Category Archives: Skywatch Line

This is Dudley Observatory’s Skywatch Line for Friday, April 19 through Sunday, April 21, written by Sam Salem.

On Friday, the Sun rises at 6:08am and sets at 7:42pm; the full Moon occurs at 7:12am; Moon rises at 8:04pm and sets at 6:36am.

Look to the west as evening twilight begins to fade to see Mars, at magnitude 1.6, in constellation Taurus. Mars is noticeably fainter than Aldebaran, Taurus’ brightest star. Both Mars and Aldebaran glow with the same pale orange hue. Mars sets around 11:30pm. Jupiter, at magnitude –2.4, rises around midnight. Jupiter shines fairly high in the south before the beginning of dawn. This is the best time to observe the planet. Set up your scope about two hours before sunrise. At that time you’ll find Antares to Jupiter’s lower right, and the dimmer Sagittarius Teapot a similar distance to Jupiter’s lower left. The Teapot is about the size of your fist at arm’s length. Saturn, at magnitude 0.6, rises around 2am. Saturn is the brightest dot in eastern constellation Sagittarius. Saturn glows pale yellow-white, about 25 degrees to Jupiter’s left or lower left. Venus, at magnitude –3.9, pops up in the east, one hour before sunrise. Easy to miss, is nearby Mercury, which rises just 45 minutes before the Sun.

Saturn now climbs high enough in the dawn sky to potentially offer some enjoyable views. The ideal time to observe Saturn is roughly 5am when the ringed planet is approaching its greatest altitude before twilight becomes overwhelmingly bright. Saturn lies around 20 degrees above the southern horizon at that time. For this low altitude of 20 degrees, the telescopic view will usually be compromised by turbulent seeing conditions. With the ring system currently tilted open almost the maximum amount, you should have little trouble spotting the famous Cassini Division, a 4,700 kilometer wide gap that separates Saturn’s two brightest rings. Under good seeing conditions, this feature is visible even in a small telescope.

Lyrid meteor shower is expected to put forth the most meteors during the predawn hours on Monday and Tuesday. The annual Lyrid meteor shower is active each year from about April 16 to 25. As with most meteor showers, the peak viewing time will be before dawn. That’s when the radiant point, near the star Vega in the constellation Lyra, is highest in the sky. Unfortunately, the waning gibbous Moon, very close to full, will wash out all but the very brightest meteors this year during the peak.

Some religious holidays are scheduled based on the Moon’s phases. Passover and Easter, celebrated this weekend, are scheduled according to full Moon. Passover is celebrated on the first full Moon after the spring equinox. Easter falls on the Sunday that follows the first full Moon occurring on, or, the day after the spring equinox. If the full Moon occurs on a Sunday, Easter is observed the following Sunday. On the other hand, the first day of Ramadan, to be celebrated in a couple of weeks, is scheduled based on the new Moon.

This is the Dudley Observatory Skywatch Line for Wednesday, April 17th, and Thursday, April 18th, written by Louis Suarato.

The 97% illuminated, waxing gibbous Moon rises at 5:48 p.m. on Wednesday. At astronomical twilight, when the Sun is 12 to 18 degrees below the horizon, the Moon can be seen surrounded by the stars of the constellation Virgo. Virgo is the second largest constellation, covering 1,294 square degrees. This constellation is most prominent in the evening skies from March through July. Virgo’s brightest star is Spica, the 16th brightest in the sky. Spica is not only bright because of its close proximity, about 260 light-years away, but it is also a binary system with the larger star twice as large as our Sun. Spica also marks the southern point of the Spring asterism known as the ”Great Diamond”, or, the “Virgin’s Diamond”. Clockwise from Spica, the other stars in this asterism are Arcturus in Bootes, Cor Caroliin Canes Venatici, and Denebola in Leo. Many nearby galaxies occupy the Great Diamond, including those of the Virgo Supercluster. There are approximately 1,500 galaxies within this group, the brightest being Messier 49. Explore this area within the Great Diamond with your telescope on a moonless night.

