Mars Visits the Beehive Star Cluster

Considering the thousands of stars in the sky, it is surprisingly rare to see a star in the same telescope field as one of the planets. The reason is that planets generally require a lot of magnification, and this severely limits the field of view of a telescope when looking at a planet.

On Thursday morning, August 20, just before dawn, the planet Mars will pose in front of a swarm of stellar bees, the Beehive Cluster (Messier 44) in the constellation Cancer. Credit: Starry Night software.

On the morning of Thursday, August 20, we will get a special treat, when the planet Mars appears in the midst of hundreds of stars: the open star cluster known as the Beehive, Praesepe, or Messier 44.

This star cluster is called “the Beehive” because of its resemblance to a swarm of bees. It is also known as “Praesepe,” which is Latin for “manger,” because of its position between the stars Asellus Borealis and Asellus Australis, the northern and southern donkeys. Finally, it is number 44 in Charles Messier’s famous catalog of deep sky objects.

Located 590 light years from the sun, the Beehive is one of the nearest and brightest star clusters in the sky. Its several hundred stars are concentrated in a volume 16 light years across, and it actually outshines all of the individual stars in its constellation, Cancer.

You may be wondering where Mars is in the sky, because we haven’t heard much about it lately. That is because it has been on the far side of the sun in recent months, and impossible to see. It is only now emerging from the sun’s glare and reappearing in the morning sky, just before dawn. Look for it around 5 a.m. this week low in the northeastern sky, and be sure to use binoculars if you want to see the Beehive behind it.

Even in the smallest telescope, Mars should make a pretty picture lying in front of the many stars of the Beehive. But be sure to catch it Thursday or Friday morning, because by Saturday it will have passed the Beehive.

Mars itself will be a disappointing sight, as it is still very far away from Earth, 2.5 astronomical units distant and less than 4 arc seconds in diameter. It won’t be large enough to show much detail until mid-March next year, heading towards its most favorable opposition in over a decade 

Most Amazing Meteor Shower Of The Year Peaks Tonight

If you spend half an hour under a dark sky this week, you are very likely to see a meteor. Thursday morning at 2 a.m. EDT, the Perseid meteor shower reaches its peak. Remember that the date changes at midnight, so we’re talking about Wednesday night.

On Thursday night, August 13, at 2 a.m. EDT, the Perseid meteor shower reaches its peak. Credit: Starry Night software.

Meteors, popularly called “shooting stars,” are caused by small pieces of interplanetary matter known as meteoroids. These are smaller than asteroids, ranging in size from 40 inches (1 metre) in size down to objects the size of a grain of sand. These are heated to fluorescence when they encounter the Earth’s atmosphere, and observers on the ground see a rapidly moving bright point of light.

If the meteor is large enough, it may leave a train of glowing particles in its wake, which usually fades within a few seconds. Meteors do not have tails; this is because of confusion with comets, which move far more slowly and do have tails. A comet is visible for weeks or months, whereas a meteor is gone in a second or two.

Meteoroids are distributed throughout the Solar System, so it’s possible to see a meteor on any night in the year; these are called “sporadic meteors.” But some areas have a greater concentration of meteoroids, usually moving in the same orbit as a comet or asteroid which has gradually lost material along its orbit. The Perseids are associated with Comet Swift-Tuttle, which was discovered in 1862 and last observed in 1992. It will next be close to Earth in 2126.

When the Earth passes through a concentration of meteoroids, we get a greater number of meteors, what we call a “meteor shower.” These meteors may appear anywhere in the sky, but if you trace their paths backwards, they will all appear to come from a point in the sky known as the “radiant” of the shower.

These showers are usually named for the constellation in which the radiants lie, so the shower this week is called “the Perseids” after the constellation Perseus, which lies between Cassiopeia and the bright star Capella.

If you look straight at the radiant of a meteor shower, you will see the meteors appearing to come towards you and pass by on either side. Because of perspective, the meteors will tend to be short in length and brief in time. If you look well off to the side of the radiant, the meteors you’ll see will be longer. Because of the direction the Earth faces moving through space, you will usually see far more meteors after midnight local time (1 a.m. Daylight Saving Time).

With the radiant of the Perseids in the northeastern sky, the best directions to look are southeast and northwest. Better still is to lie on your back and look straight overhead.

Many people misunderstand what is meant by a meteor shower. It is a slightly higher frequency of meteors coming from a particular radiating point. On a night without a shower, you will see perhaps five meteors an hour if you watch continuously. At the peak of the Perseid shower under very dark country skies, you should expect to see 90 meteors an hour if you concentrate on looking straight overhead. That’s about three meteors every two minutes.

This year’s Perseid shower is particularly good because the peak falls just after midnight local time for observers in the eastern half of North America, and the moon is close to new and doesn’t rise until after 5 a.m.

