“No, it’s Jupiter!”

Actually, it’s both! The two bright planets move closer together in the western sky after sunset, confusing and bedazzling stargazers all over the world. The two planets are 40 degrees apart at the start of the month, and just 12 degrees apart by month’s end. To tell which is which, remember Venus is always brighter. The Moon brushed past the two bright planets in late January, and will do so again later this month. And the planet Mars is just four weeks from its closest approach to Earth for the next two years.

Here’s what’s happening in the sky this month…

7 Feb. Full Moon (21:54 Universal Coordinated Time)

9 Feb. Mars appears just northeast of a waning gibbous Moon. The Red Planet rises in the early evening and is well positioned to view before midnight.

After hovering in the late-night and early morning sky for the past month, Mars becomes visible in the constellation Leo in the late evening sky. It reaches magnitude -1.2 by month’s end on the way to its closest approach to Earth this year on March 5. This isn’t a great apparition… the planet is not as close as past years… but you can see large surface markings and the polar caps with a small telescope at high magnification.

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Mars and the Moon as seen at 11 p.m. local time February 9, 2012 in the mid-northern hemisphere (click to enlarge)

9 Feb. In a telescope, you can see the tiny disk of Uranus just 1/3 of a degree south of bright Venus.

12, 13 Feb. The Moon passes the bright star Spica and the planet Saturn over these two days in the southeastern sky well after mighnight. Spica shines with a bright white light, and may twinkle a little. Saturn shines with steadier sand-colored glow. Saturn will reach its closest to Earth in mid-April. This month, it’s best seen after midnight.

14 Feb. Last Quarter Moon (17:04 UTC)

21 Feb. New Moon (22:35 UTC)

22 Feb. A very thin 1-day old crescent Moon lies near the bright planet Mercury just after sunset. Use binoculars to see the pair.

Mercury and the 1-day old crescent Moon, as seen on February 22, 2012 after sunset (click to enlarge).

23, 24 Feb. A waxing crescent Moon climbs in the western sky after sunset towards brilliant Venus.

25, 26 Feb.The Moon moves past Venus and towards Jupiter over these two days. Venus is brighter, with magnitude -4.3 this month, while Jupiter shines at magnitude -2.2.  (See image of the two planets at top of page, courtesy Bullit Marquez/AP)

Jupiter, Venus, and the Moon as seen at 7:30 p.m. local time looking west on February 25, 2012 (click to enlarge)

28, 29 Feb. The Moon moves towards the Pleiades and Hyades star clusters.

28 Feb. through March 7. Mercury lies 10 degrees above the western horizon after sunset. This is the best chance to see Mercury in the evening sky this year.

29 Feb. This is a “leap day”, the extra day added to the calendar every four years. Most years have 365 days, but it takes the Earth 365 days, 5 hours, 49 minutes, and 16 seconds to move all the way around the Sun. To keep the calendar aligned to the Sun’s position, we add one full day every four years.  There are no leap days in years divisible by 100, unless the year is divisible by 400.

1 Mar. First Quarter Moon (01:21 UTC)

Gamma Velorum shines at magnitude 1.7. The primary star consists of two unresolvable stars. One is a massive evolved star — a Wolf-Rayet star — that’s shedding mass at a rapid rate. A few million years ago, the star had a mass of 40 suns. Today, it’s slimmed down to “only” 10 solar masses. The escaping hot gas causes the curious spectral signature of this star. This massive star has a close, massive blue O-type companion that revolves around the Wolf-Rayet star once every 79 days.

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The star gamma Velorum (Regor), highlighted in cross-hairs at center (click to enlarge).

About 41″ to the south-southwest lies a 4th-magnitude blue-white star that’s easily resolved in binoculars or small telescope at low power. Recent surveys by the Hipparchos satellite revealed this star is not physically associated with its brighter neighbor. Another 8.5-magnitude companion is visible 62.3” away from the primary. A second double star is located 94” away from the primary. This double is split by just 1.8” and has components with magnitude 9.4 and 13.5.

Gamma Velorum lies 530 light years away.  It’s visible only south of 35°N latitude.

The name of the star, Suhail, causes some confusion because the star lambda Velorum is also called Suhail. But gamma Velorum also has a more modern name. It was coined by astronaut Virgil (Gus) Grissom, the commander of the first Apollo mission. The crew of Apollo 1 planned to use gamma Velorum to help navigate their spacecraft. Grissom jokingly called the star “Regor”, after his crewmate Roger Chaffee (Regor is Roger spelled backwards). After the ghastly accidental fire that claimed the lives of Grissom, Chaffee and their fellow astronaut Edward White on January 27, 1967, the name Regor was informally adopted as the name of this fascinating star system.