Mars is lower over the western horizon in the constellation Taurus after sunset these nights. Look to the lower right of Mars for the Pleiades star cluster. Jupiter rises 13 minutes after midnight, followed by Saturn about 2 hours later. Venus rises at 8 minutes after 5 a.m., followed by Mercury 15 minutes later. Venus and Mercury will be separated by 5 degrees. Both may be too close to sunrise to observe.

The Albany Area Amateur Astronomers invites you to join them for their monthly meeting to be held at miSci in Schenectady beginning Thursday evening, March 18th, at 7:30.. This month’s talk will be about America’s mission to the Moon. This is the 50th anniversary of Apollo 11’s landing on the Moon. The talk will further discuss efforts to discuss lunar exploration since then. The talk will conclude with a summary of future ideas and plans to explore the Moon.

This is the Skywatch Line for Monday and Tuesday, April 15th and 16th.

The Sun sets at 7:37 PM; night falls at 9:20. Dawn begins at 4:30 AM and ends with the Sun rising at 6:12.

The 11-day-old Moon dominates the evening sky. Monday, it lies in Leo, near the lion’s rear leg, appearing about 85% illuminated, blazes with minus 11th magnitude and 43º high in the South. Tuesday, the Moon moves into Virgo and appears fuller and a bit brighter. Monday, the Moon is highest at 10:10 PM and sets at 5:02 AM on Tuesday. Tuesday night, the Moon is best observed at 11:04 PM and set at 5:34 AM on Wednesday.

Mars is now the sole evening planet. It inhabits Taurus, appears about 95% lit and shines with 1st magnitude 36º high in the southwest. Mars sets at 11:30 PM.

This is also a good night to note the passing of winter constellations and the rise of spring and summer star patterns. Orion and Taurus set about 10:00 PM. Cancer, Leo, Hydra, Virgo are already quite prominent. Midnight witnesses the rise of Hercules, Lyra and Scorpius.

Jupiter rises in Ophiuchus at 12:22 AM and is best observed at 4:53 AM. A telescopic observer can see the Great Red Spot, a giant storm, at 1:12 AM on Tuesday.

Saturn, in Sagittarius, rises at 2:08 AM, about 26º to Jupiter’s lower left. It shines with zero magnitude and appears about half Jupiter’s size.

Neptune and Venus share Aquarius. Neptune rises at 4:53 AM, glowing with 8th magnitude and appearing a tiny 2 arc-seconds in size. Finding Neptune will be a challenge in the rapidly brightening sky, so an observer should try as early as possible. Venus rises at 5:11 AM, blazes with minus 4th magnitude and appears about 85% lit.

Saturn, by Dawn, is already up and high in the southeastern sky. The cream-colored planet is obvious in the dim constellation of Sagittarius. Besides the rings, Saturn has sixty-one moons. One of these, Iapetus, has puzzled observers for centuries. Iapetus is bright when it is on one side of Saturn, but markedly darker when on the other.

Recently, two groups of astronomers think they have figured it out. Iapetus is tidally locked to Saturn, just like the Earth’s Moon – showing the same side to the planet. The leading side of Iapetus sweeps up debris from a newly discovered (and invisible to amateurs) ring. Thus, one side looks like it was covered in chocolate dust, while the trailing side is as white as snow, really ice. In addition, the dust, warmed by sunlight, melts the ice below, which flows to the trailing side and re-freezes. Iapetus has a 79.3-day orbit, and is visible in amateur telescopes. Astronomy programs and websites assist the observer.

This is Dudley Observatory’s Skywatch Line for Friday, April 12 through Sunday, April 14, written by Sam Salem.