The darker your skies, the more faint meteors you are likely to see. Under light-polluted skies, you will see far fewer meteors, as only the brightest ones can be seen.

It’s important to dress warmly, since even in summer the temperature can drop quite low after midnight. I usually wear winter clothes and lie back on a deck chair so that I can see close to overhead. It’s important to spend at least 20 minutes under a dark sky so that your eyes get fully adapted to the dark. Don’t bother with a telescope or binoculars as these take in too little sky. Your best equipment to see meteors is the plain old human eye.

An interesting project is to equip yourself with a star chart of the direction you plan to observe, and then plot the meteors you see on that chart using a red flashlight so that you don’t lose your dark adaptation. If you observe continuously for more than an hour, you should be able to confirm that the radiant is in Perseus.

The Perseids also provide a great opportunity for photography. Point your camera towards the northeast, and leave the shutter open for at least a minute. Do this several times in succession and you’re almost certain to catch a few Perseids.

If you’re clouded out on the night of the peak, try again over the next few nights, as the Perseids have quite broad peak.

Triple Conjunction at Sunset Between The Planets Mercury, Jupiter And The Bright Star Regulus

Over the next few nights, observers with low western horizons may be able to observe a triple conjunction between the planets Mercury and Jupiter and the bright star Regulus.

On Friday, August 7, the two planets and star will form an equilateral triangle, 1 degree on a side. Mercury will be on top, Regulus to the left, and Jupiter to the right.

Look for them with binoculars just after sunset. Jupiter will be in the middle and the brightest of the three, at magnitude –1.7. Mercury will be on the right at magnitude –0.7. Regulus will be the faintest of the three, on the left at magnitude +1.3.

Brightness in astronomy is measured on an upside-down scale where the faintest stars visible to the naked eye are magnitude 6, the brightest stars are around magnitude 0, and really bright objects like the sun, moon, and planets have negative magnitudes.

All three of these objects will be very bright, but will be masked by the brightness of the sky just after sunset. If you wait until the sky has darkened, they will probably be too low to observe.

Three nights later, on Monday, August 10, Mercury will have moved away to the left, but Regulus and Jupiter will have moved closer to each other, less than half a degree apart. This conjunction will be very hard to observe because of its low altitude.

This will probably be your last chance to observe Jupiter before it passes behind the Sun on August 26. Look for it in the morning sky in mid-September.

Sky Events For June 2015

Moon Phases

Full Moon

Tuesday, June 2, 12:19 p.m. EDT

The Full Moon of June is known as the “Mead Moon,” “Strawberry Moon,”  “Rose Moon,” or “Thunder Moon.” It rises around sunset and sets around sunrise; this is the only night in the month when the Moon is in the sky all night long. The rest of the month, the Moon spends at least some time in the daytime sky.

Last Quarter Moon

Tuesday, June 9, 11:42 a.m. EDT

The Last Quarter Moon rises around 1:15 a.m. and sets around 1:15 p.m. It is most easily seen just after sunrise in the southern sky.

New Moon

Tuesday, June 16, 10:05 a.m. EDT

The Moon is not visible on the date of New Moon because it is too close to the Sun, but can be seen low in the East as a narrow crescent a morning or two before, just before sunrise. It is visible low in the West an evening or two after New Moon.

First Quarter Moon

Wednesday, June 24, 5:03 a.m. EDT

The First Quarter Moon rises around 12:30 p.m. and sets around 1:15 a.m. It dominates the evening sky.

Observing Highlights

Double shadow transit on Jupiter

Thursday, June 4, 12:58–2:13 a.m. EDT

The shadows of Io and Ganymede will simultaneously fall on the face of of Jupiter.

Venus at greatest elongation east

Saturday, June 6, evening twilight

Venus reaches its greatest eastward distance from the sun, its orbit shown in white here. It is closing in on Jupiter.

Pallas at opposition

Thursday, June 11, 9 p.m. EDT

Pallas, the second largest asteroid, will be in opposition to the Sun. At magnitude 9.4, it will be located just south of Lambda Hercules, below the “keystone” of Hercules.

Uranus and the Moon

Thursday/Friday, June 11/12

The Moon will be close to Uranus just before sunrise. In southern Australia and the South Pacific Ocean, the Moon will actually occult Uranus, as seen here from Melbourne, Australia.

Mercury and the Moon

Monday, June 15, sunrise

As seen here from Sri Lanka, the Moon will occult the planet Mercury. Other parts of the world will see the thin crescent of Mercury very close to the thin crescent of the moon just before sunrise.

Aldebaran and the Moon

Monday, June 15, sunrise

As seen here from eastern North America, the Moon will occult the bright red giant star Aldebaran.

Solstice

Sunday, June 21, 12:38 p.m. EDT

The sun reaches its most northern point, marking the middle of the astronomical summer season in the Northern Hemisphere, and winter in the Southern Hemisphere. The actual seasons tend to lag behind the astronomical seasons by about 6 weeks.

