Thursday, Aug. 1 – Milky Way star clusters (all night)
With the moon out of the sky, this week’s extra-dark evenings will be ideal for exploring the countless knots and clumps of stars distributed along the Milky Way, many of which were included in Charles Messier’s list of bright deep sky objects.
Scan around the southern sky with binoculars first, and then take closer looks at them through a backyard telescope at low magnification. Particularly good clusters include Messier 39 and the Cooling Tower Cluster (Messier 29) in Cygnus, the Wild Duck cluster (Messier 11) and Messier 26 in Scutum, the Sagittarius Star Cloud (Messier 24), and Ptolemy’s Cluster (Messier 7) and the Butterfly Cluster (Messier 6) in Scorpius.
Friday, Aug. 2 – crescent moon and Gemini’s Twins (pre-dawn)
Early risers on Friday morning, Aug. 2 can see the pretty crescent moon shining low in the east-northeastern sky. Look a palm’s width to the left (or celestial northeast) of the moon for Gemini’s brightest stars Pollux and Castor.
Skywatchers in more westerly time zones will see the moon a little closer to Pollux, the lower, brighter, and more golden of the two stars. Watch for the bright planets Jupiter and Mars shining well off to the moon’s upper right (or celestial west).
Sunday, Aug. 4 – New Moon
On Sunday, Aug. 4 at 7:13 a.m. EDT, 4:13 a.m. PDT, or 11:13 GMT, the moon will officially reach its new moon phase. (Image credit: Chris Vaughan/Starry Night)
On Sunday, Aug. 4 at 7:13 a.m. EDT, 4:13 a.m. PDT, or 11:13 GMT, the moon will officially reach its new moon phase. At that time our natural satellite will be located in Cancer, 3.9 degrees north of the sun. While new, the moon is traveling in the space between Earth and the sun. Since sunlight can only illuminate the moon’s far side, and the moon is in the same region of the sky as the bright sun, it becomes completely hidden from view from anywhere on Earth for about a day (unless there’s a solar eclipse). In the evenings after the new moon phase, Earth’s celestial night light will shine as a crescent in the western evening sky.
Monday, Aug. 5 – crescent moon joins Venus (after sunset)
Above the western horizon on Monday, Aug. 5, the very slender crescent of the young moon will appear close to the brilliant planet Venus. After the sun has completely set, look with your unaided eyes or use binoculars (orange circle) to spot the duo before they set about an hour after sunset.
Skywatchers in different time zones will see the moon and Venus arranged in various ways because the moon moves east by its own diameter every hour. In Europe, the moon will sit off to Venus’ right. In the Americas, Venus will be located just below (or celestial south of) the moon. Sharp eyes might also spot Leo’s brightest star Regulus just below them and Mercury off to their lower left.
Tuesday, Aug. 6 – bright clusters for Binoculars (evening)
Tuesday night, Aug. 6 will be a fine time to grab your binoculars and view three large open star clusters that occupy the southern sky between the bright stars Altair and Cebalrai. The Summer Beehive Cluster aka IC 4665 is a loose collection of stars centered just a finger’s width above (or 1 degree northeast of) Cebalrai. Its white stars, which are spread across an area more than twice the diameter of the moon, host several reddish intruders. Next, aim your binoculars midway between Cebalrai and Altair and look for two patches of stars sharing the same binoculars field of view (orange circle). The smaller, but brighter Tweedledum Cluster (or NGC 6633) is centered several finger widths to the upper right (or celestial northwest) of the larger, but fainter Graff’s Cluster (or IC 4756). It’s fun to count each cluster’s stars and note the various star colors and the patterns the stars are arranged in.
Wednesday, Aug. 7 – double shadows cross Jupiter
From time to time, observers with good-quality telescopes can watch the black shadows of the Galilean moons travel across Jupiter’s disk. On Wednesday morning, Aug. 7, for observers in most of the Americas, two shadows will cross the southern hemisphere of Jupiter simultaneously.
