Extra Content

Sometimes on the Sky Calendar, additional additional files, extended notes, and other activities are mentioned. They can be found here and are provided by Robert C. Victor, Robert D. Miller, and Jeffrey L. Hunt for those who find them useful.

Robert C. Victor originated the Abrams Planetarium monthly Sky Calendar in 1968, still assists in its production occasionally, and writes a monthly column on skywatching for the Coachella Valley Independent. He enjoys being outdoors, sharing the beauty of the night sky and other natural wonders.

Robert D. Miller, who provided the monthly evening and morning twilight charts, did graduate work in planetarium science, and later astronomy and computer science at Michigan State University. He remains active in research and public outreach in astronomy.

Jeffrey L. Hunt, who provided the graphs of morning planets’ rising times and evening planets' setting times for 2026, is a retired planetarium director now living in the Chicago area. He has taught astronomy and sky watching to people of all ages. He studied astronomy education at Abrams Planetarium at Michigan State University. Jeffrey writes an astronomy blog at jeffreylhunt.wordpress.com and can be followed on Twitter at @jeff_hunt.

Sky events in September 2026, and a spectacular predawn occultation of Jupiter on October 6.

Throughout September 2026, all five outer planets of our solar system — those farther from the Sun than the distance sunlight travels for 8.3 minutes to reach our home planet — form a long lineup across the predawn sky. Three are clearly visible as bright "stars" to the unaided eye. The waning Moon fits within the lineup during Sept. 1-8, and again during Sept. 27-Oct. 5. In order, the Moon and bright planets within the lineup, from west to east one hour before sunrise on Sept. 1, are:

Saturn, of mag. +0.5, in Pisces in SW;

Moon, in waning gibbous phase, 80 percent full, in Aries 18° above Saturn in SW;

Mars, of mag. +1.3, in central Gemini in east, forming a nearly isosceles triangle with the "Twin" stars, Pollux and Castor, within 12° to its lower left; and

Jupiter, of mag. –1.8, brightest morning "star", in Cancer, low, between east and ENE, 30° to Mars' lower left.

Because of the Earth's faster revolution around the Sun, all of these distant planets, along with the entire field of stars, will drift from east to west across the sky as weeks pass. The motion is depicted on our morning twilight sky map for this month.

But if you watch closely, you can see these planetary bodies also have their own motions against the background. The Moon is close to us, completing one circuit around the Earth with respect to background stars in 27.3 days, so its change in position is obvious from one day to the next, averaging 13.2° per day, always eastward. On Sept. 3, the 60-percent Moon will appear very close to the Pleiades star cluster. Use binoculars to see some of its members close to Moon's lower left. Close, but not really! — Light from the Pleiades takes about 440 years to reach us, but light reflected from the Moon that morning takes only 1.2 seconds to get here. Bright Aldebaran, southern eye of Taurus, is 15° to Moon's lower left. Just 3° upper right of Aldebaran lies 3.5-mag. Ain, or Epsilon Tauri, or Oculus Borealis, the northern eye of the Bull. The V-shaped asterism forming the head of Taurus includes both these stars, at the tips of the "V", but Aldebaran, 67 light years away, is not really a member of the physical group called the Hyades, which includes the rest of stars of the "V", and some other stars, all at a distance of about 150 light-years from our solar system. Visualize the sky in three dimensions as you enjoy these scenes!

An hour before sunup on Sept. 4, the Moon, 49-percent full and just past Last Quarter phase, within 90° west of the Sun, will be farther along in Taurus, within 10° west (upper right) of 1.7-mag. Elnath, tip of the Bull's northern horn. This morning, Jupiter is 61° east of the Moon, and Saturn is 60° to Moon's west, so the Moon on Sept. 4 appears midway between Saturn and Jupiter. The lineup Saturn-Moon-Mars-Jupiter is 121° long, and Mars is spotted 32° east of the Moon, and 29° west from Jupiter, or just over halfway from the Moon toward Jupiter. Actual distances from Earth, expressed as light-travel times, in minutes, from each planet to Earth on the morning of Sept. 4, are Saturn, 71 minutes; Mars, 15; and Jupiter, 51. Compare to the closest and brightest star visible in the predawn sky on that morning, Sirius, the Dog Star, in the southeast: The star is 8.6 light-years away.

If you want to build a scale model of our solar system in which one inch represents the distance between Earth and Sun, defined as one astronomical unit, and place stars in the same model, then one mile would represent one light-year, and Sirius would be 8.6 miles away — in the model! This works because the number of astronomical units in a light year is very nearly the same as the number of inches in a mile, about 63,000. Neptune, the most distant known planet of our solar system at four light-hours from the Sun, would be 2½ feet away from the Sun in the scale model. The Pleiades star cluster would be placed some 440 miles away, and it's just a near neighbor within our Milky Way Galaxy.