On Friday, the Sun rises at 6:20 and sets at 7:34pm; the first Quarter Moon occurs at 3:06pm; Moon sets at 2:07am and rises at 11:67am. On Saturday, the waxing gibbous Moon can guide you to the location of constellation Cancer, the Crab. Constellation Cancer is very faint. You won’t see it well in the moonlight. Regulus, the brightest star in the constellation Leo, the Lion, shines on one side of Cancer, while the Gemini stars, Castor and Pollux, shine on the other side. Take note of the position of these three stars relative to the Moon. Then, on a dark night, when the Moon has dropped out of the evening sky, use Regulus, Castor and Pollux to locate Cancer, the Crab. Cancer’s brightest star is magnitude 3.5, meaning that none of Cancer’s stars can be seen from light-polluted cities or suburbs. On a moonless night and a dark sky, use binoculars to see a cluster of stars within Cancer, called Praesepe, also known as the open star cluster Messier 44, most frequently called the Beehive. On Sunday night the Moon will move closer to Regulus.

All five naked-eye planets are currently visible. Try to locate Mars in the early evening as it sits 7 degrees to the right of Aldebaran, the brightest star in constellation Taurus. Mars, at magnitude 1.5, is drifting eastward through Taurus, slowly gaining elevation as it climbs towards the ecliptic’s most northerly point, in constellation Gemini. Mars sets shortly after 11:30pm. Jupiter, at magnitude –2.3, rises shortly before 1am. Jupiter culminates at roughly 5am. Saturn clears the east-southeast horizon shortly before 2:30am. Saturn, at magnitude 0.5, sits in eastern constellation Sagittarius and outshines all the stars in the region. As dawn approaches, Venus, at magnitude –3.9, rises less than one hour before the Sun. It can be seen easily in bright twilight. Slightly lower and a few degrees to the left of Venus is Mercury. The innermost planet is mid-way through its least favorable morning showing for this year, you’ll have a much better chance to catch it at dusk in mid-June.

On Friday night, you have a good opportunity to investigate the Straight Wall, one of the Moon’s most interesting formations. The Straight Wall, also known by its Latin name, Rupes Recta, appears as a narrow black line etched onto the lunar surface when viewed shortly after first-quarter phase. Rupes Recta is a linear fault on the Moon, in the southeastern part of the Mare Nubium. It is a dividing line between two sections of terrain that have shifted relative to one another. A vertical shift has produced an apparent cliff. When the Sun illuminates the feature at an oblique angle at about the eighth day of the Moon’s orbit, the Rupes Recta casts a wide shadow that gives it the appearance of a steep cliff. Although it appears to be a vertical cliff in the lunar surface, the grade of the slope is relatively shallow. The fault has a length of 110 km, a typical width of 2–3 km, and a height of 240–300 meters.

This is the Dudley Observatory Skywatch Line for Wednesday, April 10th, and Thursday, April 11th, written by Louis Suarato.

The 27% illuminated, waxing crescent Moon rises at 9:48 Wednesday morning. Nightfall finds the Moon below the feet of the Gemini twins, and above the horns of Taurus the bull. Look for Mars to the lower right of the Moon leading the way to the northwestern horizon. In March, the Mars rover, Curiosity, captured two amazing solar eclipses of the moons Phobos and Deimos, as seen from the martian surface. Neither Phobos, which is 16 miles in diameter, nor Deimos, 10 miles in diameter, are large enough to totally eclipse the Sun. Curiosity also captured the elongated shadows cast by Phobos while the Sun was on the horizon.

Jupiter rises at 12:41 a.m. Thursday in Ophiuchus, 6 degrees to the right of the open star cluster, M23. M23, also known as NGC 6494, was discovered by Charles Messier on June 20, 1764. This open cluster is 2,050 light-years away, and estimated to contain 169 to 414 stars about 330 million years old. M23 can be seen through binoculars or small telescopes. Saturn rises at 2:27 a.m. in Sagittarius. Venus rises at 5:16 Thursday morning, followed by Mercury 15 minutes later. Mercury reaches aphelion, its furthest distance from the Sun on Wednesday, and reaches its greatest western elongation from the Sun, at 28 degrees, on Thursday.

