The Night Sky This Month (April 2014)

The Planets

Mercury

Mercury is unobservably close to the Sun all month. It passes through superior conjunction on April 25 and then, in early May, jumps into evening visibility.

Venus

Venus is the bright "Morning Star", blazing low in the east-southeast before and during dawn. The planet loses a little of its altitude in April, but at magnitude -4.2 around mid-month you will not have any trouble distinguishing it.

The telescopic appearance of Venus changes dramatically during the month. On the 1st, the planet spans 22 arcseconds and shows a disk about 54-percent lit. By the 30th, Venus' apparent diameter has shrunk to 17 arcseconds, but the disk is then 66-percent illuminated.

Venus, the second of the inferior planets, is almost the same size as the Earth, and is the nearest body in the sky apart from the Moon. Until recently, we knew practically nothing about the surface of Venus, and there were constant references to "the Planet of Mystery". Indeed, until the radar measurements of the 1960s even the rate of rotation of the planet was not known.

It was then found that Venus turns on its axis once every 243 Earth-days, making the planet's day longer than its year! Even more surprising is the fact that the rotation is retrograde. In other words, Venus spins in the opposite direction to the majority of the planets in the solar system.

Map Finder map (early April) - 30 minutes before sunrise, looking southeast.
Finder map (mid-April) - 30 minutes before sunrise, looking east.
Finder map (late April) - 30 minutes before sunrise, looking east.

Mars

Hubble Space Telescope Image of Mars
The Red Planet reaches opposition this month,
and appears bigger through a telescope than
any time until 2016. Philip James/Steven
Lee/NASA
[larger image]
The most spectacular planet this month has to be Mars. April brings the Red Planet closer to Earth than at any time since the winter of 2007. If you have a telescope, even a small one, now is certainly the time to get it out.

Mars pokes above the horizon during evening twilight, among the background stars of the constellation Virgo, and is high up in fine view in the south by midnight local daylight time. It gleams so brightly and with such a distinct ruddy hue, you will not confuse it with any other object. Through a telescope, the planet measures 15 arcseconds across - nowhere near the record-breaking apparent diameter of 25 arcseconds in August 2003, but bigger than Mars will appear again until 2016.

The Red Planet is never easy to
study visually, but this will be your best chance! The best telescope for planetary observing is a large, high-quality refractor or a large Newtonian reflector with first-rate mirrors in perfect collimation (optical alignment). Fine planetary views can also be obtained with Schmidt-Cassegrains; there are no hard and fast rules in this respect.

In the end, the limiting factor is atmospheric seeing. Studying the planets means spending a lot of time at the eyepiece, waiting for brief glimpses through steady air. Just as important, the longer you watch, the better trained your eye becomes.

Map Finder map (early April) - midnight, looking southeast.
Finder map (mid-April) - midnight, looking south.
Finder map (late April) - midnight, looking south.

Jupiter

Gas Giant Jupiter
Viewing the solar system's largest planet can
be more than fun - even with a modest
telescope you can easily see the cloud bands
and Jupiter's largest moons. NASA/ESA
[larger image]
As darkness falls, gas giant Jupiter rides above the western horizon, more than 60° high from mid-northern latitudes. The planet lies in Gemini, near the ecliptic's northernmost point, so it remains visible well after midnight despite being three months past opposition.

Jupiter is the King of the Planets, and not just because of its enormous size - this monster planet is 88,700 miles (142,700 kilometers) in diameter. Jupiter also reigns over the other members of the solar system in the affections of amateur astronomers, because this great ball of gas is just so consistently interesting.

There is always a tremendous variety of interesting phenomena to see when Jupiter is in the sky. The planet shows detail in small telescopes and even the smallest optical aid will show its four bright moons. In
backyard telescopes, you can make out two or three of the darkest cloud bands and as the scope gets bigger, the more you will see.

6-inch telescopes can show multiple bands and the Great Red Spot. Larger scopes can see details in the bands such as texture, loops, and ovals, often in vivid color. Also visible in larger scopes are transits of the moons across Jupiter's surface as well as the inky black dots of the moons' shadows as they transit the planet's disk.

Map Finder map (early April) - midnight, looking west.
Finder map (mid-April) - midnight, looking west.
Finder map (late April) - one hour after sunset, looking west.