On the morning of Sept. 6, the 27-percent Moon will have company: Mars 5° below, and the Twin stars of Gemini, Pollux and Castor, within 11°-12° to its lower left. On Sept. 7, the 17-percent Moon will lie within the triangle formed by Mars, Pollux, and Jupiter. Can you spot the star Regulus, heart of Leo, the Lion, 15° lower left of Jupiter this morning? Binoculars may help you spot this star emerging from the glare of twilight. It appeared on the far side of the Sun just 15 days ago, on Aug. 23, and owing to the Earth's revolution around the Sun, it is now visible, and climbing nearly 1° higher each morning!

Stars rise two hours earlier each month, so by late February, Regulus will rise at sunset and be visible all night. Mars and Jupiter will remain nearby through mid-2027, forming interesting gatherings with each other and with Regulus. Mars will pass Regulus three times in an event called a triple conjunction. There'll be some quasi-conjunctions where a body makes an approach, but doesn't follow through. [Have you ever seen that happen?] We'll keep you posted. Check the illustrations on the Sky Calendar, available by subscription for $12 per year, from https://abramsplanetarium.natsci.msu.edu/sky-calendar/

On Sept. 8, Jupiter appears 4° lower left of the 9-percent crescent Moon. Use binoculars before twilight brightens to spot the Beehive cluster 3° to Moon's upper right. From East Lansing, Michigan, the Moon will occult Jupiter that day for 61 minutes beginning at 2:50 p.m. EDT, but the event, only 31° from the Sun, will be very difficult to observe in broad daylight, because of the low surface brightnesses of the 7-percent crescent Moon and of distant Jupiter. But the next occultation of Jupiter, in predawn darkness on October 6, will be spectacular! (See below.)

On Sept. 9, find the 4-percent, old crescent Moon 10° lower left of Jupiter, and then try for Regulus, just 5° to Moon's lower left. This will likely be your last chance to spot the Moon in the morning until the closing days of the month, when the Moon will reappear in the west. In the interim, watch Mars, moving east about 0.6° per day, pass within 6° south of Pollux on Sept. 17, and, crossing into Cancer on Sept. 25, form a 12°-long straight line with the Twin stars. (Pollux and Castor are 4.5° apart.) Jupiter, as it crosses from Cancer into Leo on Sept. 24, is then within 12° from Regulus and closing in by less than 0.2° per day, and slowing down. It'll be interesting to see what happens; stay tuned!

Saturn is retrograding this month, moving east to west against the stars. Although it crossed into Cetus on Sept. 5, it is now just south of a pair of 4th-mag. stars Delta and Epsilon in Pisces. Watch for changes in the shape of the triangle Saturn forms with those stars as Saturn retrogrades a total of less than 7° between late July and mid-December 2026. A telescope shows the planet's rings temporarily closing toward edgewise until early December, when they'll be 6° from edge-on before opening again. They'll be at maximum open, to nearly 27°, in 2032.

In dark predawn skies, Uranus at mag. 5.7 is now an easy target for binoculars. It begins retrograde on Sept. 10, and barely moves all month. Using binoculars on dark mornings, find five objects in a nearly straight line, 10¾° long, joining 2.9-mag. Alcyone, or Eta Tauri, brightest member of the Pleiades, to 3.5-mag. Ain, or Epsilon Tauri, Bull's northern eye in the Hyades, described above. In order from WNW to ESE, counting the endpoints of the line, they are: Eta; next go 4.3° ESE to 4.4-mag. 37 Tauri; next go 2.5° ESE to 5.8-mag. Uranus; next, go 0.95° ESE to 4.9-mag. Omega-2 or 50 Tauri; and finally, go 3.0° ESE to Epsilon.

Neptune at mag. 7.8 is more challenging. During September it is WSW of Saturn by 10.1° to 8.8°. Look between the Circlet of Pisces and Iota Ceti for a 1° by 3° rectangle of stars forming the body of Testudo, the Turtle. The upper two stars of this asterism, 29 and 27 in Pisces, are of mag. 5.1 and 4.9, and within 1° apart. Three degrees lower are the stars 33 and 30 in Pisces, of mag. 4.6 and 4.4, also within 1° apart. Binoculars show the entire rectangle easily fitting within a single field. The 5.1-mag. star 29 in Pisces is the northeastern (upper left) member of the rectangle. In September, Neptune retrogrades 0.8°, and appears northeast of 29 Psc, by 4.3° to 3.6°. Neptune passes opposition on Sept. 25 (unfortunately with a bright Moon nearby), and transitions into the evening sky. Saturn will pass opposition at mag. +0.3 on the night of Oct. 3-4.

