Sky Data

Tuesday May first, sunrise is at 5:54 a.m. That evening the Sun located in the constellation Aries sets at 7:52.

On May 15th sunrise is at 5:38 and sunset occurs at 8:06 p.m.

The last day of the month the Sun is in Taurus, rising at 5:27 a.m. and setting at 8:20 that evening. During May the length of time the Sun is above the horizon each day increases by 54 minutes. The altitude of the Sun at solar noon, its highest daily elevation, ascends during May from 65 degrees of arc to 71 degrees.

Average overnight temperatures in Central Park rise from 49 degrees Fahrenheit on the first to 59 degrees on the last day of May.

Principal Phases of the Moon are:

Sky Cast

During May Mercury is too close to the Sun’s direction for convenient observations.

On the other hand Venus is a brilliant sight in the western evening sky during most of the month. At the start of May it has visual magnitude -4.5, and angular separation from the Sun of 39 degrees of arc. Separation decreases rapidly from night to night. As the month progresses Venus will be lower in the west as it approaches the Sun’s direction. On June 5 it will be between Earth and Sun and observers using proper filters may see Venus appear as a black dot crossing the solar disk. This transit event has been long anticipated and a similar passage will not occur until December of the year 2117. Extreme care must be used during any direct solar observation to prevent blindness. Only those experienced in the use of high grade solar filters, or capable of safely projecting the Sun’s image onto a surface to view the transit indirectly, should make the attempt. Otherwise, it is advised to follow the event via internet or television.

During May, as Venus appears to move in the Sun’s direction, a telescope shows the Venusian crescent lengthening as the planet’s distance from us decreases from 41 million to 27 million miles. Venus’ apparent size thereby increases from 38 to 57 seconds of arc by the end of May.

Watching these changes can give a sense of that planet’s orbital motion. The apparent drop of Venus and its lengthening crescent are manifestations of harmony between gravity pulling Venus toward the Sun and orbital motion ensuring that planet maintains a safe solar distance. Orbital motion in our direction is evident as we see Venus appearing increasingly larger this month. On June 5th when that planet crosses in front of the solar disk, its distance from Earth will be at a minimum. In following weeks Venus will move away from the Sun’s direction and become visible in our pre-dawn skies.

Mars is in Leo during May, beginning the month near the waxing Moon, six degrees east of first magnitude Regulus. On May first the Red Planet is 87 million miles from earth with a visual magnitude of 0.0. Mars is in Leo throughout May and at month’s end will be 109 million miles from Earth, with slightly diminished brightness and a disk diameter of just eight arcseconds, too small to reveal surface details through a small telescope.

Jupiter sets at 8:31 p.m. at the start of May, 39 minutes after sunset. It will be hidden in the glow of evening twilight through this month, and on May 13 passes less than one degree of arc south of the solar disk. At the end of May the big planet rises 39 minutes before sunrise.

Saturn is in Virgo this month near first magnitude Spica, a white star that contrasts with Saturn’s slightly yellowish hue. The planet with the solar system’s most magnificent set of rings shines at magnitude 0.31, slightly brighter than Spica.

If you have never observed sixth magnitude Uranus or eighth magnitude Neptune, you’ll need binoculars or a telescope and look for them from a dark sky site. During May both planets are visible during several hours before dawn, with Uranus about 13 degrees south of second magnitude Algenib in Pegasus. Neptune is 34 degrees west of Uranus, in Aquarius about 10 degrees south of that constellation’s “Water Jar” asterism

The night of May fourth, the Moon is in Virgo forming a small triangle with Saturn and Spica.

Traditional names for May’s Full Moon, located in the constellation Libra on Saturday the fifth, include Full Flower Moon and Full Corn Planting Moon.