Saturn

Saturn and its Largest Moon
A stunning image of Saturn and its largest moon,
Titan, silhouetted against the planet's edge-on
rings. This true-color mosaic was taken May 6,
2012 by NASA's Cassini spacecraft. NASA/JPL-
Caltech/Space Science Institute
[larger image]
Throughout April, Saturn pokes above the horizon roughly three hours after Mars, and lies a good 30° high in the southwest as dawn begins. The ringed planet resides among the background stars of the constellation Libra and shines at magnitude +0.2, two full magnitudes brighter than any of Libra's stars. Through a telescope, Saturn sports an angular size of 18 arcseconds, while the rings span 42 arcseconds and tilt 22° to our line of sight.

Saturn is the most striking  member of our planetary family. With an equatorial diameter of about 75,000 miles (120,700 kilometers), it is the second largest planet circling the Sun. Appearing as a bright yellowish object in our night sky, Saturn presents a maximum apparent
diameter of 20 arcseconds and reaches magnitude -0.2 at opposition, when it lies closest to the Earth. The planet's next opposition will occur next month, on May 10.

Saturn's most attractive feature is, of course, the magnificent ring system. The rings consist of countless particles of water ice, ranging in size from small grains to irregularly shaped pieces generally a few feet across. It is interesting to note that if all of the material of the rings of Saturn were formed into a single moon, the moon would be about the mass of Janus (one of the smallest of Saturn's moons) and only 1/20,000 the mass of the Earth's Moon.

Map Finder map (early April) - 30 minutes before sunrise, looking southwest.
Finder map (mid-April) - 30 minutes before sunrise, looking southwest.
Finder map (late April) - one hour before sunrise, looking southwest.

Uranus

Uranus is in conjunction with the Sun on April 2 and probably impossible to view all month. The distant world will again be visible in backyard telescopes starting around mid-May.

Neptune

Neptune from Voyager 2
Dark, cold and whipped by supersonic winds,
Neptune is the last of the hydrogen and helium
gas giants in our solar system. NASA/JPL
[larger image]
Seek out Neptune just before dawn, in central Aquarius, 1° northeast of the 5th-magnitude star Sigma Aquarii. The planet lies 2.8 billion miles (4.5 billion kilometers) from Earth and glows dimly at magnitude +7.9. A 4-inch diameter telescope is probably the minimum required to see the planet and resolve its disk, only 2.4 arcseconds across.

Neptune is a cold, dark world. With a mean solar distance of 30.11 astronomical units, light levels at Neptune are more than 800 times dimmer than they are on Earth. Noon on Neptune would appear no brighter than what a human would experience at dusk on Earth. Even the Sun would take on an appearance more like a star than the bright disk seen from our home planet.

Because Neptune is so distant, so far
only one spacecraft, Voyager 2, has visited the planet - a flyby in 1989. The spacecraft observed Neptune almost continuously between June and October of that year. It measured the planet's radius and interior rotation rate, confirmed that Neptune has rings, and discovered six new moons. Voyager 2 also recorded pulses of radio emission, zonal cloud bands, and large-scale storm systems with up to 1,500 miles (2,400 kilometers) per hour winds - the strongest measured on any planet.

Map Finder map - field width 15°, stars to magnitude +8.5.

Pluto

Artist's Concept of the New Horizons Spacecraft
Artist's concept of the New Horizons spacecraft,
expected to be the first probe to fly by and study
Pluto and its five known moons. New Horizons'
estimated arrival date is July 14, 2015.
JHUAPL/SwRI [larger image]
Pluto has yet to be visited by unmanned probes (although the Hubble Space Telescope has taken pictures) and, with amateur telescopes, is extremely difficult to detect. It is very faint and, therefore, virtually indistinguishable from surrounding stars, except for its movement.

The dwarf planet lies in northern Sagittarius and stands 25° high in the south shortly before dawn. It glows dimly at magnitude +14, which means you will need at least an 8-inch telescope to have a decent chance of spotting this glimmer of light. The reward for spying Pluto comes not from viewing any detail but from the mere accomplishment of locating this small icy world.

The two finder maps below will help you identify Pluto. First, locate its general position on the coarse finder map, and after you have identified the 7th-magnitude guide star HD 175876 use the fine finder map that shows the position of the dwarf planet on each night of the month.

