Venus Kisses Saturn On Friday Jan. 8

On Friday, January 8, the planet Venus will appear to pass just 5 arc minutes north of the planet Saturn, That is a mere one-sixth of the diameter of the moon, a small enough distance to fit in the eyepiece of a powerful telescope.

On January 9, the planet Venus will appear to pass just north of the planet Saturn. Credit: Starry Night software.

This will be a rare opportunity to see two planets at the same time in a telescope’s narrow field of view. In a lifetime of observing the skies, I have seen such a close conjunction of two planets only two or three times. With the naked eye, sharp-eyed observers will be hard pressed to separate the two points of light.

Unfortunately for observers in North America, the point of closest conjunction will occur at 11 p.m. EST, while the planets are below the local horizon. For a skywatcher in New York, for example, the planets won’t clear the eastern horizon until 5 a.m. EST, at which time they will have separated so that they are 17 arc minutes apart, or slightly more than half the diameter of the moon. Even so, they will still fit in a telescope eyepiece.

Of course, this conjunction is something of an optical illusion. The two planets aren’t anywhere near each other in space, but merely appear close together from our perspective here on planet Earth.

Venus is currently on the far side of the Sun from Earth, 1.22 astronomical units distant (1.22 times the average distance from the Earth to the sun), so it appears similar to a gibbous moon.
Saturn is 10.79 astronomical units from Earth, nearly 9 times farther away than Saturn.

The two appear almost the same angular diameter: 14 arc seconds for Venus, 15 arc seconds for Saturn, yet in reality Saturn is actually almost 10 times the diameter of Venus. So Saturn’s greater distance balances out is larger size, and the two appear almost the same from Earth.

The most striking difference between the two is their difference in brightness. Venus is magnitude –4.0 on the upside-down brightness scale astronomers use, while Saturn is only magnitude +0.5, 4.5 magnitudes (or almost 100 times) fainter than Venus. This difference is mainly due to Venus’ closeness to the sun (0.72 astronomical units) compared to Saturn’s (9.55 astronomical units).

When you look for the twin planets just before dawn on Saturday morning, the first thing you will notice is Venus shining brightly in the southeastern sky. You will have to look closely to spot “tiny” Saturn just above and to the right of it.

If you own a planetarium program like Starry Night that lets you travel to other planets, check out the view Saturday morning from Saturn. You will see Earth and Venus in a close conjunction, Venus a narrow crescent from Saturn’s perspective, and Earth a rounded gibbous shape, since despite being close in the sky, they are actually on opposite sides of the sun, and lit by it quite differently.

Sky Events For September 2015

Moon Phases

Saturday, September 5, 5:54 a.m. EDT

Last Quarter Moon

The Last Quarter Moon rises around 11:30 p.m. and sets around 3 p.m. It is most easily seen just after sunrise in the southern sky.

Sunday, September 13, 2:41 a.m. EDT

New Moon

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.

Monday, September 21, 4:59 a.m. EDT

First Quarter Moon

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

Sunday, September 27, 10:51 p.m. EDT

Full Moon

The September Full Moon is known as the Harvest Moon or Full Corn 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.

Observing Highlights

Neptune at opposition

Tuesday, September 1, midnight

Neptune will be directly opposite the Sun in the sky, and visible all night. It is located in Aquarius but is too faint to be seen with the unaided eye. Use binoculars and a star chart from Starry Night.

Mercury at greatest elongation east

Thursday and Friday, September 3 and 4, dusk

Mercury will be well placed in the evening sky for observers in the southern hemisphere, less so for observers in the north.

Aldebaran and the Moon

Friday/Saturday, September 4/5, near midnight EDT

Observers on the eastern part of North America with low eastern horizons may be able to see the Moon occult the first magnitude star Aldebaran just after moonrise (around midnight, but check for local times). Observers in Europe will see it just before sunrise on the 5th.

Zodiacal light

Friday, September 11–Thursday, September 24, before dawn

The best time in the year to see the dim glow of the zodiacal light in the pre-dawn eastern sky, the light reflected from millions of interplanetary particles. It lies along the ecliptic (shown in green).