How dark are your skies? Under ideal conditions, the unaided eye can see stars with an average magnitude of 6.5. It is estimated there are about 8,479 stars within that magnitude limit. Given that about half of these stars would be below the horizon, you can probably see close to 2,500 stars with the naked eye under perfectly dark and clear conditions, such as a moonless night. In an extremely light-polluted city like New York, that number drops down to about 15. A quick way to determine the observing quality of your skies is to use the constellation Ursa Minor as a benchmark. Ursa Minor is the home of Polaris, the North Star, and the Little Dipper asterism. The stars comprising the bowl of the Little Dipper are magnitude 2, 3, 4, and 5. If you can see all these stars, your skies are considered very good for observing. If you can only see Polaris and the two stars on the handle of the Little Dipper, known as the Guardians, then the quality of your sky is considered fair to poor.

This is the Skywatch Line for Monday and Tuesday, April 8th and 9th.

The Sun sets at 7:29 PM; night falls at 9:09. Dawn begins at 4:44 AM and ends with the Sun rising at 6:24.

The 3-day-old Monday’s Moon dominates the southwestern sky. In Taurus, it appears about 13% illuminated, blazes with minus 6th magnitude and is about 30º high at Civil Dusk. Tuesday’s Moon also resides in Taurus, is brighter, fatter and higher. The Moon sets at 11 PM on Monday, and at 12:05 AM on Wednesday.

Mars shares Taurus with the Moon. It appears about 94% lit, about 4 arc-seconds in size and glows with 1st magnitude. Mars sets at 11:34 PM.

Uranus, in Aries, challenges the observer. It glows with 6th magnitude, but is 3 arc-seconds in size and about 6º low in the West. The observer should work quickly to find it amid the rapidly diving planet, which sets at 8:33 PM.

The Midnight sky is temporarily devoid of planets, but houses two challenging objects for observers. The first is the asteroid 2 Pallas, in Bootes and the second asteroid to be discovered. Heinrich Olbers, of Germany, found it on March 3rd 1802, while looking for Ceres, the first identified asteroid. He knew it was a body close to Earth because it moved significantly in a matter of hours. Other astronomers determined it was the same distance as Ceres, orbits the Sun every 4.62 years, and about 500 kilometers in size. This was the first hint of what we call the Asteroid Belt between Mars and Jupiter. 2 Pallas rises at 6:26 PM and is best observed 1:43 AM. It is located in Bootes, very close to the star Murphid and glows with 8th magnitude; it reaches Opposition at 9 PM, Tuesday.

Not too far from 2 Pallas is the 7 Iris, another telescopic asteroid. In Corvus, it glows at 9th magnitude, but is a tiny 0.1 arc-seconds in size and is about 33º high in the South. It is located very close the star Delta Corvi. It rises at 7:12 PM, is best observed at 12:32 AM and sets at 5:43 AM. Finder charts for both bodies can be found from various astronomical websites.

Dawn skies are full of bright planets. Jupiter, in Ophiuchus, sparkles at minus 2nd magnitude, about 40 arc-seconds in size and 24º high. It rises at 12:49 AM and is best viewed at 5:21 AM. Wednesday, telescopic observers can see the moon Io disappear at 2:21 AM and its sister moon Europa disappear at 3:55 AM. The Great Red Spot, a giant storm, is visible at 5:39 AM, in the brightening sky.

Saturn, 26º below Jupiter in Sagittarius, rises at 2:35 AM and shines with zero magnitude, appearing about half Jupiter’s size and 17º high in the eastern Dawn.

Venus shares Aquarius with Neptune, very low on the eastern horizon. Both rise almost simultaneously at 5:20 AM. Venus, blazing with minus 4th magnitude appears about 83% lit. Neptune is less than 1º above Venus but is a much dimmer 8th magnitude. Both are only 6º degrees high in the brightening sky. Binoculars are recommended.

Like planets and comets, asteroids have defined orbits about the Sun. Comets are ice and rock mixes, while asteroids are mostly rock. Comets sport tails behind them, the result of ices evaporating in sunlight. Asteroids appear as dim dots in a telescope. There are several types of asteroid. Some orbit between Jupiter and Mars; others accompany planets; and then there are inhabitants of the far reaches of the solar system. Some of these distant asteroids are redefined as “dwarf planets.” The largest “dwarf planet” is Eris, which is larger and more massive than Pluto.