Our view into intergalactic space is blocked over a large swath of sky by vast clouds of dust permeating the Galaxy’s disk, a region highlighted by the Band of the Milky Way. However dust interference is at a minimum in a zone around the Galaxy’s poles, one of which is near the meridian high in our southern sky during spring evenings. As a result, under dark skies some members of the Virgo Supercluster may be seen even with binoculars, in Virgo and neighboring Leo. Edwin Hubble called this part of the sky the “Realm of the Nebulae”. Thanks in large part to his research the word nebulae, meaning mist in Latin, is no longer applied to what are now called galaxies, and is reserved for relatively small clouds of dust and gas within the spiral galaxies.

During early evening of Tuesday May 22 in fading twilight, a very thin crescent Moon is five degrees to the lower left of Venus. At 9:15 p.m. the Moon is five degrees above our west-northwest horizon.

On Monday May 28 the first quarter Moon is near Mars in Leo.

Sky Lore

When the north pole of the Milky Way is near the meridian the Galactic equator nearly coincides with our horizon. Star light and glowing gas in the Band of the Milky Way then encircles us with a faint undulating glow extending about ten degrees above the horizon. To view this phenomenon you must be at a very dark site with an unobstructed horizon.

Cultures around the world tell many stories about the Milky Way. The name comes from a Greek legend about Hera goddess Queen of Olympus nursing the infant Hercules while she was asleep. Startled upon wakening, she pushed him aside with a resulting spray of milk that rose to create the Milky Way’s Band.

Khoisan people of Africa’s Kalahari have a legend about a time long ago, before stars had existed, when a young girl threw glowing embers from a fire into the sky to guide her way on a night trek to visit distant villages.

A Cherokee tale tells of a dog running off with a sack of cornmeal, spilling it along the way thereby forming stars of the Milky Way.

Oriental stories describe the Milky Way as the celestial barrier keeping a beautiful princess separated from her lover, a humble shepherd.

Under dark skies, binoculars and small telescopes can show a number of galaxies in the Virgo Supercluster, centered about 60 million light years from us. However to detect even a few galaxies in more remote superclusters, telescopes at least ten inches in diameter are usually needed. Several impressive galaxy clusters considerably more distant than those in Virgo are now in our evening sky.

The Coma Supercluster, 300 million light years from us, extends over a spherical region about 20 million light years in diameter and containing several thousand individual galaxies each with many billions of stars. This vast assembly is moving away from us at 4,100 miles per second and is within boundaries of the faint constellation Coma Berenices, just south of the Big Dipper’s handle.

Observations showed galaxies in the Coma Supercluster orbiting their mutual center much faster than expected. These extraordinary speeds revealed the presence of a mysterious essence called Dark Matter that permeates areas of galaxy clusters and induces their members to have such rapid orbital motion. It is believed Dark Matter occupies about 26% of the universe, with the visible galaxies of stars accounting for just four percent of everything now known to exist, with the remainder consisting of Dark Energy.

In constellation lore Coma Berenices represents long beautiful hair clipped and offered by Queen Berenices of Egypt as a sacrifice to the gods to insure her pharaoh husband’s safe return from battle.

Further east, in Corona Borealis several members of the Corona Supercluster of galaxies, may be glimpsed in moderate sized telescopes at a distance of one billion light years from the Milky Way Galaxy. This huge group with thousands of members was discovered by Edwin Hubble during the 1930’s. Speeds of recession from us were measured by his colleague at Mt. Wilson Observatory Milton Humason and are currently listed at about 13,300 miles per second. These astronomers provided vital evidence of the link between velocity and distance of galaxies, the basis of Hubble’s law that led to development of the Big Bang concept.

The constellation Corona Borealis features a small but attractive semi-circle of stars the brightest of which is second magnitude Alphecca. Corona has mythological association with the “Crown of Ariadne”, presented when she became queen of Naxos after being taken there by Theseus, whom she had helped escape from the labyrinth on Crete.

Sky Data

Sunday April 1st, sunrise is at 6:39 a.m. Eastern Daylight Time. That evening the sun, located in the constellation Pisces, sets at 7:21 p.m.

On Sunday April 15th sunrise is at 6:16 a.m., and sunset occurs that day at 7:36 p.m.