Bonus Object: Turn your gaze just 1 degree south of Regor to see the fine T-shaped open cluster NGC 2547. The shape is visible in binoculars, and the cluster opens up nicely in a small telescope. NGC 2547 is sometimes called “St. Peter’s Cross”.

This enigmatic object lies nearly 1º south of iota Orionis at the south end of the Orion Nebula, M42 (see map below).  At 20-30x, the nebula looks like a fuzzy star; at 50-75x, the object looks like a faint star wrapped in icy mist.

Increase magnification to 150x to see the unusual nature of this nebula.  Look carefully for a keyhole-shaped gap in the middle of the reflection nebula itself.  When astronomers first noticed this gap more than a century ago, and others like it (such as the Horsehead Nebula), they believed it was simply a region without stars.  In time, astronomers discovered that most such gaps are not voids, but simply dark clouds of cold dust in the foreground that block out the brighter background material.

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NGC 1999 (in red circles), just south of the Orion Nebula

In 2010, the Herschel Space Observatory, peered into the dark gap of NGC 1999.  Herschel detects infrared light, and can look into dark nebula to see through to the stars within.  But the telescope detected… nothing.  In essence, the telescope verified that this particular dark patch in NGC 1999 is devoid of stars, dust, and any other material.  It really is an empty space.  No one yet knows why, but one theory holds that radiation from new stars within the nebula blast a hole in the surrounding dust.

The image at the top of this page, from the European Space Agency, shows in inset what the nebula looks like in visible light.  The main image shows the nebula as seen by the Herschel telescope, and it shows the keyhole-shaped gap in the upper left.

NGC 2169 is one of a handful of appealing object in the “club” of mighty Orion, above the Hunter’s shoulder marked by the bright orange star Betelgeuse. Look about 5º north-northeast of this star, first to 5th-magnitude μ (mu) Orionis then to the pair of stars ξ (xi) and ν (nu) Orionis. The 6th-magnitude open star cluster NGC 2169 sits just one degree west-southwest of xi (the easternmost star).

At moderate magnification, you’ll see in NGC 2169 about 15-20 stars of 7th magnitude or fainter arranged in two groups, both about 1/10 of a degree across. One group contains 6-7 stars and the other perhaps 10-12 stars. This cluster is sometimes called the “37 Cluster”, because the larger group forms the letter “3” and the smaller group forms the letter “7”. Depending on your optics, the numbers might be flipped left-to-right or upside down, so use your imagination to unscramble the numbers.  See image of the cluster above (credit Noel Carboni, from Astronomy Picture of the Day, Nov. 18, 2005)

NGC 2169 is about 3,400 light years from Earth and is just 8 million years old.

Position of star cluster NGC 2169 in Orion

Much further away, about 12,000 light years, lies the faint open cluster NGC 2194. Find it about 1.6° south-southeast of NGC 2169. In a 4 to 6-inch scope, this appears as a faint icy glow, with few of its brightest stars resolved even at 150x. In an 8-inch or larger scope, the cluster reveals a few more stars along with a silver unresolved background.

NOTE: This article is adapted from the upcoming guide “What To See in a Small Telescope: January-March”, which will be published by One-Minute Astronomer and Stargazer University in early February.

To find Kemble’s Cascade, sweep due east of the W-shaped Cassiopeia a distance equal to the span of the “W” itself, about 10 degrees (the width of your fist held at arm’s length).  The group consists of a 2.5 degree span of some 20 stars in a nearly-straight line running northwest to southeast. The stars are of 7th to 9th magnitude, with a single 5th-magnitude star mid-span.  You need binoculars or a wide-field telescope to see this group.  See the image above to see what to look for (image credit: Walter McDonald).  The asterism lies over the border of Cassiopeia in the constellation Cameloparadalis, the Giraffe.

The open star cluster NGC 1502 lies at the southeastern end of the cascade. This open cluster reveals some 25-30 stars in a triangular pattern in a small telescope at 60-70x.

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This asterism was first noted by Lucien Kemble as he scanned the sky with 7×35 binoculars. Kemble sent his description of this asterism to the great astronomy writer Walter Scott Houston at Sky and Telescope magazine. Houston published Kemble’s remarks in December of 1980, and referred to the group as Kemble’s Cascade from there on.

Lucien Kemble was a respected deep-sky observer in the Royal Astronomical Society of Canada (RASC). In addition to his religious training and duties, Kemble diligently observed the deep sky, recording his observations of more than 5,000 objects with his 11″ telescope under the clear skies of Saskatchewan. Kemble passed away in 1999.

Location of Kemble's Cascade (click to enlarge)

January 1. First Quarter Moon (06:15 Universal Time)

4 Jan. Jupiter’s moons Europa and Ganymede cast simultaneous shadows on the big planet from 6:27 to 7:57 UT. Given the constraints of daylight, this event is best viewed from the Americas. Use a telescope at 100x or more to see this event.