Evening Sky: Venus reaches greatest brilliancy at mag. –4.8 in late September, but gets quite low as the month progresses. Find it as soon as you can right after sunset, or even before, and that'll be a good time to examine it with optical aid, even binoculars, to resolve the ever-thinner, ever-larger-in-apparent-diameter crescent, as the planet approaches Earth before next month's swing between Earth and Sun, called inferior conjunction. During September, Venus changes from a 38-percent crescent, 31" (arcseconds) across, to 15-percent, 49" across, as the Venus-to-Earth light travel time shrinks from 4.5 minutes to 2.9 minutes, ending the month closer than any other planet can ever be. (The speed of light is about 11.2 million miles per minute.)

The pairing of Venus and Spica, 1.5° apart on Sept. 1, is the first of a triple conjunction between the two bodies, but the next two, in the morning sky in November, will have only a single minimum separation associated with the second and third conjunctions, within 1.2° apart on Nov. 9, as Venus makes a tight loop around the star.

While Venus and Spica are still in the evening sky, zero-mag. Mercury passes just 1° north (upper right) of first-mag. Spica on Sept. 25. But by then, Venus will be lower, and Spica will be mired very low in bright twilight 14° to Venus' lower right. Mercury, near mag. 0 early in this very poor evening apparition, might then be seen through binoculars low in bright twilight, but fainter, first mag. Spica, even lower, likely not. Venus will reach its maximum distance of 15° east of invisible Spica on Oct. 3, when Mercury will be 6.5° to Venus' upper right. But by then from northern states, Venus will set too early in bright twilight to be of use for locating Mercury.

Moon in evening sky: On Sept. 12, the 4-percent crescent Moon sets in very bright twilight, 18°-19° lower right of Venus. With the ecliptic making its smallest angle with the horizon at dusk this time of year and the Moon nearly 5° south of the ecliptic tonight, it will be a challenge to spot the Moon even though it’s 23° east of the Sun. From northern U.S., in very clear skies about 15 minutes after sunset tonight and an unobstructed view about 15° south of west, you can try with binoculars. While you’re out searching for the young Moon, take a moment to aim your binoculars at Venus and note its 30-percent crescent, resolvable in a bright sky. Spotting the Moon this evening will be easier for observers at lower latitudes.

On Sept. 13, about 40 minutes after sunset, catch a 9-percent waxing crescent Moon low in WSW, 6° lower right of Venus and 4° lower left of Spica. On the next evening, Sept. 14, find the 16-percent crescent Moon 6° upper left of Venus.

In mid-September, one hour after sunset, ranking next after Venus in brightness are two zero-magnitude stars, golden Arcturus in west, and blue-white Vega overhead. On Sept. 16 and 17, the Moon will be a fat crescent in SSW, near the first-magnitude red supergiant star Antares, heart of the Scorpion. Other bright stars at dusk are Altair and Deneb, completing the Summer Triangle with Vega. Just before the end of twilight in mid-September, watch for the appearance of Fomalhaut, Mouth of the Southern Fish, rising in SE, and Capella, the Mother Goat star, rising in NNE. The Moon is Full in the daytime on Sept. 26, yet will still rise just before sunset. As the sky darkens that Saturday evening, look for Saturn 6° lower left of the Moon. This outermost of the bright planets remains about the same angular distance from the Moon through the rest of that night, until dawn on Sunday, Sept. 27.

Harvest Moon effect: After the Full Moon of Sept. 26, each evening through October 1, the Moon rises farther north along the horizon daily, making its rising occur not much later each night for a few evenings after Full from mid-northern latitudes. On Sept. 27-29, the first three evenings after Full Moon, moonrise occurs before the end of twilight, allowing no fully dark skies anytime during those nights.

Back in the morning sky: An hour before sunrise in the closing days of September, Orion stands high in the south. Note his 3-star belt, midway between the constellation's brightest stars, red Betelgeuse and blue-white Rigel, points lower left to Sirius, and upper right past Aldebaran and the Hyades to the Pleiades. Procyon completes the almost equilateral Winter Triangle with Sirius and Betelgeuse.

Capella, northernmost of the stars of first-magnitude or brighter, passes north of overhead at nearly the same time that Rigel, Orion's foot, reaches its high point in the south. From southern U.S., the second brightest star, Canopus, is then already visible very low in SSE. It passes due south about 21 minutes before Sirius does. Seen from latitude 34° N (Atlanta, Palm Springs in the southern California desert, and Los Angeles), Canopus reaches its highest point, only 3°-4° above the southern horizon, in darkness hours from mid-October (as dawn twilight begins) through early March (at nightfall).

In the morning sky during Sept. 30-Oct. 7, the Moon will slide past, in order from west to east, the Pleiades, the Hyades, Aldebaran, and Elnath, all in Taurus; Castor and Pollux in Gemini; Mars and the Beehive cluster in Cancer; and Jupiter and Regulus in Leo.