Map Coarse finder map - field width 10°, stars to magnitude +8.5.
Fine finder map - field width 1°, stars to magnitude +14.5.

The Deep Sky

In the north of the sky, in a region bounded by Ursa Major, Arcturus and the Bowl of Virgo, can be seen what looks like a large, faint star cluster. This is actually the constellation Coma Berenices, given permanent status in 1551 by Gerardus Mercator, from stars previously regarded as belonging to Leo. It supposedly represents the hair of Queen Berenice of Egypt, which she cut off in gratitude to the gods for the safe return of her husband from battle.

Coma Berenices is not a large constellation, yet it contains no less than eight Messier objects. Furthermore, in the background are many galaxies, some brighter than magnitude +10. A good example is NGC 4565, possibly the most prominent of needle-thin edge-on galaxies in the heavens.

Edge-on Galaxy NGC 4565
Magnificent edge-on galaxy NGC 4565 is about 40
million light years distant and spans some 100,000
light years. Ken Crawford [larger image]
NGC 4565, also known as the Needle Galaxy or Caldwell 38, is the largest edge-on spiral galaxy in the night sky. It is quite similar to our Milky Way, although NGC 4565 is slightly more massive (our Galaxy has a mass of about eight hundred billion suns). The Needle Galaxy contains at least two hundred globular clusters and is thought to have a dark matter halo with a mass of several hundred billion suns.

NGC 4565 is located 1.7° east of the star 17 Comae Berenices, and less than 3° from the North Galactic Pole. Through an 8-inch telescope, you will see a streak roughly 10 arcminutes long but only 1.5 arcminutes thick, oriented northwest to southeast. As you increase the telescope's aperture, the apparent length of the Needle Galaxy also increases. A 16-inch scope shows NGC 4565's full extent.

A dark dust lane runs the entire length of the galaxy, masking much of the arms' brightness. The central region features a small bulge, and that is the easiest place to detect the dust lane. The dark streak is offset a little to the north of center because NGC 4565 is inclined to an angle of 87°, 3° from edge-on.

Map Finder map - field width 15°, stars to magnitude +8.5.

Asteroids

Wilhelm Olbers' Primary Instruments
Olbers' primary instruments: two five feet (1.5
meters) focal length telescopes, two "comet
seekers" and a refractor on the right, and a
pendulum clock in the background for the
measurement of time. Wilhelm Olbers - "Sein
Leben und Seine Werke"
[larger image]
Since the first night of the 19th century, when Father Giuseppe Piazzi discovered Ceres, we have noted and cataloged more than 625,000 asteroids with regular orbits, most of them concentrated in the main-belt between the orbits of Mars and Jupiter.

Most main-belt asteroids have reasonably circular orbits and revolve around the Sun in roughly the same plane as the planets. As a result, they never stray far from the ecliptic - the dotted curved line on the circular all-sky map. However, some are highly inclined by 35° in the case of 2 Pallas, for example. It is likely that this asteroid suffered a big collision during the solar system's early days, which modified a more typical orbit.

German amateur astronomer Heinrich Wilhelm Olbers
discovered Pallas in 1802 while looking for the first asteroid, Ceres. Olbers - best known for posing Olbers' paradox: "Why is the sky dark at night?" - also discovered the brightest asteroid (4 Vesta) and several comets. Pallas turned out to be a bit more than 330 miles (530 kilometers) in diameter, making it the second-largest object in the asteroid belt.

Despite its large size, Pallas looks like an ordinary field star glowing at 8th magnitude. The asteroid spends April at the border between the constellations Hydra and Leo, a region that lies highest in the south during early evening. On April 2, Pallas passes just 0.5° west of 5th-magnitude 2 Hydrae, a spectral class "K" star located three hundred light years away. The asteroid moves due northeast from there, and by late April it lies 3° west of Regulus, Leo's brightest star.

Map Finder map - field width 15°, stars to magnitude +9.