Partial solar eclipse

Sunday, September 13

This eclipse will be visible from southern Africa, Antarctica, and the oceans in between. Seen here is the maximum eclipse in Cape Town, South Africa.

Equinox

Wednesday, September 23, 4:21 a.m. EDT

The Sun crosses the celestial equator moving southward, causing the days to grow shorter in the northern hemisphere and longer in the southern hemisphere.

Lunar trio

Sunday, September 27, evening

There will be a triple treat for observers in eastern North America as sun, Earth, and moon align: a total lunar eclipse, the moon at its closest, and a full moon, all in one evening. At 8:12 p.m. EDT, the lunar eclipse will begin with the first faint lunar shadow creeping onto the moon. At 9:48, the moon reaches an extreme perigee, the closest it will get to Earth in all of 2015: 221,753 miles (356,877 km). Total phase of the eclipse will begin at 10:11 p.m. and mid eclipse will be at 10:47. At 10:51 it will be the instant of full moon, the largest full moon in 2015. At 11:23, the total phase of the eclipse will end, and at 1:23 a.m. the last of the moon’s shadow will leave the moon. In western North America, the moon will already be in eclipse when the moon rises. Observers in South America, Europe, and Africa will also see most of this eclipse. The illustration shows the moon just entering the umbral shadow of Earth at 9:12 p.m. EDT.

Vesta at opposition

Monday, September 28, 11 p.m. EDT

The brightest asteroid Vesta will be directly opposite the Sun and visible all night in Cetus. At magnitude 6.2, it will be right at the limit of naked-eye visibility, but easily spotted with binoculars.

Planets

Mercury is well placed in the evening twilight for the first half of the month. This apparition is more favorable for observers in the Southern Hemisphere.

Venus is now a bright object in the pre-dawn sky, reaching maximum brightness of magnitude –4.8 on the 21st.

Mars is low in the eastern twilight, moving eastward through Cancer into Leo.

Jupiter reappears in the eastern pre-dawn sky in the middle of the month..

Saturn is low in the southwest mid-evening sky, and sets in late evening.

Uranus rises in mid-evening in Pisces, nearing opposition on October 12. 

Neptune is in opposition on the 1st, visible all night in the constellation Aquarius.

Sky Events For August 2015

Moon Phases

Thursday, August 6, 10:03 p.m. EDT

Last Quarter Moon

The Last Quarter Moon rises around midnight and sets around 3 p.m. It is most easily seen just after sunrise in the southern sky.

Friday, August 14, 10:53 a.m. EDT

New Moon

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.

Saturday, August 22, 3:31 p.m. EDT

First Quarter Moon

The First Quarter Moon rises around noon and sets around midnight. It dominates the evening sky.

Saturday, August 29, 2:35 p.m. EDT

Full Moon

The August Full Moon is known as the Corn Moon, Sturgeon Moon, Red Moon, Green Corn Moon, or Grain 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.

Observing Highlights

Uranus and the Moon

Wednesday/Thursday, August 5/6, dawn

The Moon will be close to Uranus just before sunrise. In southern South America, the Falkland Islands, and parts of Antarctica, the Moon will actually occult Uranus.

Mercury and Jupiter within 0.6 degrees

Thursday, August 6, dusk

Mercury and Jupiter will pass close to each other, appearing within the same telescope field.

Mercury, Jupiter and Regulus within 1 degree

Friday, August 7, dusk

These three bright objects will form a tight triangular pattern low in the western sky after sunset.

Aldebaran and the Moon

Saturday, August 8, early morning

The waning crescent moon will pass close to the bright red star Aldebaran low in morning twilight. The Moon will occult Aldebaran as seen from the Middle East, eastern Europe, northwestern Asia, Scandinavia, Russia, Alaska, and northwestern Canada.

Jupiter and Regulus within 0.5 degrees

Monday, August 10, dusk

Jupiter will pass just north of the bright star Regulus in the constellation Leo.

Perseid meteor shower peaks

Thursday, August 13, 2 a.m.