On Tuesday, October 6, there will be a spectacular predawn occultation of Jupiter by a 20-percent crescent Moon for much of the U.S. except the far West. This is an early head’s up, so you can mark the event on your calendar! For a world map with times of disappearance and reappearance of Jupiter for cities in Canada, Mexico, and United States, go to

http://www.lunar-occultations.com/iota/bstar/1006jupiter.htm

Scroll down the two lists (one for Jupiter’s disappearance times, and one for the reappearance times) to data for cities in CA, MX, or US, and convert the provided Universal Times for your city to your own time zone. By subtracting 4 hours from UT to obtain EDT, for example, we find that for Lansing, Michigan, Jupiter disappears behind the lower, sunlit edge of the Moon at 4:23 a.m. EDT (Moon 13° up, 9° north of east). On the second list, we find that Jupiter reappears from behind the lunar crescent’s dim, earthlit upper edge nearly an hour later, at 5:19 a.m. (Moon 23° up, and due east.) The reappearance at the dark edge of the Moon will be really spectacular! The quantity CA listed for each event is the cusp angle, the distance from the northern or southern cusp, or endpoint of the crescent. The negative value of –66N given for the disappearance tells us that Jupiter disappears along the sunlit limb, 66 degrees along the Moon’s circumference from the northern cusp. The positive value 64N given for the reappearance tells us that Jupiter reappears along the dark limb, 64 degrees along the circumference from the northern cusp. Because Jupiter presents a disk more than 30 arcseconds across, the immersion and emersion will each last more than 60 seconds.

Expanded August 2026 observing notes

August skywatching highlights: Venus, the evening star, is of increasing interest for telescopic viewing. See up to four bright planets and 11 stars of first magnitude or brighter before dawn. In the predawn hours of Aug. 13, the annual Perseid meteor shower is at its best. The Milky Way excels in August, whenever skies are dark and moonless, but the section toward our galaxy's rich, central region, in the constellations Sagittarius, Ophiuchus, and Scorpius, is best observed at the end of evening twilight.

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A solar eclipse on Wednesday, August 12 will be seen as total within a path crossing the Arctic Ocean, parts of Greenland, Iceland, and Spain, but will be only a minor partial solar eclipse for observers in mid-Michigan. From East Lansing, MI, the eclipse starts at 1:02 p.m. EDT, as the Moon's disk begins to encroach upon the Sun's. Greatest eclipse for East Lansing occurs at 1:33 p.m. EDT, when the Moon will block the lower 7.4 percent of the Sun's diameter, and 2.4 percent of the area of the solar disk will be covered by the Moon. The Moon exits the solar disk at 2:03 p.m. EDT. In North America, the partial solar eclipse will be visible only everywhere north of a line passing near Vancouver, BC, Chicago, IL and Raleigh, NC. From places south of that southern limit, no eclipse will be seen.

For a world map of the August 2026 solar eclipse and predictions of beginning and end times and fraction of Sun covered, for any location:

http://xjubier.free.fr/en/site_pages/solar_eclipses/TSE_2026_GoogleMapFull.html

For important tips from the American Astronomical Society on how to safely view a solar eclipse, including a list of suppliers of safe solar viewers and filters:

https://eclipse.aas.org/eye-safety

Interestingly, the next total solar eclipse to be visible at a location within the contiguous 48 United States will occur 18 years 11.3 days (one Saros interval) later, on August 23, 2044. In that event, the total eclipse, after traveling from Greenland through northern and western Canada, will occur just before sunset in Montana and North Dakota, one-third of the way around the world from this month's total solar eclipse which ends at sunset in the Mediterranean Sea, just off the coast of Spain. Within a year after the 2044 eclipse, on August 12, 2045, a very long total solar eclipse will track from coast to coast across the U.S. from northern California to Florida. Mark the date on your calendar, and make plans to be there! The 2045 eclipse is a member of Saros 136, which includes a streak of eclipses with totalities in the 20th through mid-21st Centuries lasting more than 6 minutes. The longest totality of the series was 7 minutes 08 seconds, in 1955. The most famous eclipse of this series occurred on May 29, 1919, when subsequent measurements of the shifts of images of the stars of the Hyades cluster in photographs of the field around the eclipsed Sun confirmed predictions of Albert Einstein's General Theory of Relativity.

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A deep partial lunar eclipse on Thursday night, August 27-28, has a peak of 93 percent of Moon's diameter immersed in the dark core or Earth's shadow at 13 minutes after midnight Eastern Daylight Time early on Friday morning August 28, or simultaneously at a more accessible local time for observers in western states, on Thursday evening at 9:13 p.m. PDT. More details are provided below.