The last day of the month, Monday April 30th, the sun is in Aries, rising at 5:55 a.m. and setting at 7:51 that evening. During April the length of time the sun is above the horizon each day increases by one hour 14 minutes. The altitude of the sun at noon, its maximum daily elevation, ascends during April from 54 degrees of arc on the first to 64 degrees on the 30th.

During this month average overnight temperatures recorded in Central Park near Belvedere Castle rise from 37 degrees Fahrenheit on the first to 46 degrees on the 30th.

Principal Phases of the Moon are:

Sky Cast

On Sunday April 1st, Mercury rises in the predawn sky at 5:55 a.m., just 33 minutes before the sun. The following evening Venus is a magnificent sight in the western sky, above bright Jupiter. Mars is also above the horizon at the end of civil twilight, high in the southeast. Saturn rises at 8:22 p.m. That night the waxing gibbous moon is in between Mars and the bright zero magnitude star Procyon in Canis Minor.

During evenings from April first through Wednesday the 4th, Venus passes the tiny dipper shaped asterism in the midst of the Pleiades open star cluster in Taurus. Binoculars or a low power telescope will show these beautiful objects as Venus nightly moves eastward through the zodiac. Its passages relative to “fixed stars” such as the Pleiades reinforce our understanding of why planets were known as “wandering stars.” During April Venus’ crescent phase narrows and appears to lengthen as the planet’s distance from Earth diminishes preceding its much anticipated June conjunction and transit of the Sun’s disk.

Monday and Tuesday April 2nd and 3rd, the waxing gibbous moon may be seen eight degrees from Regulus, brightest star in the constellation Leo.

By the night of Friday April 6th the moon will have moved to a position just west of Saturn and first magnitude star Spica in Virgo.

During the early morning of Tuesday April 10th the waning gibbous moon is four degrees north of first magnitude red supergiant Antares in Scorpius. The next night the moon is not far from the direction of the supermassive black hole 26,000 light years from us at the center of the Milky Way Galaxy.

April 14th Saturn is in opposition, rising at sunset and remaining in the sky through the night.

Wednesday April 18th Mercury is at its greatest western elongation, in the early morning sky 27 degrees of arc west of the sun measured along the ecliptic. However it is only three degrees above the eastern horizon when civil twilight begins on the morning of the 18th. Locating Mercury this month is as usual a difficult task.

During evening twilight on April 22nd a thin crescent moon is low in the western sky, three degrees above Jupiter. On the evenings of the 24th and 25th, the moon is within 12 degrees of Venus.

The night of Saturday April 28th the moon is seven degrees of arc southwest of the Beehive open star cluster in the constellation of the Crab. The cluster, also known as the Praesepe (Latin for “manger”) and as Messier 44, extends across an area of the sky about four times that covered by the moon’s disk. At a distance of about 800 light years this represents an actual diameter of 20 light years. Although visible to unaided eyes on very clear dark nights, looking like a “little mist”, binoculars easily show this cluster. The Beehive is estimated to be 580 light years from the Solar System, with an age of about 800 million years. Look a half fist length above the moon on April 28th to view the celestial Beehive.

On the last evening of April a waxing gibbous moon is near Mars, just south of both the ecliptic and Regulus, brightest star in the constellation Leo.

Sky Lore

During April the Big Dipper and Leo anchor center stage in the early evening sky, with the Dipper high in the north near the zenith. Although having fainter stars than many we saw on winter evenings, the Big Dipper joins Regulus in Leo, Arcturus in Bootes, and Spica in Virgo, marking special places in our celestial view this season. Seven Big Dipper stars comprise a significant part of Ursa Major, the Great Bear and it is an unmistakable pattern. Its delicate esthetic is remarkable and unforgettable.