The Perseid meteor shower is always the most reliable in the year, and this year benefits from having the moon out of the sky for most of the night. Although Perseid meteors can be seen at any time of night, there are always more meteors after midnight because then the Earth is heading directly into the shower. Although they appear to radiate from a point in the constellation Perseus in the northeastern sky, they can be seen anywhere in the sky.

Mars in the Beehive

Thursday, August 20, before dawn

Mars, just past conjunction with the sun, passes in front of the Beehive Cluster, Messier 44.

Moon close to perigee

Saturday, August 29, 8 p.m. local time

The moon will be closest to the Earth at 11 a.m. on August 30, 222,631 miles or 358,290 km. distant. The moon will be below the horizon at that time for observers in North America. The best time to observe this “supermoon” will be just after it rises on Saturday night, August 29. Those living near the ocean should expect higher tides than normal for the next few days.

Planets

Mercury is visible low in the western sky after sunset for most of the month, This apparition is more favorable for observers in the Southern Hemisphere.

Venus moves from the evening to the morning sky on the 15th, but will be hard to observe for northern observers because of its closeness to the sun. Southern observers will have an easier time, and on the 15th may actually be able to observe Venus as a morning star in the east and an evening star in the west.

Mars reappears in dawn twilight after its conjunction with the sun on June 14.

Jupiter is too close to the sun to observe this month.

Saturn is well placed in Libra in the evening sky.

Uranus rises in the late evening in Pisces. 

Neptune rises in the mid-evening in the constellation Aquarius.


Find The Brightest And Nearest Of The Dwarf Planets

With all the news this past week about Pluto, most skywatchers arent aware that Ceres, the brightest and nearest of the dwarf planets, will be coming into opposition to the sun on Saturday morning, July 25.

An object is said to be in opposition when it is directly opposite the sun in Earths sky. When an object is in opposition, it rises at sunset, is visible all night, and then sets at sunrise.

When Ceres was discovered by Giuseppe Piazzi on the first day of the 19th century, January 1, 1801, it was initially thought to be a planet. Other objects were soon discovered in the gap between the orbits of Mars and Jupiter, so a new name was proposed for these tiny bodies, asteroids. This was because of their resemblance to stars in the telescopes of the day.

When the International Astronomical Union proposed a new category, dwarf planet, in 2006, Ceres was included, along with Pluto, Eris, Haumea, and Makemake. So tiny Ceres has been called three different things in the 214 years since it was discovered: planet, asteroid, and now dwarf planet.

Despite its recent designation as a dwarf planet, Ceres is still considered to be an asteroid by most astronomers. As such, it is the largest of the asteroids at 592 miles (952 km) in diameter, almost twice the diameter and four times the mass of the next largest asteroids, Pallas and Vesta. On the other hand, it is far smaller than any of the other designated dwarf planets. It is also smaller than fifteen of the moons in the solar system, including Earths moon.

This year, Ceres reaches opposition just on the Sagittarius side of the border between Sagittarius and the little-known constellation Microscopium. It is most easily found by looking within the triangle formed three 4th magnitude stars: 62 Sagittarii, the easternmost star in Sagittarius, Omega Capricorni, the southernmost star in Capricornus, and Gamma Microscopii, the brightest star in the dim constellation Microscopium, the Microscope.

On Saturday morning, July 25, the dwarf planet Ceres will be in opposition to the sun on the border between Sagittarius and Microscopium. Credit: Starry Night software.

Because of its faintness, magnitude 7.5 at opposition, detailed charts are needed to distinguish Ceres from the stars its passing in front of. Our chart shows its position on the morning of opposition, Saturday, July 25. If you try to find it on any other night, you will need to plot its position with a program like Starry Night or SkySafari.

A detailed chart for locating 7th magnitude Ceres on July 25. Credit: Starry Night software.

As seen in even the largest telescopes on Earth, Ceres appears as a point of light, no different than the background stars. The only way to be sure you have seen it is to plot its position and then try to observe the same area on another night.

On March 6 this year, the Dawn spacecraft entered orbit around Ceres, and has since been returning detailed images of Ceres surface. Thus, 2015 marks a special year for the exploration of the solar system, with Dawn orbiting Ceres and New Horizons flying close to Pluto.