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Mornings this month are prime for sky-watching. The month begins with the Moon and three planets in a long lineup across the sky within the belt of zodiac constellations. On August 1, their arrangement from west to east an hour before sunup, is: Capricornus about to set in WSW; Moon in SW in Aquarius; Saturn high in south in Pisces; the compact Pleiades star cluster well up in the east, with ruddy Aldebaran, eye of Taurus, nearly 14° below, closely accompanied by stars of the Hyades cluster, completing a letter "V" marking the head of the Bull. Both star clusters are very rewarding sights through binoculars! The red planet Mars, also in Taurus, 14° lower left of similarly-colored Aldebaran on Aug. 1, shifts position against the star background by about two-thirds of a degree daily, passing between the Bull's horns on Aug. 2-3. Look daily and notice the change, which will bring Mars into Gemini by Aug. 12. The easternmost visible planet in the morning sky in early August is Mercury, found very low in ENE, 27° lower left of Mars on the first few mornings. Before mid-August, Jupiter will emerge to mark the east end of a 4-planet lineup.

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The Moon is the fastest-moving zodiacal wanderer, shifting its position eastward by a daily average of 13.2° per day, completing one trip around the zodiac in 27.3 days. Because of the Sun's apparent motion of nearly 1° per day against the zodiacal backdrop — the result of the Earth's orbital revolution around the Sun — it takes an extra 2.2 days for the Moon to catch up and pass the Sun twice in succession. This causes a cycle of lunar phases, from Full Moon to Full Moon for example, to take up 29.5 days.

Go out each morning in early August, to follow the waning Moon, passing Saturn on August 3 and 4, and passing just below the 2nd- and 3rd-magnitude pair of stars of Aries, the Ram on Aug. 5. By Aug. 6, the Moon is a fat crescent, to upper right of the Pleiades. If you get out very early the next morning, Aug. 7, not long after moonrise and the midnight start of the day, you can catch the Pleiades cluster very close to the Moon's earthlit upper limb (which will uncover some stars of the cluster from places in eastern U.S. and Canada), and watch the Moon pull away from the cluster until morning twilight intervenes.

An hour before sunup on Aug. 8, the crescent Moon cozies up to the tip of the Bull's northern horn, with Mars below. On Aug. 9, a thinner crescent Moon will appear closer to the red planet, about 5°-6° to Mars' lower left. On that same morning, look to the lower left of the Moon for three objects arranged in a diagonal straight line. From lower right to upper left, they are: Mercury, the brightest; Pollux, 6° to Mercury's upper left; and Castor, the faintest, 4.5° to Pollux's upper left. On the morning of Aug. 10, one hour before sunrise, the 7-percent crescent Moon appears 6°-7° to the right of the "Twin" stars Pollux and Castor, 19° lower left of Mars, and 13° upper right of Mercury. On August 11, the Moon's last morning, look for the 2-percent thin crescent old Moon very low in ENE, with Mercury closely lower right of the center of the Moon's disk, by 1.7° from the Moon's center as seen from Palm Springs, or 2.0° as seen from East Lansing. Binoculars will give the best view. If the sky is very clear and you have an unobstructed view in that direction, keep watch with binoculars for the next 15 to 30 minutes, until you can see Jupiter 6° below and slightly left of the Moon-Mercury pair. Each successive morning, Mercury, heading toward superior conjunction on the Sun's far side on Aug. 27, drops a little lower, while Jupiter, emerging from solar conjunction because of Earth's faster orbital motion, climbs higher. By Aug. 15, the two planets will appear nearly the same height above the horizon, with fainter Mercury passing within 0.6° to the north (left) of Jupiter. You can fit them in the same telescope field! Within a few days later, Mercury will be gone, and Jupiter will be the dominant morning "star" until emergent Venus dethrones it at the end of October.

The Moon returns to the morning on August 27, when it's Full and low in WSW an hour before sunup. Then the lineup of bright zodiacal objects from west to east will be Moon, Saturn, Aldebaran, Mars, Pollux a bit to the north of the solar system's plane, and Jupiter. The waning gibbous Moon will glide past Saturn on Aug. 30 and 31. On August 31, Mars. in central Gemini, will form an isosceles triangle with Pollux and Castor, 12° from each.

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Other bright objects in the morning sky include, north of the zodiac plane, the Summer Triangle of Vega, Altair, and Deneb in W to NW, beginning to set in twilight in latter half of month, and Capella, the "Mother Goat" star, ascending in NE. South of our solar system's plane, look for Fomalhaut, Mouth of the Southern Fish, far to the lower right of, or below, Saturn. Orion, with his 3-star belt flanked by red Betelgeuse and blue-white Rigel, has already emerged into the eastern sky by the start of August. Before midmonth, watch for the rising of Procyon, the "before the Dog" star, rising just north of east to lower left of Betelgeuse, and Sirius, the Dog Star itself, also the brightest nighttime star, rising in ESE, nearly in line with Orion's belt extended downward. Sirius, Procyon, and Betelgeuse form the nearly equilateral Winter Triangle. Capella, northernmost of the 21 stars of first magnitude or brighter, can be located midway between Orion's belt and 2nd-magnitude Polaris, the North Star.