This is Dudley Observatory’s Skywatch Line for Friday, April 5 through Sunday, April 7, written by Sam Salem.

On Friday, the Sun rises at 6:31am and sets at 7:26pm; the new Moon occurs at 4:50am. On Saturday, the Moon will be over one day old after sunset. If you have a clear and unobstructed horizon in the direction of sunset, you have a good chance of catching the whisker-thin young Moon after sunset. Young moons in early spring are usually much easier to catch than young moons in early autumn. That’s because the ecliptic, the approximate monthly pathway of the Moon and planets, hits the sunset horizon at a steep angle in spring yet a shallow angle in autumn. Day by day, a wider waxing crescent will shine higher up in the sky at nightfall.

Mars, at magnitude 1.5, hanging around in evening twilight, is making its way eastward through constellation Taurus. Jupiter, at magnitude –2.3, rises in the southeast, in southern Ophiuchus around 1am. Jupiter is at its best for telescopic view when it culminates around 6am in bright twilight. Trailing Jupiter is Saturn, at magnitude 0.6, which is up shortly before 3am. Saturn is climbing higher each week. Last up is Venus, at magnitude –3.9. It clears the horizon a little before 5:30am, and climbs to low altitude of about 10 degrees by sunrise. Venus is at the mid-way point of a lengthy morning apparition that began at the end of October and continues into next August.

For the first time, astronomers and scientists detailed their findings about the mini-moons nestled between Saturn’s rings that NASA’s Cassini spacecraft skimmed past in 2017. The mini-moons, Pan, Daphnis, Atlas, Pandora and Epimetheus, each measure between five to 72 miles in diameter. They are either round, shaped like flying saucers, or resemble potatoes. They are wedged in the gaps separating Saturn’s rings. The study published last week in the US Journal Science, reinforces the dominant theory that Saturn’s rings and moons stem from the same celestial body, which shattered as a result of some kind of collision.

This moonless weekend is an opportunity for some galaxy observing. The Leo Trio of galaxies consists of the spiral galaxies M65, M66 and the edge-on spiral NGC3628. These three wonderful galaxies can be seen in one small cluster in the constellation of Leo. In the early evening, constellation Leo is high in the south. M66 is the brightest of the three. M65 is more cigar-shaped making it harder to spot, and NGC 3628 is the hardest to observe. You’ll need a dark sky to see all three. The location of the Leo Triplett is easy to find. Start at 3.3 magnitude Theta (θ) Leonis. Then, head south-southeast about 3 degrees. M65 and M66 are the brightest of the three, at magnitudes 10.1 and 9.6, respectively. You will need a telescope to be able to glimpse at the 10.4 magnitude NGC3628.

On April 6, 1955, detection of radio emissions from the planet Jupiter was reported at the semi-annual meeting of the American Astronomical Society in Princeton, N.J. Astronomers, Bernard Burke and Kenneth Franklin, at the Carnegie Institution in Washington, had discovered waves that resembled short bursts of static, similar to the interference on home radios caused by lightning. This was the first time radio waves were detected from any planet in our solar system. It took several weeks to pinpoint Jupiter as the origin of radio emissions.

This is the Dudley Observatory Skywatch Line for Wednesday, April 3rd, and Thursday, April 4th, written by Louis Suarato.

The 2% illuminated, waning crescent Moon sets at 5:42 p.m. Wednesday. The Moon will rise again less than 1% illuminated at 6:39 Thursday morning. Look over the western horizon at astronomical twilight, at 9:01 p.m., when the Sun is12 to 18 degrees below the horizon, for Mars between the constellation Taurus’ brightest star, Aldebaran, and the Pleiades star cluster. Aldebaran is a red giant star that is the fourteenth brightest in our sky, and about 65 light-years from our Sun. Jupiter and Saturn flank Sagittarius in the pre-dawn sky. The two interior planets, Mercury and Venus appear to be headed toward the Sun as they lead Earth in their solar orbits. Mercury orbits the Sun at 112,000 miles per hour and Venus orbits the Sun at 78,337 miles per hour. Both planets may be too close to the Sun to see before sunrise.