4 Jan. After watching shadows on Jupiter, grab a cup of hot coffee and head back outside to look for the brief but sometimes intense Quadrantids meteor shower between moonset and dawn on the early morning of January 4. The peak shower peaks this year about 07:00 to 08:00 UT, so North Americans will get the best view this year (if the prediction is correct). The shower is quite short… about 2 hours on either side of the peak. Western Europeans may see a few meteors before dawn. The radiant of the shower lies between the handle of the Big Dipper and the head of Draco in the now defunct constellation northern Quadrans Muralis.

4 Jan. Earth passes through perihelion, its closest point to the sun, at a distance of 147,097,907 km

4,5 Jan. The waxing gibbous Moon passes near the Pleiades (on Jan. 4) and the Hyades (on Jan. 5) in the constellation Taurus.

9 Jan. Full Moon (07:30 UT)

16 Jan. Last Quarter Moon (09:08 UT)

19 Jan. The bright star Antares lies just southwest of the crescent Moon in the southwest before dawn.

22 Jan. New Moon (07:39 UT)

22 Jan. Jupiter, which hovers fat and bright overhead all month, reaches quadrature (90 degrees east of the Sun). The planet fades slightly from magnitude -2.4 to -2.1. It also shrinks to an apparent diameter of 39″ (arcseconds) by month’s end. Still worth observing closely with a telescope.

Saturn, Mars, and bright stars Spica and Antares as seen looking south at 5 a.m. on January 25, 2012 at mid-northern latitudes. Southern observers will get a similar view looking nearly overhead. Click to enlarge.

24 Jan. Mars halts its eastward motion and retrogrades westward today. The red-orange planet brightens slightly, but it’s still small at just 12″ by month’s end. The planet reaches opposition on March 3. Some detail is visible now at high magnification in steady sky.

25, 26 Jan. Brilliant Venus is about 8 degrees from the crescent Moon. The bright planet shines at magnitude -4.1 all month in the southwestern sky after sunset.

27 Jan. Saturn rises near midnight. The best time to observe the planet is before dawn this month. The rings are tilted to a generous 15 degrees from edge-on. The planet lies near the bright star Spica in Virgo

31 Jan. Last Quarter Moon (04:10 UT)

First off, this star cluster is NOT dipper-shaped like the Pleiades.  It’s much less regular, with two distinct groupings of stars.  But it resembles the Pleiades in many other ways.

Like M45, many of this cluster’s brightest constituents, including the star theta Carinae itself and the 4th magnitude star V518 Carinae, are easily visible with the naked eye.  In all, the Theta Carinae cluster has about 10 stars brighter than 6th magnitude.

Also like the Pleiades, this cluster is quite young… just 30 million years old.  It’s some 500 light years away versus 450 light years for the Pleiades.  And like M45 it’s 15 light years across.

This cluster, like the Pleiades, is best viewed with binoculars or a wide-field telescope at low power.

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IC 2602, the “Southern Pleiades”, above center

Most of its 60 members are bright blue A and B-type stars, like M45.  But astronomers worked extra hard determining which stars belong to the cluster, and which are merely foreground and background stars in this dense section of the Milky Way.

The cluster, catalogued formally as IC2602, is found in the deep southern skies at RA 10h 43m and Dec -64d24m.  You’ll have a hard time seeing even from Hawaii or India.  For a good look, south of the equator is where you need to be.

Like many southern star clusters, the southern Pleiades were discovered by the diligent French astronomer Louis de Lacaille in 1755 during his star mapping sessions in South Africa.

Bonus Object: There are no shortages of things to see in this stretch of sky.  Just 3/4-degree south of the “Southern Pleiades”, look for another small open cluster called Melotte 101.

European skywatchers must have observed this event also, but they were preoccupied with surviving the Dark Ages and made no record of this supernova. But the Chinese, along with their Japanese and Arabic colleagues, noted the position of this exploding star with enough precision that modern astronomers link this supernova with the “Crab Nebula”, a faint splatter of light easily seen in the constellation Taurus with binoculars or a small telescope.

The Crab Nebula is the first object in Messier’s famous catalog, so it’s commonly known as M1. It’s the only supernova remnant in the catalog. In a small telescope, the nebula appears as an oval splotch about 6′x4′ just one degree northwest of 3rd magnitude zeta Tauri (see map below). This makes it easy to find. At magnitude 8.4, it’s visible in 7×50 binoculars in dark sky. At 30x in a small telescope, the nebula fits in the same field of view as zeta Tauri. At higher-power, the nebula reveals a pinched off region near its centre. The delicate tendrils visible in images are visible only with difficulty in larger telescopes.

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M1, the Crab Nebula, 1 degree NW of zeta Tauri (click to enlarge)

Astronomers know the Crab was created by a core-collapse supernova because the event left a pulsar, a dense city-sized remnant of the stellar core that spins around once every 33 milliseconds. The 16th magnitude pulsar can be seen visually with a 20-inch or larger telescope. But astronomers learn much more about this object through observations at radio and X-ray wavelengths.