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The best occasions for viewing the Milky Way in the morning before twilight begins are the moonless predawns of August 11-24, when the Milky Way will be seen in the Summer Triangle in W to NW, up through Cepheus, Cassiopeia high in north, and down through Perseus, Auriga, the horns of Taurus, and the feet of Gemini in NE to ENE. When we look a few degrees east of Elnath, tip of Taurus' northern horn, we're facing outward in the plane of our Milky Way, directly away from the center of our Galaxy. Included within this span of dark mornings is the peak of the Perseid meteor shower, which is expected to offer its richest show before morning twilight on August 13. The sky will be dark and moonless throughout the night of August 12-13, coinciding with New Moon. Adjacent dates should also be good for planning a meteor watch.

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Evening highlights: By far, the brightest "star" in evening twilight is Venus, of mag. –4.3 to –4.6, low in west to west-southwest at dusk. Venus is of increasing interest in the closing months of its evening apparitions, because it's drawing closer to Earth and so appearing to grow larger in size, and begins to move between Earth and Sun and become backlighted, as a crescent. The transition from gibbous phase though half full, to a crescent takes place close to Aug. 14, the date of Venus' greatest elongation, when it reaches its maximum angular distance from the Sun, 46°. This month, watch Venus change from 55 to 39 percent full, while growing from 21" (arcseconds) to 30" in angular diameter.

On August 1 at dusk, find Venus just south of west at dusk, and locate the star Spica in SW, 29° upper left of Venus. Watch Venus approach this star all month, until it passes just 1.5° south (lower left) of the star on Sept. 1. Find another bright zodiacal star, the red supergiant Antares, heart of the Scorpion, 46° east of Spica, or in the south at dusk on Aug. 1, drifting into SSW by Sept. 1.

The Moon in August can be seen on 15 consecutive evenings at dusk, culminating with a deep partial lunar eclipse. On the first evening, Thursday, August 13, just half an hour after sunset, it may be a challenge to catch the 3-percent crescent very low, just north of west, and 28° lower right of Venus. On Aug. 14, you can look for the easier 7-percent crescent a bit later in twilight, 15°-16° lower right of Venus. Saturday, Aug. 15 will present a great photo-op: A 14-percent crescent Moon centered about 3.5°-4° lower right of Venus! Continuing eastward, the 22-percent crescent Moon at dusk on Aug. 16 will appear in WSW 9°-10° left of Venus and 5°-6° lower right of Spica. On Aug. 17, the 31-percent Moon will appear 8°-9° left of Spica. At dusk on Aug. 19, the First Quarter Moon, half full and 90° or one-quarter circle east of the Sun, will sit in SSW, 13°-14° lower right of Antares. On the next evening, Aug. 20, the 60-percent gibbous Moon will stand within 2°-3° lower right of Antares at dusk. At dusk on August 21, the 69-percent Moon appears 10°-11° east of Antares and a few degrees west of the central region of our Milky Way, and on Aug. 22, the 77-percent Moon is east of the galactic center and near the spout of the Teapot, where the Great Sagittarius Star Cloud is located. Definitely not good nights for observing the Milky Way! On Aug. 23, the 85-percent Moon appears near the handle of the Teapot.

For the next several evenings, the Moon makes its way through a fainter region of the zodiac. On Aug. 24, the 91-percent Moon appears in the far eastern part of Sagittarius, nearly 15 degrees east of the 2nd-mag. star in the Teapot's handle. in August's final week, the Moon passes through constellations containing no star brighter than 3rd-mag.: Two nights each in Capricornus and Aquarius, followed by August's last three nights rising soon after sunset, in Pisces.

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When we arrive on Thursday evening, Aug. 27, we'll find the Full Moon rising very shortly before sunset. At 7:33 p.m. PDT, or 10:33 p.m. EDT, the Moon begins to enter the dark, central core of Earth's shadow, called the umbra, and the partial lunar eclipse gets underway. From Palm Springs, California, the Moon at the start of its encounter with Earth's shadow is just 4° above the horizon, 15° south of east. From the Pacific Northwest, the Moon hasn't risen yet, and when it does, the partial eclipse will already be in progress. From the eastern U.S., the Moon will be well above the horizon in late evening, when the eclipse begins.