On August 1, 2016, the Solar and Heliospheric Observatory (SOHO), captured the final moments of a comet racing toward the Sun at 1.34 million miles per hour. That object remains the fastest object in our solar system. The fastest known objects in the universe are known as blazars. Blazars are active galactic nuclei composed of ionized matter traveling close to the speed of light, or about 670 million miles per hour.

There will be an extremely bright International Space Station pass over our region Thursday night. Look over the west-northwestern horizon beginning at 9:06 pm. This 3.1 magnitude ISS pass will continue through the constellation Perseus, and pass over the Big Dipper before disappearing into Earth’s shadow.

Take advantage of the moonless nights to view one of the most eye-pleasing celestial objects, globular cluster M5. Discovered by Gottfried Kirch in 1702, M2 can be found above the southeastern horizon, below Arcturus in the constellation Serpens around midnight. Densely packed with 100,000 to 500,000 stars, M2 is approximately 13 billion years old, and 24,500 light-years away. It is one of the oldest globular clusters in the Milky Way galaxy.

This is the Skywatch Line for Monday and Tuesday, April 1st and 2nd.

The Sun sets at 7:21 PM; night falls at 8:59. Dawn begins at 4:58 AM and ends with the Sun rising at 6:36.

Mars continues as the only easily visible planet in our evening sky. In Taurus, the Red Planet is about 94% illuminated, shines with first magnitude and appears as a 4 arc-second red dot. At Civil Dusk, it is 39º high and sets at 11:38 PM.

Uranus, in Aries, lies 30º to Mars’ lower right, about 12º above the western horizon. It shines with 6th magnitude and is visible as a 3 arc-second blue orb. It sets at 8:59 PM.

Dawn brings a new set of bright planets. Jupiter, in Ophiuchus, is the first to rise at 1:16 AM. The giant planet shines with minus 2nd magnitude and is a large 40 arc-seconds in apparent size; it is highest at 5:48 AM. At Dawn, Jupiter is about 23º high, permitting views of its Galilean Moons and features. On Tuesday, at 3:28 AM the Moon Io’s shadow begins to cross the planet’s face, at 4:38 Io itself follows, at 5:36 Io’s shadow exits the planet. The Great Red Spot, a giant storm on Jupiter, is best observed at 5:28 AM, Wednesday.

Saturn rises in Sagittarius at 3:02 AM. It glows with zero magnitude and appears about half of Jupiter’s size and about 16º above the eastern horizon. It is high enough for observation of its famous rings shortly before 6 AM.

Aquarius is crowded with bright planets and the Moon. Venus is the third to rise at 5:26 AM. It is about 82% lit in our instruments, blazes at minus 4th magnitude but is only 6º high by Civil Dawn.

Neptune and Mercury, also in Aquarius, rise almost simultaneously. In fact, they form a quasi-conjunction, which means that they are not in a true conjunction, but less than 5º apart. Mercury rises at 5:44 AM and appears 31% lit, shines with zero magnitude, and is 9 arc-seconds in size. Neptune flickers with 8th magnitude and is a tiny 2 arc-seconds in size. Binoculars and unobstructed view are recommended.

Finally, the Moon makes its appearance at 5:46 AM on Tuesday. It is about 8% lit, blazing with minus 4th magnitude. Tuesday morning shows it about 3º below Venus. Wednesday, a thinner sliver of Moon shines with minus 2nd magnitude and rises at 6:13 AM. The Moon’s low altitude also requires binoculars and a clear horizon.