Around the pulsar is a dense bubble of material bound by a strong magnetic field. Beyond that is the material ejected by the supernova itself. That’s what you see with your telescope. The remnant continues to expand outward at 1500 km/s, fast enough to notice during a human lifetime. The Hubble Telescope has revealed changes in the outer shell of the Crab Nebula over a few days, which is amazing for an object that’s some 6,000 light years away!  See

Click on image to see animation showing expansion of Crab Nebula (Credit: NOAO)

The nebula takes its name from a drawing made by Lord Rosse in 1844 with a 36-inch telescope at Birr Castle in Ireland. The drawing resembles a horseshoe crab.

Since M1 lies about 1.5 degrees off ecliptic, it’s sometime occulted by the Moon, which helps astronomers map the X-ray emission from the central region of the nebula. The Sun’s corona also passes in front of M1 every June, and the X-rays from the nebula help astronomers infer the physical nature of the corona. Astronomers also used the space-based Chandra X-ray observatory to observe Saturn’s moon Titan passing in front of the Crab. This helped determine the thickness of Titan’s atmosphere.

Observers in Australia, New Zealand, and western North America get a chance to see a total lunar eclipse on December 10. The fine Geminid meteor shower peaks on December 13-14, although the Moon will wash out the faintest meteors.

And the dim stars of October and November finally give way to the mighty constellation Orion as it wheels into view this month in the mid-evening hours. Orion is trailed by brilliant Sirius, the brightest star in the sky, and by the rich star fields of Canis Major and the southern constellation Carina.

Here’s what’s up in the sky this month…

December 2. First Quarter Moon (9:52 Universal Time)

2 Dec. Mars reaches quadrature (90 degrees west of the Sun); the Red Planet reaches the meridian near dawn. It’s growing larger and may reveal a few surface details in a telescope at high magnification.

6 Dec. Bright Jupiter is just to the west of the waxing gibbous Moon.

10 Dec. Full Moon (14:36 UT)

10 Dec. Total Lunar Eclipse, visible in part from western North America (before moonset) and western Europe (at Moon rise). The eclipse is fully visible in Australia and eastern Asia, and almost fully visible in New Zealand. South Africa just glimpses a portion of the eclipse at moonrise. Eastern North America sees a partial eclipse as the Moon sets.

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Mercury and the crescent Moon on December 22, 2011, about 45 minutes before sunrise (click to enlarge)

14 Dec. The Geminid meteor shower peaks at 18:00 Universal Time. Look for meteors on December 13 and 14 anywhere in the sky. They will appear to trace their paths back to a point in Gemini. A gibbous Moon will get in the way of the faintest meteors.

14-28 Dec. Mercury shines brightly about 8-10 degrees above the southeastern horizon about 45 minutes before sunrise.

18 Dec. Last Quarter Moon (00:48 UT)

20 Dec. The waning crescent Moon is near the planet Saturn and the star Spica a few hours before sunrise.

22 Dec. Winter/Summer begins in the Northern/Southern hemisphere (5:30 UT).

22 Dec. A waning crescent Moon is visible near Mercury low in the southeast before sunrise.

Venus and the crescent Moon on December 26, 2011, about 45 minutes after sunset (click to enlarge)

24 Dec. New Moon (18:06 UT)

26 Dec. A thin crescent Moon hovers near brilliant Venus in the southwestern sky just after sunset.

The clusters are easily visible without optics in dark sky as a hazy patch 4 degrees west-northwest of eta Persei (see below).

The Double Cluster was known since antiquity as a faint cloud in the northern Milky Way. William Herschel first discovered the nature of this object. The pair is now cataloged as NGC 884 and NGC 869.

Double Cluster in the northern constellation Perseus (click to enlarge).

Each cluster contains some 300 stars, some of which are immensely bright: 50,000x more luminous than our Sun. These two clusters likely formed out of the same molecular cloud in the Perseus Arm only 3-5 million years ago, making them among the youngest star clusters known. The Pleiades, by comparison, is more than 100 million years old.

Despite their great distance of some 7,000 light years, the two clusters span 1.5-2.0 degrees of sky, so use your lowest-power eyepiece to take them all in. The view in a telescope is truly breathtaking, especially in dark sky. Try to look for colors in these young stars: sapphire blue, topaz, white, and the red glow of swelling giant stars moving towards their violent end as supernovae. When these stars explode, what a sight they will be!

If the Double Cluster were as close as the Pleiades, they would span a quarter of the northern sky. Many of its 600 stars would shine as bright as Vega.

Have a look at the above image, which comes courtesy of Roth Ritter, to see the grandeur of this unique cluster of young stars.