For the next nearly 100 minutes, more and more of the Moon's disk is immersed in the dark umbral shadow, and quite soon, the circular outline of Earth's shadow edge becomes apparent. When enough of the Moon's disk is immersed in deep shadow, reddish colors typically become noticeable, from sunlight which has been reddened by its passage through Earth's atmosphere, and refracted into the shadow, on its way from the Sun to the Moon.

This lunar eclipse won't be total, but it is a significant partial, with 93 percent of the Moon's diameter covered by the umbra on Thursday evening, Aug. 27, at 9:13 p.m. PDT for western states, or at 12:13 a.m. EDT early on Friday morning for eastern states. All except for a crescent-shaped upper part of the Moon's disk will be covered in deep shadow. The Moon might then resemble a view of Mars with a bright northern polar cap! Where twilight has ended and the Moon is mostly in shadow, the Milky Way should be visible, passing from Perseus, through Cassiopeia, Cepheus, the neck of Cygnus the Swan within the Summer Triangle, down toward the steaming Sagittarius Teapot and the tail of Scorpius. It'll be worth taking a trip to a dark place for this nearly total lunar eclipse, just to experience the full impression of how much darker the sky will get with the reduction in moonlight.

The umbral eclipse ends at 10:52 p.m. PDT Thursday, or equivalently at 1:52 a.m EDT on Friday, as the Moon departs from the dark core of Earth's shadow. The next total lunar eclipse visible from the U.S. will occur on the evening of June 25, 2029. During that event, the Moon will rise at dusk already in total eclipse for observers in the western continental U.S., while those in eastern U.S. will see the entire event.

Prime dates this month for viewing the Milky Way in dark, moonless sky during the first hour after the end of evening twilight are Aug. 4 or 5 through Aug. 14 or 15.

Wishing you clear skies for your choice of these many beautiful events!

Many of the events described above are illustrated on the August 2026 issue of the Abrams Planetarium Sky Calendar. Subscriptions are available for $12 per year, starting anytime, from Abrams Planetarium, Michigan State University, 755 Science Road, East Lansing, MI 48824, or online at https://abramsplanetarium.natsci.msu.edu/sky-calendar

Saturn's Rings 2025-2039 and beyond

You can download a PDF showing and explaining appearance of Saturn's rings over the next 15 years.

Seasonal disappearances of stars - a spring activity

Late March/early April is a good time for students to start keeping a checklist of bright stars seen each evening, within the first hour after sunset. Many bright stars are gathered in the western sky, including the huge Winter Hexagon. Striking changes in the visibility of stars will occur in the next several weeks, as a result of the Earth’s revolution around the Sun. Students can list their sightings of planets, and the Moon, too! Use the Daily Skywatch Log provided to record your observations. To include the greatest number of bright stars, begin this activity by mid-April.

Daily Sky Watch Log Activity

Use this chart to track various stars and planets in the sky.

Daily Sky Watch Log PDF

Planets and bright stars in mid-twilight: monthly charts

Are you organizing a star party for a class or assigning individual sky watching projects? We suggest you plan to begin the sessions during evening twilight, so students can experience the joy of discovering and identifying the brighter stars as they first appear. The sessions should begin no later than one-half hour after sunset, or even earlier if you wish to start with telescopic observations of the Moon or bright planets, and conclude after enough dark-sky time for students to observe the deep sky objects on your list.

If you also schedule a predawn session, you might want to allow enough time to observe a selection of stars and deep sky objects before twilight begins. In that case, start the session at least 1¾ to 2 hours before sunrise, and continue long enough into twilight to watch some of the brighter stars disappear.

My friend and former colleague at Michigan State University, Mr. Robert D. Miller, has kindly created computer programs and provided us with monthly sky charts tracking daily locations of the five naked-eye planets and the 15* stars of first magnitude or brighter (*plus Pollux’s twin, Castor, of mag. +1.6 and only 4.5° away) visible from latitude 40° north. Positions of the stars and planets are plotted each day at the moment the Sun is 9° below the horizon, which we have called “mid-twilight”. Locations of the planets are plotted as a separate dot for each day, with larger dots plotted weekly on the 1st, 8th, 15th, 22nd, and 29th day of the month. Star positions during the course of the month are plotted as continuous tracks, with all stars drifting westward (left to right on the charts) in the course of the month, owing to the Earth’s revolution around the Sun.

For latitude 40° N, the moment of evening mid-twilight during the course of the year ranges from 43 to 53 minutes after sunset, and morning mid-twilight occurs at a similar interval ahead of sunrise For locations south of lat. 40° N, the same stage of twilight occurs closer to sunset and sunrise, for example, 39 to 47 minutes after sunset or before sunrise for lat. 34° N.