Venus and Jupiter, Up Close and Personal

If youve been watching the western sky just after sunset lately, you will have noticed two bright objects, gradually drawing closer.

These are the two brightest planets, Venus and Jupiter. Venus is the brighter of the two, currently magnitude 4.6 on the upside-down brightness scale astronomers use. It will get slightly brighter over the next 10 days, reaching greatest brilliancy on July 10 at magnitude 4.7.

Jupiter is somewhat fainter at magnitude 1.8, down from a maximum of 2.6 when it was in opposition on February 6.

Although the two planets look very close in Earths sky, they are in fact very far apart, on opposite sides of the sun. The first graphic shows their true positions, as seen from far above the suns north pole. Venus is slightly nearer Earth than the sun, 0.512 astronomical units distant (47.6 million miles or 76.5 million km.) while Jupiter is 6.083 astronomical units away (565 million miles or 910 million km.) on the far side of the sun.

Seen from far above the suns north pole on Wednesday, July 1, Earth, Venus and Jupiter lie almost on a perfect straight line.  Credit: Starry Night software.

Viewed in a telescope, the two planets are, by coincidence, exactly the same apparent size, 32 arc seconds in diameter, about a 60th of the apparent diameter of the moon, but look very different.

Seen in the eyepiece of a telescope magnifying 65 times at sunset on July 1, Venus and Jupiter appear very close, but look very different, even though both are the same angular size. Credit: Starry Night software.

Venus, with its bright cloud cover and closeness to the sun, is a brilliant white crescent, lit from slightly behind because it is moving between us and the sun. Jupiters cloud tops are somewhat darker than Venus, but it is also more than seven times farther away from the sun. As a result, despite its large size, Jupiter appears much fainter in a telescope than Venus.

Two bright planets in close proximity make a striking sight with the naked eye. In binoculars you should be able to see that Venus is a tiny crescent and Jupiter is a disk accompanied by 3 tiny moons (on July 1, Callisto will be behind Jupiter). A small telescope will make the view much clearer.

As you continue to watch these two planets over the next few weeks you will see them draw apart as both get closer to the sun, Venus passing between us and the sun on August 15, and Jupiter passing behind the sun on August 26. In another month, both will reappear in the morning sky, where they will join Mars, which passed behind the sun on June 14.

 

Spot Mercury At Dawn

Mercury is always a difficult object to spot, always clinging closely to the suns apron strings. But you might be excused for missing its brief appearance this week in the dawn skies.

After many attempts to observe Mercury, Ive found that the best time to spot it is about half an hour before sunrise in the morning sky, or half an hour after sunset in the evening sky. Its always a balancing act between Mercurys low altitude and the brightness of the background sky. I find 7x50 or 10x50 binoculars helpful in spotting Mercury, though once Ive located Mercury in binoculars I usually have no trouble seeing it naked eye.

Unless youre paying close attention to the sky, youre likely to miss the current apparition of Mercury. In the northern hemisphere, Mercury can be seen half an hour before sunrise. Credit: Starry Night Software.

Because of the tilt of the ecliptic, the path the Sun and planets follow across the sky, some apparitions of Mercury are more favorable than others. Usually apparitions which are favorable for observers in the northern hemisphere are unfavorable for observers in the southern hemisphere, and vice versa.

The tilt of the ecliptic would indicate that this apparition favors southern observers, but as you can see from these two views, it really isnt much different: catching Mercury this week will be a challenge for observers everywhere in the world.

A secondary factor affecting Mercurys visibility is the tilt and eccentricity of its orbit. At 7 degrees, Mercurys tilt is greater than any other planet. The eccentricity of its orbit, which measures how far it deviates from a circle, is also the greatest, more than twice as eccentric as Mars orbit.

The tilt this week also favors southern observers, as you can see in the charts, where Mercurys orbit is marked in red and the ecliptic in green, but even this doesnt help much.

The view is not much better in the southern hemisphere. Credit: Starry Night software.

If you are successful in spotting Mercury in the next few days, congratulate yourself, and let us know here!