Mercury at greatest elongation west

Wednesday, June 24, dawn

Mercury will be at its farthest from the sun, and close to the red giant star Aldebaran.

Venus and Jupiter within 0.3 degrees

Tuesday, June 30, dusk

Venus and Jupiter will pass really close to each other, appearing within the same telescope field. Both will be 32 arc seconds in diameter, but Jupiter is much further away from both the Earth and the sun, so will be much fainter than Venus.

Planets

 Mercury is well placed in the eastern sky at dawn. It is better placed for observers in the Southern Hemisphere.

Venus shines high in the western sky after sunset, reaching its greatest elongation from the sun on June 6.

Mars is too close to the Sun to be visible. It will be in conjunction with the sun on June 14.

Jupiter is low in the western evening sky all month, closing in on Venus.

Saturn is just past opposition and shining brightly in Libra all night.

Uranus is in the eastern morning sky in Pisces.

Neptune rises after midnight in the constellation Aquarius.

If you'd like to follow along with NASA's New Horizons Mission to Pluto and the Kuiper Belt, please download our FREE Pluto Safari app.  It is available for mobile devices. Simulate the July 14, 2015 flyby of Pluto, get regular mission news updates, and learn the history of Pluto.

Simulation Curriculum is the leader in space science curriculum solutions and the makers of Starry Night, SkySafari and Pluto Safari. Follow the mission to Pluto with us on Twitter @SkySafariAstro, Facebook and Instagram. 

Sky Events For May 2015

Moon Phases

Full Moon

Sunday, May 3, 11:42 p.m. EDT

The Full Moon of May is known as the “Milk Moon,” “Flower Moon,”  or “Corn Planting Moon.” It rises around sunset and sets around sunrise; this is the only night in the month when the Moon is in the sky all night long. The rest of the month, the Moon spends at least some time in the daytime sky.

Last Quarter Moon

Monday, May 11, 6:36 a.m. EDT

The Last Quarter Moon rises around 2 a.m. and sets around 1 p.m. It is most easily seen just after sunrise in the southern sky.

New Moon

Sunday, May 18, 12:13 a.m. EDT

The Moon is not visible on the date of New Moon because it is too close to the Sun, but can be seen low in the East as a narrow crescent a morning or two before, just before sunrise. It is visible low in the West an evening or two after New Moon.

First Quarter Moon

Monday, May 25, 1:19 p.m. EDT

The First Quarter Moon rises around 1 p.m. and sets around 2:15 a.m. It dominates the evening sky.

Observing Highlights

Mercury at greatest elongation

Thursday, May 7, evening twilight

This is the best evening apparition of Mercury this year for observers in the northern hemisphere. Use Venus to help you locate it. Mercury is most easily located by sweeping with binoculars, but once you’ve located it, you should be able to see it with your unaided eyes

Uranus and the Moon

Friday, May 15, dawn

The Moon will pass just south of the Uranus just before sunrise.

Double shadow transit on Jupiter

Wednesday, May 20, 8:06–8:35 p.m. EDT

The shadows of Io and Ganymede will be on opposite limbs of Jupiter, while the moons Io and Callisto will be central on the disk.

Saturn at opposition

Friday, May 22, 10 p.m. EDT

Saturn will be in opposition to the Sun.

Note how most of Saturn’s moons are in the same plane as the rings, except for Iapetus, whose orbit is tilted 8.3 degrees. At opposition, Iapetus is close to maximum elongation towards the west, while Tycho is close to maximum elongation towards the east.

Double shadow transit on Jupiter

Wednesday, May 27, 10:01 p.m.–12:18 a.m. EDT

The shadow of Io chases the shadow of Ganymede across the face of Jupiter, catching up with it and passing it at 11:48 p.m. EDT. The Great Red Spot will also cross Jupiter’s disk during this period.

Planets

 Mercury is well placed for northern hemisphere observers in the evening twilight sky for the first three weeks of May.

Venus shines high in the western sky after sunset.

Mars moves from Aries to Taurus on May 3, too close to the Sun to be visible.

Jupiter is well placed in the evening sky all month.

Saturn is just north of Scorpius’ “claws.” At opposition on May 22, it is visible all night.

Uranus rises just before the Sun in Pisces.

Neptune is in the eastern morning sky in the constellation Aquarius.

If you'd like to follow along with NASA's New Horizons Mission to Pluto and the Kuiper Belt, please download our FREE Pluto Safari app.  It is available for iOS and Android mobile devices. Simulate the July 14, 2015 flyby of Pluto, get regular mission news updates, and learn the history of Pluto.

Simulation Curriculum is the leader in space science curriculum solutions and the makers of Starry Night, SkySafari and Pluto Safari. Follow the mission to Pluto with us on Twitter @SkySafariAstro, Facebook and Instagram.