – Beta Tauri gap is 3.0° and bright Mercury is 2.8° to the lower right of brilliant Venus.  During the next few evenings, the Venus- Beta Tauri gap continues to widen: May 21, 3.4°; May 22, 3.8°.

Mercury closes in on Venus.  On May 21, Venus, in the west-northwest, is 1.1° to the upper right of bright Mercury, a conjunction. The Venus – Beta Tauri gap is 3.4°.

2020, May 22: Look for brilliant Venus, Mercury and Beta Tauri 45 minutes after sunset in the west-northwest.

On May 22, Venus, Mercury, and Beta Tauri make a compact triangle. Venus is 1.6° to the lower right of Mercury; Venus is 3.8° below Beta Tauri; and the Mercury – Beta Tauri gap is 3.4°. Tomorrow evening the moon enters the scene.

2020, May 23: The crescent moon joins Venus, Mercury, and Beta Tauri, 45 minutes after sunset.

During the next evening, May 23, at 45 minutes after sunset, Venus, about 8° up in the west-northwest, is 4.7° to the upper right of the crescent moon (1.3d, 2%). The Venus – β Tauri gap is 4.2°. Mercury  is 3.6° to the upper left of Venus and 3.1° to the lower left of Beta Tauri.

2020, May 24: The crescent moon appears to the upper left of Venus, Mercury and Beta Tauri 45 minutes after sunset. Note the changing positions of Venus and Mercury compared to the star.

This spectacle is not, yet, finished. On May 24,  Venus, bright Mercury , Moon (2.3d, 5%), and Beta Tauri are near each other. The planets and the star make a triangle.  Mercury is 5.5° to the upper left of Venus, nearly midway from Venus to the moon that is nearly 12° to the upper left of Venus, although Mercury is above a line that connects Venus and the moon.  Betai is 4.6° above Venus and 3.5° to the upper right of Mercury. Venus’ elongation from the sun is 15°.

The next evening, May 25, 45 minutes after sunset, Venus is 4° up in the west-northwest. The planet continues to make a triangle with Mercury and Beta Tauri.  Venus is 5.1° to the lower right of the star, while Mercury is 4.5° to the upper left of Beta Tauri. Venus sets at Nautical Twilight, over an hour after sunset.  The observing window is rapidly closing to see Venus.  The gaps of the two planets and star continue to grow as Venus disappears into brighter twilight.

Venus is now quickly disappearing into bright twilight.  On May 28, 30 minutes after sunset, Venus is less than 3° up in the west-northwest. The planet is  only 9° from the sun, setting only 49 minutes after sunset.

By May 30, Venus sets at Civil Twilight, 32 minutes after sunset.  Good-bye, Venus, for this appearance!

2020: June 3: Venus passes between Earth and sun (Inferior Conjunction).

On June 3, Venus is at inferior conjunction, 12:44 p.m. CDT, when it is 0.5° north of the sun and 58” across.

This evening apparition of Venus has several exciting conjunctions with planets and stars. As with every evening appearance, Venus slowly moves into the sky.  As the evening ecliptic takes a more favorable angle as the weather warms and daylight grows, the planet reaches its latest setting time and greatest brightness as Spring arrives. At this time, it has a spectacular conjunction with the Pleiades and a near-conjunction with Beta Tauri before it seemingly dives between our planet and the sun to reappear in the morning sky.  Early during the next apparition,  Venus has a double conjunction with Aldebaran and a traverse through the Hyades in a fairly dark sky.   It also passes several bright stars near the ecliptic including Regulus and Spica.  Appearances of Venus with the moon provide broader views of the sky.  As noted in the daily descriptions, Venus has conjunctions with Saturn and Jupiter, but they occur during bright twilight.   When the Venusian cycle repeats its motions in eight years, Venus goes into the Pleiades appearing nearly between Merope and Alcyone.

Astronomy, Feature, Sky Watching

2019, November 24: A Venus-Jupiter Conjunction
2016, August 27: A Venus-Jupiter conjunction.

Southern hemisphere readers, a chart for the conjunction appears at the bottom of this article.

As Venus emerges from the sun’s glare from its superior conjunction, Jupiter is heading toward its solar conjunction in late November 2019.  Venus passes Jupiter in a second conjunction between the two planets during this appearance of Jupiter that started late in 2018.

Venus is brighter in our sky because it is closer to Earth, so it appears larger in the sky than Jupiter.  Clouds cover this nearby planet and they reflect over 75% of the sunlight that hits them.  Farther Jupiter reflects about 50% of the sunlight that reaches its clouds.  The result is that Venus is about 3 times brighter than Jupiter, the two brightest “stars” in the southwest.