The Big Dipper contains the fine stellar pair Mizar and Alcor, marking a bend in the asterism’s handle. They and four other Dipper stars belong to the Ursa Major moving cluster, traveling together through the Milky Way Galaxy. Known in sky lore as the “horse and rider” Mizar and Alcor are separated by 12 arcminutes, about one-third the diameter of the moon’s disk. The respective distances from Earth of Mizar and Alcor are 78 and 81 light years. Observers with excellent vision may see Alcor, at visual magnitude 4, and Mizar at magnitude 2.2 as separate points of light. If vision is not quite 20/20, binoculars show the pair’s separation. Focusing our attention on Mizar, using a telescope with magnification of at least 50 times, this star can be seen as double, its components separated by 14 arcseconds (equivalent to about 500 times the distance from Earth to the Sun). Although an orbital connection between Alcor and Mizar may exist, components of Mizar are definitely linked by gravity and revolve around their common center of mass over a period of more than 5,000 years. Furthermore, each is a very close double star, with separations revealed by spectroscopic analysis.

When you have located the Big Dipper, use it as a guide to other features of April’s sky. For example, with a bit of imagination we can think of the Dipper’s bowl filled with water that suddenly spills down onto Leo, the celestial Lion. Regulus is Leo’s brightest star and it is 77 light years from us. It is the first magnitude star closest to the ecliptic, the sun’s apparent annual path through our sky. Regulus means “little king”, a name said to have been provided by Copernicus.

Referring again to the Big Dipper, we can trace a curve along its handle to the star Alkaid. Extend an imagined arc about 30 degrees (three fist lengths) to the zero magnitude star Arcturus in the constellation Bootes, the herdsman. In our night sky Arcturus is second only in stellar brilliance to Sirius and is a highlight of springtime nights. Arcturus is 37 light years from us and has a slightly orange color. It has a relatively fast southward motion quite different from other stars in the neighborhood of the Sun and is described as a “high velocity” star. Arcturus may have been a member of a small galaxy that collided with and was absorbed by the Milky Way Galaxy about five billion years ago.

Continuing the imaginary curve southward past Arcturus brings our attention to first magnitude Spica, brightest star in Virgo. It and Arcturus were known in Arabian mythology as representing posts supporting the canopy of the sky.

Sky Data

Thursday March first, sunrise is at 6:29 a.m. Eastern Standard Time. That evening the sun, located in the constellation Aquarius, sets at 5:48 p.m.

Civil twilight occurs when the sun is less than six degrees of arc below the horizon. It precedes sunrise and follows sunset by about a half hour. During darker segments of this period the moon, bright planets, and several of the brightest stars might be seen.

Thursday March 15th sunrise is at 7:07 a.m. (Eastern Daylight Time) and sunset occurs that day at 7:03 p.m.

On the last day of the month, Saturday March 31st, the sun is in Pisces, rising at 6:40 a.m. and setting at 7:20 that evening. During March the length of time the sun is above the horizon each day increases by one hour 21 minutes. The altitude of the sun at noon, its maximum daily elevation, ascends during March from 42 degrees of arc on the first to 54 degrees on the 31st.

During this month average overnight temperatures recorded in Central Park rise from 29 degrees Fahrenheit on the first to 37 degrees on the last day of March.

Principal Phases of the Moon are:

Sky Cast

During March, in addition to start of Daylight Saving Time and the beginning of the northern hemisphere’s spring season, there is a full slate of planetary activity. Venus, Jupiter, Mars, Saturn, plus elusive Mercury and faint Uranus are on the evening sky stage.

All month, brilliant Venus and Jupiter form a striking pair in the western sky for several hours after sunset. At the start of March they are easily seen in the same field of view after twilight fades.

During March, Mars is at its brightest for 2012. Early this month the red planet is at opposition, rising at sunset and remaining in the sky all night.

On March first, Mercury sets an hour and 28 minutes after the sun. The first weeks of this month provide opportunities for locating Mercury in the evening sky. Saturn rises at 9:33 p.m. on March first, other bright planets are all above the horizon at sunset.

Venus and Jupiter are spectacular visual treats throughout March. On the first of the month they are just 12 degrees of arc apart. They appear to approach each other until Tuesday the 13th, when the two are in conjunction. The brilliant planets then slowly separate, and by month’s end are 15 degrees apart in the western sky.