Venus At Its Brightest

If youve been watching the sky in the early evening lately, you cant have missed seeing the planet Venus in the west.

Venus has been travelling around its orbit towards us, appearing in evening twilight higher and higher in the sky. This week on Saturday, June 6, it reaches its greatest angular distance from the sun, 45 degrees, at what is called greatest elongation east. Even though we are looking at it in the western sky, it is elongated in the direction of the eastern horizon, so it is east of the sun in astronomical terminology.

As seen in a small telescope, Venus this week appears like a brilliant miniature first quarter moon. However, unlike the moons pock-marked surface, Venus appears perfectly smooth. Thats because we are seeing only the tops of its dense clouds, which mostly appear a featureless blank white.

Beneath those bland clouds lies one of the most bizarre of alien worlds: the greenhouse effect gone wild with a terrain of bare rock heated to a uniform world-wide temperature of  864 degrees Fahrenheit (462 degrees Celsius), where the endless clouds rain down sulfuric acid.

There are, in fact, vague shadings in the surface of Venus clouds. These are best seen with a deep violet filter such as the Wratten 47 available in most telescope stores. It also helps to observe Venus in a daylight sky, when much of its glare is cancelled by daylight.

Whenever Venus is close to elongation, we begin to hear many reports of UFOs in the western sky. Venus is so bright that even experienced stargazers are sometimes taken by surprise.

Over the next few weeks, Venus will begin to move closer to the sun at twilight, actually passing between Earth and sun on August 15.

Most of the planets are so small and far away that they appear as star-like dots in most binoculars. Venus is the exception to this. Study it closely with binoculars over the next few weeks, and you will see it first as a tiny half-moon, then gradually getting larger in size but with a thinner crescent shape as it draws nearer the Earth.

Because Venus orbit has a slightly different tilt than Earths orbit, Venus usually passes above or below the sun, rather than passing directly in front of it. This August it will pass just 8 degrees south of the sun.

Twice so far this century, the orbits of Earth and Venus crossed with both planets in exactly the right position, and Venus was visible in front of the sun. Unfortunately the next such transit of Venus will not occur until the year 2117. I was lucky enough to have clear skies for both the transits of Venus in 2004 and 2012, and seeing the tiny black dot of Venus through a solar filter was a highlight of my observing life.


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 for iOS and Android.  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 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, 12:582:13 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

Observing Saturn

On Friday, May 22, at 10 p.m. EDT, Saturn will be in opposition to the sun. This means that it will be directly opposite the sun in our sky. It will rise as the sun sets in the evening, shine brightly all night long, and set as the sun rises at dawn.

On May 22, Saturn reaches opposition with the Sun. It will be right on the border between Libra and Scorpius, just above the three stars which form the Scorpions claws. Credit: Starry Night software.

If you just look at the sky on a single night, everything seems quite static. But if you watch Saturn over a period of a few weeks and note its position against the background stars, you will see that it is in constant motion.

Currently Saturn is moving with what is called retrograde motion, from left to right against the background stars. This is actually an optical illusion caused by the Earths much more rapid movement around the sun. Once the Earth is well past Saturn in early August, Saturn will appear to reverse directions and begin moving in its true direction, from right to left.

This retrograde motion puzzled early skywatchers, who though the planets must go around it tiny circles called epicycles. This was because they incorrectly believed that the Earth was fixed in space and everything revolved around it, the geocentric theory. Once Copernicus made clear that the sun, not the Earth, was the center of the Solar System, the geometry of the planets motion became much simpler.

Saturn, like all the planets, is much smaller in angular size than most people realize. I once tried an experiment to see how much magnification was needed to see Saturns rings. With a binocular magnifying 10 times, Saturn looked just like a bright star. With a 15x binocular, I could just see a hint that Saturn was oval rather than round. It took a telescope magnifying 25 times to see Saturns true shape, though even then no detail was visible. I generally use magnifications of 150 to 250 times to see the details of Saturn and its ring system.

Saturn really has multiple rings, of which the brightest are the outer A ring and the inner B ring. The A ring is noticeably darker than the B ring, and the two are separated by the dark Cassini Division, named after 17th century Italian astronomer Giovanni Domenico Cassini, who was the first to observe it in 1675. Cassini also discovered four of Saturns five brightest moons.