At 2:55 a.m. EDT (or 06:55 GMT), Europa’s shadow will join the slightly larger shadow of Io that began its own crossing several minutes earlier. As the shadows cross the planet, Io and Europa themselves will approach and then move onto Jupiter. Io’s shadow will complete its passage towards 4 a.m. EDT (08:00 GMT), leaving Europa’s shadow to journey on alone until 5:20 a.m. (or 09:20 GMT).
Thursday, Aug. 8 – the teapot tilts west (evening)
With the crescent moon setting early on Thursday, Aug. 8, conditions will be ideal for viewing one of the best asterisms in the sky. The stars of Sagittarius, the Archer, form an obvious Teapot shape with a flat bottom formed by the stars Ascella on the left (east) and Kaus Australis on the right (west), a pointed spout on the right (west) marked by the star Alnasl, and a pointed lid marked by the star Kaus Borealis.
The stars Nunki and Tau Sagittarii form a handle on the left-hand (eastern) side. The name Kaus used for the bent, up-down line of three stars — Borealis (north), Meridianalis (center), and Australis (south) — refers to the archer’s bow.
The center of our galaxy is only a palm’s width to the right of Alnasl. When the asterism reaches its maximum height above the southern horizon, around 10:30 p.m. local time, it will be tilted west — the Milky Way evoking steam rising from its spout. The dwarf planet Ceres will be traveling through the teapot this summer.
Friday, Aug. 9 – crescent moon approaches Spica (evening)
As darkness falls on Friday evening, Aug. 9, look in the lower part of the southwestern sky for the pretty, waxing crescent moon shining to the lower right of Virgo’s brightest star, Spica. In the Americas, the duo will be close enough to share the view in binoculars (orange circle).
Hours later, the moon’s eastern orbital motion will cause it to pass in front of (or occult) Spica. For observers in parts of northeastern Europe, the western half of Russia, and most of Asia, the event will occur in daylight on Saturday, Aug. 10. Folks across northern Indonesia, southern Japan, and western Micronesia will see the occultation in a dark sky.
Sunday, Aug. 11 — Perseids meteor shower peak (overnight)
The spectacular Perseids meteor shower, which runs between July 17 and Aug. 24 every year, will peak after midnight in the Americas on Sunday night, Aug. 11. With a 44%-illuminated waxing crescent moon setting in the late evening, the best time for seeing Perseids meteors in North America will be between 11 p.m. on Sunday and dawn on Monday morning, while the shower’s radiant in Perseus is high in the northeastern sky.
This is the most popular shower of the year, delivering as many as 100 meteors per hour at the peak. Derived from debris dropped by Comet Swift-Tuttle, many Perseids are extremely bright and leave persistent trails. To see the most meteors during any meteor shower, find a safe, dark location with plenty of open sky, get comfortable, and just look up.
Monday, Aug. 12 – First quarter moon
The moon will complete the first quarter of its journey around Earth on Monday, Aug. 12 at 11:19 a.m. EDT, 8:19 a.m. PDT, or 15:19 GMT. At that time, its 90-degree angle away from the sun will cause us to see the moon half-illuminated — on its eastern side.
At first quarter, the moon always rises around mid-day and sets around midnight, so it is also visible in the afternoon daytime sky. The evenings surrounding first quarter are the best ones for seeing the lunar terrain when it is dramatically lit by low-angled sunlight, especially along the terminator, the pole-to-pole boundary that separates the lit and dark hemispheres.
Tuesday, Aug. 13 – moon crosses the scorpion’s heart (evening)
On Tuesday, Aug. 13 the waxing, gibbous moon will rise in mid-afternoon. As the sky darkens after sunset, Antares, the bright, reddish, supergiant star in the heart of Scorpius, will appear just to the moon’s upper left, close enough for the duo to share the view in binoculars (orange circle).
Due to the moon’s continuous eastward orbital motion across the stars, it will pass closely below Antares for those viewing in westerly time zones. Observers in the South Pacific Ocean region, including the Galapagos Islands, can watch the moon occult Antares after midnight.
Wednesday, Aug. 14 — Mars meets Jupiter (pre-dawn)
On the mornings surrounding Wednesday, Aug. 14, the orbital motion of the red planet Mars will carry it very closely past brilliant, white Jupiter. The pair of planets will clear the eastern rooftops after about 2 a.m. local time and then remain visible in the southeast until sunrise.