Mars is at opposition Saturday March third. It is then directly across the sky from the sun, and rises at about sunset. The red planet remains above the horizon all that night, shining at magnitude -1.2. Its distance from Earth then is about 62,658,700 miles, and the planet presents an apparent disk diameter of 14 seconds of arc. This small size makes viewing Martian surface details a challenging task, even with moderately sized telescopes. By comparison, during the great August 26, 2003 opposition, the disk of Mars appeared 21arcseconds in diameter.

Wednesday and Thursday, March 7 and 8 the moon appears near Mars in the constellation Leo.

On March 8 the Full “Worm” Moon is located in Virgo, 14 degrees southeast of Mars. Worms apparently become active this month. Other traditional names for March’s full moon include Full Crow Moon and Full Crust Moon, associations with late winter appearances of these loud birds and ice crusts on partially melted, then refrozen snow.

Saturday March 10th, the waning gibbous moon forms a nearly equilateral triangle with Saturn and first magnitude star Spica in Virgo. These objects are then seven degrees of arc from each other. The span is approximately equal to the apparent width of three fingers seen at arm’s length.

Daylight Saving Time begins during the early morning of Sunday March 11th when at 2 a.m. we set our clocks forward one hour.

Venus and Jupiter are in conjunction Tuesday March 13, with a separation of three degrees of arc, about six times the apparent diameter of the full moon’s disk.

On the night of March 14, the last quarter moon may be seen near the first magnitude red supergiant star Antares in the constellation Scorpius.

The northern hemisphere’s spring season begins at 1:14 a.m. EDT Tuesday March 20th when the sun is directly over a point on the equator at longitude103° 05' east, in Sumatra Indonesia, about 104 miles south-southwest of Singapore.

During early evenings of Sunday, Monday, and Tuesday March 25th through 27th, the waxing crescent moon is near Venus and Jupiter in the western sky. Such configurations are among the most spectacular and beautiful celestial sights to unaided eyes. Treat yourself to the breathtaking experience of seeing these configurations. Add to the pleasure by asking friends to sky watch with you.

On the night of the 26th, the moon is just three degrees of arc from Venus, and seven degrees from the Pleiades open star cluster. Sharp eyed observers may be able to discern six or seven stars in this famous cluster, including its brightest member, third magnitude Alcyone. The cluster’s brightest stars form a pattern that resembles a tiny dipper, considerably smaller than the Little Dipper in Ursa Major.

The First Quarter moon is in the constellation Gemini during the night of March 30th. It is among stars marking feet of mythical celestial twins Castor and Pollux.

During the early morning of March 31st Mars sets at 5:39 a.m. and Mercury rises at 5:58. That evening Saturn rises at 8:26 p.m., Jupiter sets at 9:57, and Venus disappears beneath the west-northwest horizon at 11:24.

Sky Lore

March is the time of year when we prepare to bid temporary farewell to stars in and around Orion. By month’s end the sun’s progression through the zodiac begins to overwhelm light of stars typical of winter evenings. As springtime advances we say good-by to objects such as the Pleiades and Belt stars of Orion, and must wait until early mornings of August to revisit them.

Before that happens, we might turn a telescope to features such as the Great Nebula in Orion, located just south of the Hunter’s Belt, and resembling a “fuzzy star” to unaided eyes. And perhaps we might turn our telescope to the second magnitude star Castor, marking the head of the more northerly of Gemini’s twin stars. Nearby Pollux is the other star-brother-hero of ancient Hellenic mythology. Although seen as a single object to our unaided eyes, Castor is actually a multiple system containing three mutually orbiting sets of double stars, a total of six, whose blended light forms naked eye Castor. A small telescope reveals the three major components, designated Castor A, B, and C. The double nature of each is only revealed with the help of spectroscopic analysis.

Castor was said to have been mortal, while his brother Pollux was the immortal child of Leda and Zeus. Both were Argonauts who sailed in quest of the Golden Fleece and were considered patrons of navigators and warriors.