Comets

Comet C/2012 X1 LINEAR
C/2012 X1 LINEAR underwent a large outburst in
mid-October 2013. Pictured above on January 23,
the comet is still bright and gets gradually higher
in the morning sky. Damian Peach [larger image]
Although never expected to become brighter than 14th-magnitude, in mid-October 2013 comet C/2012 X1 LINEAR suddenly brightened some 150 times to magnitude +8. Something similar happened with comet 17P/Holmes in 2007, when the "icy mud ball" brightened over half a million times from an uber-faint 17th-magnitude to a naked eye brightness of +2.8.

While cometary outbursts are common, their causes are unknown. One possibility is that a massive buildup of gas inside the comet fractures and breaks off a large size of the crust, releasing a huge cloud of dust and gas. Another possibility is that outbursts are triggered by impacts with bodies that have sizes in the range of three or four feet (one meter).

Throughout all of April, C/2012 X1 should remain around 8th or 9th magnitude, making it an easy target for 6-inch telescopes. The comet cuts through the constellation Aquarius the Water-Bearer, which stands highest above the horizon in the predawn sky. The best views will come during the month's first and last weeks, when moonlight will not interfere with observing.

Use a range of magnifications to see all of the comet's features. If you bump up the power past 100x, you might even glimpse the "false nucleus", a pinprick shining in the middle of the brightest glow. The true surface of C/2012 X1 LINEAR lies hidden behind several bright layers of dust and gas, ejected in the previous several days.

Map Finder map - field width 20°, stars to magnitude +8.5.

C/2012 K1 PanSTARRS was discovered on May 19, 2012, using the PanSTARRS robotic telescope located near the summit of Haleakala, on the island of Maui in Hawaii. Glowing around 10th magnitude, this visitor from the outer solar system likely will appear similar in brightness and size to the brighter galaxies in the Messier catalog.

As April opens, PanSTARRS lies in Corona Borealis, 10° west of the great globular star cluster M13 in Hercules. By month's end, the comet skims between Eta Ursae Majoris (the star at the end of the Big Dipper's handle) and M51, the Whirlpool Galaxy. This encounter should deliver a spectacular time-lapse sequence for digital photographers.

In order to view comets, the first thing to consider is using good binoculars or a decent telescope. Although any kind of telescope can be used for comet observing, a short focal length instrument will deliver the best views. These kinds of telescope will give you a much larger field of view with a given eyepiece, hence increasing the contrast between faint comets and the background sky.

Map Finder map - field width 40°, stars to magnitude +6.

Discovery Images of Comet Jacques
Discovery images of C/2014 E2 Jacques, taken with an 18-inch (0.45
meter) reflector at the SONEAR Observatory. The comet is the fuzzy
blob near the center of each frame. SONEAR [larger image]
C/2014 E2 Jacques is a new bright comet, discovered last month by Cristovao Jacques and the SONEAR
team at an observatory near Oliveira, Brazil. The preliminary orbit indicates that the comet will approach to the Sun down to 60 million miles (96 million kilometers) in July, when it is expected to brighten to magnitude +7.

Before the perihelion passage, from mid-northern latitudes, Comet Jacques will be observable until mid-May. After perihelion, starting mid-July, the comet will emerge in the morning sky and will swing north from Taurus into Cepheus and Perseus.

During April, C/2014 E2 Jacques travels northwestward from Antlia into Monoceros. From the Northern Hemisphere this region climbs highest in the early evening, above the southern horizon. Glowing at 10th-magnitude, the comet should have a bright core surrounded by a small and faint halo, about two arcminutes across. This halo will disappear under light-polluted skies, however, so try to find as dark an observing site as you can.

Map Finder map - field width 60°, stars to magnitude +6.

Meteors

The Lyrid shower is the oldest meteor shower for which observations have been found. Recorded sightings go back more than 2,000 years, when the shower was much more abundant. Despite the low annual rate, the Lyrids have the capacity for impressive displays - over 50 falling stars per hour. This last happened in 1982, when the rate unexpectedly reached 90 meteors per hour.

This year, astronomers predict that the shower will climb to a sharp peak in the predawn hours of April 22. However, activity begins on April 16 and continues until about the 25th. The radiant is located in a region of the sky between the constellations Lyra and Hercules (check the map below), and is overhead around 5 A.M. local daylight time.

The best time to observe is just before dawn, when the night side of Earth faces into its orbit, thus sweeping up more meteoric debris. Most Lyrid meteors are bright and rather fast (30 miles/48 kilometers per second), and about 20-percent leave persistent luminous trains.