Mars will approach Jupiter from the upper right (or celestial west) before Wednesday and then widen its gap to Jupiter’s lower left from Thursday onward. The two planets will share the view in binoculars (orange circle) from Aug. 3 to Aug. 25 and will be cozy enough for telescope viewing as a pair from Sunday through Saturday.
Friday, Aug. 16 – catch the colors of stars (all night)
Bright stars can still be enjoyed on a moonlit night. Stars shine with a color that is controlled by their photospheric temperature, and this is captured in their spectral classification.
The three bright stars of the eastern sky Summer Triangle asterism, named Deneb, Vega, and Altair, are A-class stars that appear blue-white to the eye. They have temperatures in the range of 7,500 to 10,000 Kelvin. Arcturus, which is located in the western evening sky, is an orange, K-class giant star with a temperature of only 4,300 K. Reddish Antares, the heart of Scorpius, is an old M-class star with a low surface temperature of 3,500 K.
After midnight local time, look for very bright, yellowish Capella rising in the northeast. You can estimate the temperatures of fainter stars by comparing their color to these bright reference stars.
Monday, Aug. 19 – full Sturgeon Moon
The full moon of August will occur on Monday, Aug. 19 at 2:26 p.m. EDT, 11:26 a.m. PDT, or 18:26 GMT. In the Americas, the moon will look almost full on Sunday night and then ever-so-slightly less than full when it rises around 8 p.m. local time on Monday. It will hang unusually low in the sky because it will be traveling about 4 degrees below the already low summertime ecliptic.
The August full moon, colloquially called the “Sturgeon Moon”, “Red Moon”, “Green Corn Moon”, and “Grain Moon”, always shines among or near the stars of Aquarius or Capricornus. The indigenous Anishinaabe people of the Great Lakes region call it Manoominike-giizis, the Wild Rice Moon, or Miine Giizis, the Blueberry Moon. The Cree Nation of central USA and Canada calls the August full moon Ohpahowipîsim, the Flying Up Moon. The Haudenosaunee (Iroquois) of Eastern North America call it Seskéha, the Freshness Moon.
Tuesday, Aug. 20 – bright moon shines with Saturn (all night)
After the very bright, almost full moon clears the treetops in the east around 9:30 p.m. local time on Tuesday, Aug. 20, it will be shining very closely below (or celestial south of) the bright, yellowish dot of Saturn.
Throughout the night, the pair will cross the sky together. Meanwhile, the moon’s eastward orbital motion and the diurnal rotation of the sky will pull the moon farther from Saturn and rotate the ringed planet below the moon. Watch for them low in the southwestern sky before sunrise on Wednesday morning. Observers in a zone across northern South America and across the Atlantic Ocean to northwestern Africa and western Europe can watch the moon occult Saturn on Tuesday around 04:00 GMT.
Friday, Aug. 23 – small constellations on high (evening)
On late-August evenings, four small constellations sit high in the southeastern sky below the very bright star Vega. The easiest one to see is Delphinus, the Dolphin, which is composed of four medium-bright stars forming a small elongated diamond connected to a star extending to the lower right (or celestial southwest).
Equuleus, the Little Horse is positioned about a fist’s diameter below Delphinus. Diminutive Equuleus is the second to last constellation by size, after Crux, the Southern Cross. Sitting a generous fist’s width above Delphinus is the next smallest constellation by area, Sagitta, the Arrow. And sweeping a palm’s width higher will bring you to the stars of Vulpecula, the Fox.
Except for the slightly larger fox, each of these small constellations will fit within the field of view of binoculars. The Milky Way passes through Sagitta and Vulpecula, populating them with a variety of deep sky objects. The sky between those two constellations hosts a dark dust lane.
Saturday, Aug. 24 – double stars in Lyra’s parallelogram (all night)
Each corner of Lyra’s parallelogram is marked by a double star. Zeta Lyrae (ζ Lyr), the corner closest to the very bright star Vega, can be split with binoculars (orange circle).
Both components are white, with one star slightly brighter than the other. Each of these stars also has a partner that is too close together to split visually. Moving clockwise, the southwest corner star is Sheliak, the brightest of a tight little grouping of stars visible in a telescope.