The Cassini Division separates the A and B rings.

Titan, the largest and brightest of Saturns moons was discovered in 1655 by Dutch astronomer Christiaan Huygens. It is visible in even the smallest telescopes. It is the second largest moon in the Solar System (after Jupiter's moon Ganymede), the only moon to have a dense atmosphere, and the only moon other than our own to have been landed on by a spacecraft.

Huygens was also the first person to deduce that Saturns rings were flat circular objects in the plane of Saturns equator. Further study has shown that they are made up of thousands of tiny fragments of rock and ice. I once watched a star pass behind these rings, and the star continued to be visible, since there is more empty space that rock and ice in the rings, making them translucent.

Saturns smaller moons are worth looking for if you have a good telescope. The brighter ones are visible in a 90mm telescope. Because they are in constant motion around Saturn, you need a planetarium program like Starry Night to identify which ones are visible on a given night. Most of the bright moons move in the same plane as the rings, so appear to trace ovals around the planet.

In a telescope at about 150 power, Saturn is small but beautiful in its perfection, the jewel of the Solar System. Look around the planet for its brightest moons. Credit: Starry Night software.

Iapetus is a particularly interesting moon. Its orbit lies outside those of the other bright moons, and is tilted at an angle of 15 degrees compared to the other moons and the rings. Like all major moons in the Solar System, Iapetus always keeps one face permanently turned towards its planet. The side of Iapetus which leads it around in its orbit has encountered a large amount of debris, painting that face of the moon dark black. When that blackened side of Iapetus is facing Earth, at the moons greatest elongation east, it is almost two magnitudes fainter than when the trailing side of Iapetus is facing us, at greatest western elongation.

Right now Iapetus is close to its western elongation, so is at its brightest, magnitude 10.1. By greatest elongation east on June 27, it will be at its faintest, magnitude 11.9.

The globe of Saturn itself is rather bland when compared to its more active neighbor Jupiter. It shows a system of darker belts and brighter zones, but their contrast is muted compared to Jupiter. From time to time bright spots have been observed in Saturns cloud tops, but they have short lives compared to cloud features on Jupiter. In large telescopes, the polar regions of Saturn take on an olive green color.

It is interesting to observe the pattern of shadows on Saturn. The rings cast shadows on the globe of the planet, and the planet in turn casts its shadow on the rings. I have observed these shadows in a telescope as small as 90mm aperture under steady seeing conditions.

Whenever I observe Saturn in a telescope, I always take a few minutes to just sit back and admire its sheer beauty. Saturn was one of the first objects I looked at when I got my first telescope as a teenager, and I still recall the wonder I felt at witnessing this beauty for the first time with my own eyes: It really has rings!


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

Astronomical Audio Pronunciation Guide

Some astronomical monikers truly do seem alien, and ensuring correct pronunciation can be hazardous for even the most advanced educator. Starry Night Education is here to help with our Audio Pronunciation Guide for the top 500 most commonly mispronounced astronomical objects, from Acamar through Zubeneschamali.

Choose your category:
asteroids
constellations
planets
meteors
stars

     
Click the name to hear the correct pronunciation.

Asteroids

 
 
Name
Pronunciation
 
ANN-FRANK
 
a-PAW-fis
 
a-STREE-a
 
BACK-us
 
BRAIL
 
SEER-eez
 
e-JEER-ee-a
 
EER-os
 
ewe-NOM-ee-a
 
FLOOR-a
 
for-TUNE-a
 
HEE-bee
 
hy-GEE-a
 
eye-REE-nee
 
EYE-ris
 
JEW-noe
 
ka-LYE-o-pee
 
lew-TEE-sha
 
ma-SALL-ee-a
 
mel-POM-e-nee
 
MEE-tis
 
PAL-as
 
par-THEN-o-pee
 
SYE-kee
 
SIL-vee-a
 
the-LYE-a
 
THEE-tis
 
VES-ta

Constellations

 
 
