September 6: In the predawn eastern sky, the waning crescent moon (26.0 d, 15%) is on a virtual line that connects the Gemini Twins, Castor (α Gem, m = 1.6) and Pollux (β Gem, m = 1.2). The moon is 9.2° from Pollux. Thirty minutes before sunrise, with binoculars, look in the east-northeast for Mercury (m = −1.1) 1.2° to the left of Regulus. Mercury is 6.5° up in the sky.
In the evening sky, Saturn’s retrograde ends. It is 5° to the upper right of Kaus Borealis (λ Sag, m = 2.8), the star at the top of the lid of the Teapot of Sagittarius, and 45° from Jupiter. Mars and Jupiter have the same visual brightness (m = −1.9). Because they have distinctly different colors, do they appear to be the same brightness to you? While they are over 70° apart, it is not appropriate in formal astronomy to compare respective objects’ brightness, but it is a fun activity. Look near the end of twilight because they have nearly the same altitude early in the evening.
September 1: Mercury (m = −9) is 10° up in the east-northeast, 30 minutes before sunrise. It is approaching a conjunction with Regulus (α Leo, m = 1.3). This morning Regulus is 7.8° below Mercury, and very difficult to locate, even with optical assistance and a perfect horizon.
In the evening sky, for most of the month, Venus (m = −4.7) and Spica (m = 1.0) set at nearly the same time, 85 minutes after sunset this evening. As they separate, Venus moves farther south. (Recall that the farther north an object the longer it stays in the sky.) As they slide into twilight the largest time gap in their setting times is 15 minutes. Jupiter (m = −1.9) is 24° to the upper left of Venus. (If the Martian dust storms subside,) At 10 p.m. CDT, when Mars is near the meridian about 22° up, it may provide excellent telescopic views. Mars moved into the boundaries and in front of the sidereal backdrop of Capricornus.
While Venus shines in the western sky, Jupiter and Saturn appear in the southern sky with Antares between them. The star is the brightest star in Scorpius.
Bright Jupiter, in the south-southwest, appears to the upper right of Zubenelgenubi. Watch Jupiter approach and pass the star during the next month.
Saturn, just past its opposition, shines in the southeast, is 52 degrees to the lower ft of Jupiter.
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Look for 5 planets during the month. From mid-northern latitudes, they are not visible simultaneously. Look for Mercury about 30 minutes after sunset with binoculars, then wait for Mars to cross the southeastern horizon. Four bright planets then span the sky from Mars to Venus. Mars reaches its opposition later in the month. The planet is closer than it’s been since 2003.
Click here for the blog’s table of contents
Look for 5 planets during the month. From mid-northern latitudes, they are not visible simultaneously. Look for Mercury about 30 minutes after sunset with binoculars, then wait for Mars to cross the southeastern horizon. Four bright planets then span the sky from Mars to Venus. Mars reaches its opposition later in the month. The planet is closer than it’s been since 2003.
July opens with the waning gibbous moon in the south-southwest. Mars, now the second brightest planet, is 25° up in the south-southwest, 5.8° below the moon. At the same time, Saturn is 10° up in the southwest. With both planets near their oppositions, they appear in the southeastern sky during the evening and move westward during the night. During the early evening, four bright planets are arched across the sky, with the trio of bright outer planets in retrograde.
One hour after sunset, brilliant Venus stands 14° up in the west. Venus is 9° to the lower right of Regulus. Watch Venus close in and pass Regulus during the first 9 days of the month. At this hour, dimmer Mercury is 4° up in the west-northwest, setting nearly 90 minutes after sunset. Use binoculars to locate it. This speedy world approaches its greatest elongation during the first half of the month.
Meanwhile, bright Jupiter, 82° to the upper left of Venus, is 33° up in the south. This giant planet is 2° west of Zubenelgenubi. Saturn, just past its opposition and retrograding above the Teapot of Sagittarius, is 13° up in the southeast, 52° to the lower left of Jupiter.
Mars, racing toward its opposition later in the month, rises in the southeast 117 minutes after sunset. The Red Planet, retrograding in Capricornus, appears 34° to the lower left of Saturn. Start looking for the five naked eye planets during the early evening. Look for Mercury during twilight, then wait for Mars to clear the southeast horizon. Here are the highlights for the first half of the month:
In early July, Venus passes the next signpost of the ecliptic, Regulus. This vivid blue star is less than one degree from Venus on July 9.