Sheliak itself has a close-in, dim companion in an eclipsing binary system with a 13-day period. The hot, blue giant star Sulafat sits at the farthest corner from Vega. 620 light-years-distant Sulafat is much larger than Vega — an old star on its way to becoming an orange giant many years from now. Add the slightly dimmer stars Lambda Lyrae and HD 176051 to its south and west, respectively to form a naked-eye triple. Delta Lyrae (δ Lyr) marks the northeast corner of the parallelogram.
Sharp eyes and binoculars will easily split the double into one blue and one red star. The blue star is one hundred light-years farther away than the red one; they just happen to appear close together along the same line of sight.
Sunday, Aug. 25 – half-moon near the Pleiades (overnight)
Once the half-illuminated moon has cleared the eastern rooftops towards midnight on Sunday, Aug. 25, it will spend the rest of the night crossing the sky with nearby Uranus and the bright little Pleiades star cluster, aka the Seven Sisters and Messier 45.
Use binoculars (orange circle) to easily see the stars of the cluster arrayed to the upper right of the moon. The “sisters” will be farther from the moon for observers viewing them later or in more westerly time zones. The distant planet Uranus, which is visible in binoculars, will spend this year about a palm’s width to the right (or celestial SSW) of the Pleiades.
Monday, Aug. 26 – Third Quarter Moon
The moon will complete three-quarters of its orbit around Earth, measured from the previous new moon, on Monday, Aug. 26 at 5:26 a.m. EDT, 2:26 a.m. PDT, or 09:26 GMT.
At its third (or last) quarter phase, the moon appears half-illuminated, on its western, sunward side. It rises around midnight local time and then remains visible until it sets in the western daytime sky in the early afternoon. Third quarter moons are positioned ahead of the Earth in our trip around the Sun. About 3.5 hours later, Earth will occupy that same location in space. The week of dark, moonless evening skies that follow this phase is the best one for observing deep sky targets.
Tuesday, Aug. 27 – crescent Moon above Mars and Jupiter (pre-dawn)
From the wee hours until dawn on Tuesday morning, Aug. 27, the pretty, waning crescent moon will shine above the planets Jupiter and Mars in the eastern sky, setting up a nice widefield photo opportunity. Brilliant Jupiter will be unmistakable — almost close enough to the moon for them to share the view in binoculars.
The reddish, medium-bright dot of Mars will be positioned a palm’s width to the lower left (or 6 degrees to the celestial east) of Jupiter. Watch for the bright, reddish star Aldebaran, the angry eye star of Taurus, the Bull, sparkling off to the right of the group.
Thursday, Aug. 29 – watch Algol brighten
The star Algol (or Beta Persei) in the constellation of Perseus is among the most easy-to-monitor variable stars. During a ten-hour period that repeats every 2 days, 20 hours, and 49 minutes, Algol dims noticeably and then re-brightens when a companion star with an orbit nearly edge-on to Earth crosses behind the much brighter main star, reducing the total light output we perceive.
Algol normally shines at magnitude 2.1, similar to the nearby star Almach in Andromeda. But while dimmed to minimum brightness, Algol’s magnitude of 3.4 is almost the same as the star Rho Persei (ρ Per), which shines just two finger widths to Algol’s lower right (or 2.25 degrees to the celestial south).
For observers in the eastern half of North America, fully dimmed Algol will sit in the lower part of the northeastern sky on Thursday morning, Aug. 29 at 12:02 a.m. EDT or 04:02 GMT. Five hours later the star will shine at full intensity from a perch nearly overhead in the eastern sky. Observers in more westerly time zones will see most of the brightening process.
Friday, Aug. 30 – the crescent moon aligns with Gemini’s Twins (pre-dawn)
On Friday morning, Aug. 30, early risers can see the waning crescent moon forming a line below Gemini’s two brightest stars in the eastern sky. Pollux, the lower star is brighter and more yellowish in color than its “twin”, the double star Castor, above it. Even as the sky begins to brighten ahead of sunrise, the bright stars of winter will sparkle off to the right of Gemini and the moon.
Read more at: https://www.space.com/16149-night-sky.html