As soon as people began looking at the night sky with telescopes, they encountered cloud-like objects. They were called “nebulae,” Latin for “clouds.” Charles Messier, an 18th Century comet hunter, was annoyed by these nebulae and listed them, so he would not confuse them with comets. As telescopes and techniques improved, astronomers discovered that many nebulae were spiral in appearance. In the early 20th Century, giant telescopes revealed these spirals to be immense swarms of stars. Later, astronomers discovered that these swarms were not part of our own locale, but distinct and distant “island universes”, which they called “galaxies.” Later, astronomers discovered that galaxies travelled in clusters. Our Milky Way galaxy is one of about 2000 similar island universes which make up the Virgo Galaxy Cluster.

The Virgo Cluster is visible in our skies from nightfall until Dawn. It inhabits the empty space between Leo’s tail, Virgo’s Head, and Coma Berenices. The Virgo Cluster is composed of about 2000 galaxies which are about 55 Million Light Years distant. A small telescope can see about 100 on a good night. The galaxy M87 appears be the cluster’s center.

This is Dudley Observatory’s Skywatch Line for Friday, March 29 through Sunday, March 31, written by Sam Salem.

On Friday, the Sun rises at 6:44am and sets at 7:18pm; the waning crescent Moon rises at 3:27am and sets at 12:54pm. On Friday morning, the Moon lies roughly three degrees to the lower left of Saturn, as the pair rise together shortly before 3:30am. In late March and early April, the waning crescent Moon will be sweeping past Venus. The pair will be gracing the eastern sky, an hour or so before sunrise. Even after all the stars have disappeared in the glow of twilight, the Moon and Venus will remain visible.

For several evenings, Mars will be near the Pleiades cluster, in constellation Taurus, in western sky at nightfall. Mars is closest to the cluster on Sunday night, when it’s positioned roughly three degrees east of the cluster’s center.

Jupiter, at magnitude –2.2, rises around 1:30am in the southeast, in southern constellation Ophiuchus. Saturn, at magnitude 0.6, is up before the Sun and sits east of the Teapot asterism in constellation Sagittarius. Saturn is much fainter than either Jupiter or Venus. You’ll want to catch Saturn before the dawn light becomes too overpowering. Venus, at magnitude –4.0, clears the south-southeast horizon around 5:30am.

This weekend, take the opportunity of the moon-free evenings to explore deep-sky wonders of constellation Cancer, the celestial crab. Start with the open cluster M44, also known as the Beehive Cluster. M44 is a fine binocular object that’s easy to locate. The one-degree-wide clump of stars is parked midway and a little west of a line joining Delta (δ) and Gamma (γ) Cancri. At magnitude 3.9, Delta is Cancer’s brightest star. Another delightful open cluster is M67. Under a dark sky the little stellar gathering is visible in steadily held binoculars as a fuzzy patch. M67 looks much better in a telescope at moderate magnification. The constellation Cancer is also home to a number of fine double stars, including Iota (ι) Cancri. Iota is a striking sight in small telescopes. It features a 4.1-magnitude yellow star contrasting with a 6.0-magnitude blue companion, separated by 31 arc-seconds. The two are easily split in any scope used at low power.

On March 29 1974, Mariner 10 took the first close-up pictures of Mercury. On its way to Mercury, Mariner 10 made its first flyby of Venus on February 5 1974 and discovered evidence of rotating clouds. The mission was the first spacecraft to use the gravitational pull of one planet to help it reach another planet. In three flybys past Mercury, it mapped about half of Mercury’s surface. It found a thin atmosphere and a magnetic field. Mariner 10 was also the first to use the solar wind as a means of locomotion. When the probe’s thruster fuel ran low, scientists used the solar panels as sails to make course corrections.

This Saturday, at 8.30PM, local time, is “Earth Hour”. The world’s largest grassroots movement for the environment continues to unite millions of people around the world who take part in this annual celebration. Earth Hour 2019, with its campaign ‘#Connect2Earth’, aims to build mass awareness on why nature is important and create a movement for nature similar to when the world came together to tackle climate change. Join millions around the world to turn off the lights and speak up about why nature matters. Visit Earth Hour website for more information. https://www.earthhour.org