Name
 
Pronunciation
 
an-DROM-eh-da
 
ANT-lee-uh
 
APE-us
 
ack-KWAIR-ee-us
 
ack-WILL-lah
 
AY-rah
 
AIR-ease
 
or-EYE-gah
 
bow-OH-tease
 
SEE-lum
 
ca-MEL-oh-PAR-dal-iss
 
KAN-surr
 
KAN-es veh-NAT-ih-see
 
KANE-es MAY-jer
 
KANE-es MY-ner
 
CAP-rih-CORN-us
 
car-EE-na
 
KASS-ee-oh-PEE-ah
 
sen-TOR-us
 
SEE-fee-us
 
SEE-tus
 
kah-ME-lee-un
 
SIR-sin-us
 
ko-LUM-ba
 
CO-ma bare-uh-NYE-sees
 
coe-ROW--nah ow-STRAHL-iss
 
coe-ROW--nah BOR-ee-AL-iss
 
CORE-vuss
 
CRAY-ter
 
Kruks
 
SIG-nus
 
del-FYE-nus
 
doh-RAY-doh
 
DRAY-ko
 
eh-KWOO-lee-us
 
eh-RID-uh-nuss
 
FOR-naks
 
GEM-in-eye
 
GROOS
 
HER-kyou-leez
 
hor-uh-LOW-gee-um
 
HY-druh
 
HY-drus
 
IN-dus
 
la-SIR-ta
 
LEE-oh
 
LEE-oh MY-ner
 
LEE-puss
 
LEE-bra
 
LOUP-us
 
links
 
LIE-rah
 
MEN-sa
 
MY-krow-SKOH-pee-em
 
mon-OSS-er-us
 
MUSS-ka
 
NOR-ma
 
OCK-tens
 
Oaf-ih-YOU-kus
 
oh-RYE-un
 
PAY-vo
 
PEG-uh-suss
 
PURR-see-us
 
FEE-nix
 
PICK-tor
 
PIE-sees
 
PIE-sees oss-TREE-nus
 
PUP-iss
 
PICK-sis
 
reh-TICK-yuh-lum
 
suh-JIT-uh
 
sa-jih-TARE-ee-us
 
SKOR-pee-uss
 
SKULP-tor
 
SCOOT-um
 
SIR-pens CAP-ut
 
SIR-pens KAW-dah
 
SEX-tens
 
TOR-us
 
tell-es-SCOPE-ee-um
 
tri-ANG-yuh-lum
 
tri-ANG-yuh-lum aus-TRAY-lee
 
too-KAY-nah
 
URR-sah MAY-jer
 
URR-sah MY-ner
 
VEE-la
 
VER-go
 
VO-lans
 
vul-PECK-yoo-la

Planets & Moons

 
 