*On the set of charts for lat. 34° N, another bright star, Canopus, is sometimes visible very low in the south, bringing the visible total to 16 stars of first magnitude or brighter, but not all are seen simultaneously. For locations farther north, twilights are longer.

Sometimes a star is below the horizon at the start of a month, but might appear above the eastern horizon before month’s end, for example Spica low in ESE in evening mid-twilight in late April. On the evening twilight chart for May, Aldebaran, Sirius, and Betelgeuse are low in the western sky at the start of May, but all sink below the horizon in the course of the month.

It is instructive to view the monthly evening twilight charts in order, to follow the seasonal westward drift of the stars. The outer planets Mars, Jupiter, and Saturn,

moving slowly against the stars, are dragged along with the seasonal motion. Outer planets and zodiacal stars Aldebaran, Pollux and Castor, Regulus, Spica, and Antares follow this sequence from beginning to end of an apparition: (1) First appearance, or heliacal rising, on eastern horizon in morning twilight; (2) progress across morning sky over several months from eastern toward western horizon; (3) opposition, when it appears in western sky at dawn and in eastern sky at dusk; (4) progress across evening sky over several months from eastern toward western horizon; (5) last appearance, or heliacal setting, on western horizon during evening twilight.

Stars well north of the zodiac, Capella, Arcturus, and the Summer Triangle of Vega, Altair, and Deneb begin step (1) of the next apparition before finishing step (5) of a current one, for example, Arcturus, 33° N of Sun on October 29, begins to be seen rising in ENE before dawn several days earlier, and remains visible in the western sky at dusk until several days later. A star well south of the zodiac, for example, Sirius, is never up all night, even at opposition on Dec. 31-Jan. 1, when it’s highest in south in middle of night. For several weeks around the opposite time of year, June 30, Sirius is above the horizon only in the daytime and can’t be seen at any time of night.

Mercury and Venus, planets interior to the Earth’s orbit, can never appear at opposition. When they show on the monthly charts, they’re either in the western sky at dusk or eastern sky at dawn. Venus is visible as an “evening star” or “morning star” for seven to eight months at a time. Its sequence is: (1) Superior conjunction, not visible on far side of Sun; (2) first appearance above western horizon at dusk; (3) greatest elongation about 46° from setting Sun, while appearing half full through a telescope. (4) display of crescent phases, ever thinner but larger in apparent size, while sinking back toward western horizon at dusk; (5) inferior conjunction, nearly between Earth and Sun; (6) first appearance above eastern horizon at dawn, beginning display of crescent phases, ever thicker but smaller in apparent size, while climbing toward (7) greatest elongation, about 46° from rising Sun, appearing half full, followed by (8) gradual descent toward last appearance on eastern horizon at dawn, and finally (9) superior conjunction. The duration of a complete cycle of visibility of Venus, including an evening and a morning appearance between superior conjunctions, is nearly 19.2 months, or 5 complete evening-morning cycles in 8 years.

Venus is especially fascinating to watch with binoculars and telescopes in the closing weeks of an evening apparition through the opening weeks of a morning apparition. Venus then passes close to Earth and appears as a large, backlighted crescent in transition between steps (3) and (7), in the sequence described above. The next two transitions, from Venus half full in evening through crescent phases to half full in morning, take place from mid-August 2026 until early January 2027, and from late March until early August 2028.

Robert C. Victor was Staff Astronomer at Abrams Planetarium, Michigan State University. He is now retired and enjoys promoting sky watching to folks of all ages.

2026 Bright planet and stars mid-twilight charts
Morning	Evening
January	January
February	February
March	March
April	April
May	May
June	June
July	July
August	August
September	September
October	October
November	November
December	December

Planet rising and setting charts

Jeffrey Hunt creates annual graphs of evening setting times and morning rising times of Moon, planets and bright zodiacal stars. Both graphs are calculated for Chicago, but are also fairly accurate everywhere within the 48 contiguous United States.

Saturn begins rising before the start of morning twilight by late May 2026, and Mars does so by late June. Mercury has favorable morning appearances in late July-early August, and again in late November-early December. Jupiter emerges into the morning sky by late August. Venus (green curve) quickly emerges as a "morning star" rising ahead of the Sun in late October. By early November, it rises in a dark sky, before the start of twilight, and in mid-December, rises about four hours ahead of the Sun.

Rising Chart 2026

In May 2026, Venus (green curve) sets in a dark sky, at its longest time interval after sunset. By mid-October, Venus sets at the same time as the Sun and is no longer visible. Jupiter (yellow curve) appears close to Venus on June 9, and sets during ever brighter twilight later on during June. Mercury has favorable evening appearances during mid-February and again in late May to mid-June. Its appearance in October is much less favorable, since it sets in brighter twilight. Aldebaran sinks into bright twilight during May, and Pollux does so in June.

Setting Chart 2026

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