Map Map - Lyrids radiant position.

The Eta Aquariids may not be as spectacular as the Perseids in August or the Leonids of winter, but it is fun to think that these meteors are in fact particles of the most famous comets of all - Halley's Comet! The shower gets its name from the area of the sky from which the meteors appear to radiate at the date of the maximum, in this case, a star designated by the Greek letter Eta in the constellation Aquarius the Water-Bearer.

The Eta Aquariids first appear around April 19, and some can be seen until May 28. The shower's peak occurs around May 6, when up to 20 or 30 meteors can be seen each hour from a dark-sky site. Rates are higher the farther south you are located, and for observers in the Southern
Halley's Comet
The Eta Aquariids are flakes of dust from Halley's
Comet (pictured above), which make brilliant
shooting stars when they strike Earth's
atmosphere. ESA [larger image]
Hemisphere the hourly rate climbs to 55. Before and after the maximum, the Eta Aquariids produce only two or three meteors per hour.

Throughout April, the shower's radiant is found in western Aquarius close to Beta Aquarii, and moves daily a little to the northeast. The radiant never gets very high in the sky before dawn, so your observing time is limited. Many Eta Aquariid meteors are bright yellow, and some will likely leave brief smoke trails in their wake.

Map Map - Eta Aquariids radiant position.

Some meteors do not belong to any known shower. These are the sporadic meteors, caused by random bits of comet debris spread throughout the inner solar system. They appear randomly across the sky all year long.

In this month's night sky careful observers can expect around five sporadics per hour during the morning hours and two during the dark evening.

Observing Aids

Map Northern Hemisphere's Sky - This map portrays the sky as seen near 40° north latitude at 10 P.M. local daylight time in early April and 9 P.M. in late April.

Map Southern Hemisphere's Sky - This map is plotted for 35° south latitude. It shows the sky at 8 P.M. local time in early April and 7 P.M. in late April.

Map Visibility of the Planets - The table provides general information about the visibility of the planets during the current month.

Map Phases of the Moon - This Moon Phase Calendar shows the Moon's phase for every day in April.

Map Jupiter's Moons - The diagram shows the positions of Galilean satellites on each day in April at midnight.

Sky Events

April 2 - 3 A.M. EDT: Uranus is in conjunction with the Sun.

April 7 - 4:31 A.M. EDT: First Quarter Moon.

April 8 - 10:52 A.M. EDT: The Moon is at apogee, the point in its orbit when it is farthest from Earth. 5 P.M. EDT: Mars is at opposition.

April 11 - 3 A.M. EDT: Asteroid 3 Juno is in conjunction with the Sun.

April 12 - 4 A.M. EDT: Venus is 0.7° north of Neptune.

April 13 - 8 A.M. EDT: Asteroid 4 Vesta is at opposition.

April 14 - 2 P.M. EDT: The Moon is 3° south of Mars. 9 P.M. EDT: Pluto is stationary.

April 15 - 2 A.M. EDT: The dwarf planet Ceres is at opposition. 3:07 A.M. EDT: A total lunar eclipse is visible from North and South America, east Australia, New Zealand, and the Pacific (Read More). 3:42 A.M. EDT: Full Moon.

April 17 - 3 A.M. EDT: The Moon is 0.7° south of Saturn.

April 22 - 3:52 A.M. EDT: Last Quarter Moon. 5 A.M. EDT: The Lyrid meteor shower is at peak activity. 8:24 P.M. EDT: The Moon is at perigee, the point in its orbit when it is nearest to Earth.

April 25 - 7 P.M. EDT: The Moon is 4° north of Venus. 11 P.M. EDT: Mercury is in superior conjunction with the Sun.

April 29 - 2:04 A.M. EDT: An annular solar eclipse is visible from parts of Antarctica and Australia. 2:14 A.M. EDT: New Moon.

The information provided on this page is accurate for the world's mid-northern latitudes. Finder maps for the five naked eye planets are plotted for 40° north latitude, but can also be used from other latitudes close to 40° north. Except the two all-sky maps, all other maps can be used no matter the latitude. Local time (local daylight time during summer) represents the time of the reader.

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