At mid-month, Venus continues to dominate the evening sky with its brilliance. At 65 minutes after sunset, Venus is 11° up in the west, setting about an hour later. Venus is now 6.5° to the upper left of Regulus. On July 15, the waxing crescent moon is 1.5° to the lower right of Venus. Mercury, now past greatest elongation and fading quickly into the sun’s glare, sets 71 minutes after sunset. Use binoculars to catch it in bright twilight. Jupiter, near Zubenelgenubi, is 30° up in the south-southwest. Saturn, 19° up in the south-southeast, is 51° to the lower left of Jupiter. Mars, the second brightest “star” and rising 65 minutes after sunset, is approaching its perihelic opposition. It is 18° up in the southwest 2 hours before sunrise. Here are the highlights for the second half of the month:
July 16: The waxing crescent moon is 11.9° to the upper left of Venus. The Venus-Regulus gap is 7.7° and growing each day.
The month ends with four bright planets lined up across the early evening sky. Brilliant Venus is 9° up in the west 70 minutes after sunset. Mars is 7° up in the southeast. Mars retrogrades until August 27. It is 30° to the lower left of Saturn, 23° up in the south-southeast, above the Teapot of Sagittarius. It retrogrades until September 6. This ringed wonder is 49° to the left of Jupiter. Jupiter is 26° up in the southwest, 1.5° to the right of Zubenelgenubi. Watch this giant world narrow the gap to the star and pass it next month. Jupiter is 50° to the left of Venus.
Less than a month before its opposition, Jupiter gleams from the southwest this morning. The planet is now rising in the east-southeast at about 10 p.m. Jupiter is retrograding near the star Zubenelgenubi.
Mars and Saturn are farther east, beyond the star Antares. Saturn rises before 2 a.m. with Mars following closely behind. Saturn’s opposition is in June. Mars’ opposition is July, three oppositions in 79 days.
This morning Mars and Saturn are about 4 degrees apart. Saturn begins to retrograde in a week (April 17).
The waning crescent moon (24 days old) is low in the east-southeast this morning, outside the frame of the planets.
The articles that follow provide details about the planets visible without optical assistance (binoculars or telescope):
For about a month near the summer solstice, five planets are visible during the early evening, but they are not easily visible simultaneously from mid-northern latitudes. As the sky darkens a parade of planets extends across the sky from brilliant Venus in the west to Mars in the southeast. The “X” factor of seeing 5 planets simultaneously is Mercury. It reaches its greatest elongation on July 12, although Mercury is visible throughout its apparition.
For more southerly locations in the United States and farther southern latitudes, see this article: 2018: Five Planets Visible at Once
Here’s how to look for the five planets:
June 16, 2018: Start looking for Mercury early it its apparition, although the rising time for Mars is much later. From an observing location with a clear horizon, locate the speedy planet Mercury 30 minutes after sunset. Mercury sets 63 minutes after sunset, 15 minutes before Nautical Twilight (sun’s altitude is -12°). Mars rises in a dark sky nearly 3 hours after sunset. At 30 minutes after sunset on this evening, Venus is 25° to Mercury’s upper left. The waxing crescent moon (3.3 days old) is 7.9° beyond Venus.
July 2: Again with binoculars first locate Mercury 10° up in the west-northwest 30 minutes after sunset with brilliant Venus 16.6° to Mercury’s upper left. Regulus is 8.1° beyond Venus. Mars touches the east-southeast horizon 25 minutes after Mercury sets and 15 minutes before the end of twilight.
July 12: At sunset, Mercury is 13° up in the west-northwest. Thirty minutes later, it has an altitude of only 8.5° with brilliant Venus 16.4° to its upper left. Venus is 3.4° beyond Regulus. Mercury sets 78 minutes after sunset and Mars touches the southeast horizon at the same time. Locate Mercury, then wait until Mars clears the east-southeast horizon.
July 17: The best evenings for seeing all five planets are around this date, but you’ll need optical assistance. Thirty minutes after sunset, dimmer Mercury is 5.1° above the horizon. Mercury is dimmer as the apparition continues so optical aid is needed to first locate it. Regulus is 9.5° to the upper left of Mercury with Venus 8.5° beyond the star. Mars rises six minutes before Mercury sets, although both are low in the sky. Twilight lingers for over 2 hours at this time of the year at mid-northern latitudes.
On July 17, 2.5 hours after sunset and after Mercury sets, the planet parade arches across the southern sky. Brilliant Venus sparkles 5° up in the west and Mars is 5° up in the southeast. Saturn is 32.8° to the upper right of Mars, above the Teapot of Sagittarius. Jupiter is 50.8° to the west of Saturn and 1.8° to the west of Zubenelgenubi. The moon (5.0 days old) is nearly between Venus and Jupiter.
Another opportunity to see five planets simultaneously, from mid-northern latitudes, occurs in the morning near the time of the summer solstice in 2020. While these groupings are infrequent, they provide magnificent displays of the solar system’s beauty.