Name
Pronunciation
 
ah-DRAHS-tee-ah
 
et-NEE
 
ah-mal-THEE-ah
 
a-NAN-kee
 
AIR-ee-el
 
AT-lus
 
aw-TON-oe-ee
 
be-LIN-dah
 
bee-AHNK-uh
 
KAL-e-ban
 
ka-LIRR-o-ee
 
ka-LIS-toe
 
ka-LIP-soe
 
KAR-mee
 
kal-DEE-nee
 
CARE-en
 
core-DEAL-ya
 
KRESS-e-da
 
DYE-mos
 
DES-de-MOAN-a
 
de-SPEEN-a
 
dye-ON-ee
 
URTH
 
EE-lahr-ah
 
en-SELL-ah-dus
 
EPP-e-ME-thee-us
 
err-IN-o-mee
 
EE-ris
 
ewe-AN-thee
 
ewe-POUR-ee-e
 
you-ROE-pah
 
ewe-RID-o-mee
 
GAB-ree-ell
 
GAL-aTEA-a
 
GAN-eh-meed
 
har-PAL-e-kee
 
he-LEAN
 
her-MIP-ee
 
HIM-ah-lee-ah
 
hye-PER-ee-on
 
ee-AHP-eh-tus
Io
 
EYE-oh
 
EYE-o-KAS-tee
 
eye-SON-oe-ee
 
JAY-nus
 
JEW-lee-ette
 
JEW-pi-ter
 
KAY-lee
 
KAL-e-kee
 
la-RISS-a
 
LEE-dah
 
lis-ih-THEE-ah
 
MARZ
 
MEG-a-KLYE-tee
 
MIRK-you-ree
 
MEE-tis
 
MYE-mus
 
mi-RAN-dah
 
moon
 
NYE-ad
 
NEP-toon
 
NAIR-ee-id
 
OH-ba-ron
 
oh-FEEL-ya
 
or-THOE-see-e
Pan
 
PAN
 
pan-DOOR-ah
 
pa-SIF-ah-ee
 
PAS-e-thee
 
FOE-bos
 
FEE-bee
 
PLOO-toe
 
POR-sha
 
prak-SID-e-kee
 
pro-MEE-thee-us
 
PRO-per-oe
 
PRO-tee-us
 
PUCK
 
KWA-oh-ar
 
REE-a
 
ROS-a-lind
 
SA-turn
 
SET-e-bus
 
se-NO-pee
 
SPON-dee
 
ste-FAA-noe
Sun
 
sun
 
SICK-o-RACKS
 
tay-IJ-e-tee
 
tah-LES-toe
 
TEE-this
 
tha-LASS-a
 
THEE-bee
 
the-MISS-toe
 
Thy-OE-nee
 
TYE-tun
 
tye-TAIN-ee-ah
 
TRING-kew-loe
 
TRY-ton
 
UM-bree-el
 
YOU-rah-nus
 
VEE-nus

Meteor Showers

 
 
Name
Pronunciation
 
AY-tah AK-wa-rids
 
GEM-e-nids
 
LEE-o-nids
 
LYE-rids
 
north TOR-ids
 
o-RYE-o-nids
 
PUR-see-ids
 
kwa-DRAN-tids
 
south DEL-tah AK-wa-rids
 
south TOR-ids

Stars

 
 
Name
Pronunciation
 
AH-kuh-mar
 
AK-er-nar
 
A--krucks
 
ACK-you-benz
 
ad-HAR-a
 
al-KAP-rah
 
all-NAYR
 
all-NEE-yaht
 
all-soo-HAIL
 
al-BAL-dah
 
al-BEE-ri-oh
 
al-CHIH-ba
 
AL-kor
 
all-SYE--o-nee
 
al-DEB-ah ran
 
al-DER-a-min
 
al-da_FER-a
 
All-firk
 
all-JED-ee
 
al-JEN-nib
 
al-GEE-bah
 
al-GEEB-bah
 
AL-gall
 
ALL-gor-ab
 
al-HAY-nah
 
AL-lee-oth
 
AL-kade
 
al-ka-LOOR-ops
 
ALL-maaz
 
ALL-mahk
 
all-NAH-zul
 
ALL-nil-ahm
 
ALL-nit-ahk
 
AL-fard
 
al-FECK-ah, JEM-a
 
AL-fer-rats
 
all-RAH-kiss
 
all-RESH-ah
 
all-SHAIN
 
AL-tair
 
ALL-tays
 
al-TARF
 
al-TERF
 
 
al-UDE-rah
 
a-LOOL-ah ow-STRAH-liss
 
a-LOOLah bor-ee-AH-liss
 
ALL-zirr
 
UNG-ka
 
ANG-kah
 
an-TAIR-ease
 
arc-TOUR-russ
 
AR-kub
 
AR-kub
 
AR-kub PREE-or
 
AHR-neb
 
ah-SELL-a
 
ah-SELL-us ow-STRALICE
 
ah-SELL-us bore-ee-AL-is
 
ah-SELL-us
 
ah-SELL-us
 
ah-SELL-us
 
ass-mid-ISS-kee
 
ass-pid-ISS-kee
 
AH-tik
 
AT-las
 
AH-tree-a
 
 
AV-i-or
 
AH-za
 
ba-HAHM
 
BARN-ards star
 
BUT-en KYE-tos
 
BYED
 
BEL-la-trix
 
BET-el-jooz
 
boh-TAYN
 
can-OH-pus
 
kah-PELL-ah
 
KAF