Here’s how to see the event

The passing of these two planets is a slow moving show that occurs over several nights.  First, find a clear horizon in the southwest, free from trees, houses, buildings, and other possible obstructions.

In the charts that follow, several of them are displayed for a time interval after sunset.  Use local sources for the time of your sunset.  The U.S. Naval Observatory has an online calculator that displays a year of sunrises and sunsets.  Enter your state and city into Form A on the website. For readers outside the U.S., enter your longitude and latitude in Form B for your yearly table.  Click here.

Start looking for Venus and Jupiter about 30 minutes after sunset. A binocular may help with the initial identification of the two planets.  After that first observation go outside at about the same time each evening.

While low in the sky, Venus is the brightest object in the southwest.  If you live near a busy airport, the planet’s visual intensity rivals lights on airplanes.  Wait for a minute, you’ll see the airplane move through the region. Venus will seem to hang there.  Jupiter is not as bright, the second brightest starlike point of light to Venus’ upper left.  Each evening until November 24, Venus gets closer to Jupiter.

Begin looking in late October when the moon is near Venus.

2019, October 29: The crescent moon appears near Venus. Jupiter is to the upper left of Venus and the moon.

The moon makes its first appearance with Venus on October 29.   Thirty minutes after sunset, the moon appears to the upper left of Venus, only 4° up in the southwest with bright Jupiter to the upper left of the pair. The moon is 1.8 days old, past its New phase, and 4.4% illuminated.  The moon appears with Jupiter two evenings later (October 31).

2019, November 13: The Venus-Jupiter gap is 10°.

On November 13, thirty minutes after sunset, the Venus – Jupiter gap is over 10°. (Your fist, at arm’s length, is about 10 degrees from the knuckle of your thumb to the knuckle of your pinky finger.)  Venus is 6° up in the southwest.  Look for the planets each clear evening during the next several evenings.

2019, November 19: Look low in the southwest for Venus and Jupiter about 45 minutes after sunset.

In about a week, the gap closes between the planets. On November 19 their separation is about 5°.  About 45 minutes after sunset, Venus is 4° up in the southwest.

The Venus continues to close in on Jupiter. The separations until the conjunction:

  • Nov 20, 3.9°;
  • Nov 21, 2.8°;
  • Nov 22, 2.1°;
  • Nov 23, 1.5°, Venus is to the lower left of Jupiter.  The pair is nearly as close as they are tomorrow evening.
2019, November 24: Venus-Jupiter conjunction!

On  the evening of November 24, Venus and Jupiter appear closest! Forty-five minutes after sunset, Venus, nearly 7° up in the southwest, is 1.4° to the lower left of Jupiter.  The separation has the same distance as three times the moon’s apparent size in the sky.  Not the actual size, but the size the moon appears in the sky. The planets appear close together in the sky, but Venus and Jupiter are over 430 million miles apart, over 4 times the earth’s distance from the sun.

Now watch Venus appear to separate and move away from Jupiter.  The separations after conjunction:

  • Nov 25, 2°, Venus is to the left of Jupiter;
  • Nov 26, 2.8°;
  • Nov 27, 3.7°, Venus is to the upper left of Jupiter;
  • Nov 28, 4.7°

Next Venus moves toward a conjunction with Saturn on December 10.

In the Southern Hemisphere

For our southern hemisphere readers:  The chart above shows the Venus-Jupiter conjunction about 45 minutes after sunset as seen from the latitude of Sydney Australia, looking west-southwest.  Venus and Jupiter are 1.4 degrees apart with Saturn to the upper right. At this time Venus is about 20% of the way from the horizon to overhead.  As with northern hemisphere observers, use local sources for the time of sunset.

Venus-Jupiter Conjunctions, 2021-2024

Conjunctions of Venus and Jupiter are frequent, but approximately a year apart beginning with a difficult-to-see conjunction in 2021.  The following table provides explanation of the upcoming meetings.

Date Separation When Description
February 11, 2021 26’ Morning This pairing is very difficult to see in the eastern sky as the planets rise in bright twilight just 25 minutes before sunrise.
April 30, 2022 29’ Morning The planets rise in the eastern sky about 90 minutes before sunrise.  In separation, this rivals the gap of the June 2015 conjunction, although it is lower in the sky.
March 1, 2023 32’ Evening This conjunction rivals the June 2015 pairing, with the planets high in the west after sunset, setting 2 hours, 30 minutes after the sun.
May 23, 2024 15’ Morning This pairing is impossible for casual observers to see as it occurs when the planets are nearly behind the sun hidden in the solar glare.