Snare a dozen double stars and deep-sky objects in the celestial Hare. Also, find out how to watch the potentially hazardous asteroid Apophis occult a star on February 21st.
It's easy to ignore Lepus, the Hare. He crouches beneath Orion's feet as if trying not to draw attention. Don't let him hide from you. There's a lot to see here in small and modest instruments, including winter's brightest globular cluster, tasty flavors of double stars, and one of the reddest suns in the sky. Ignore Orion for a night. Instead, chase the hare to see what you may have been missing.
In early February, Lepus culminates in the south around 8 p.m. local standard time. The Moon will brighten the sky later this week, but dark skies return again on March 2nd. My observations were made with a 15-inch Dobsonian reflector, but all our featured objects are visible in a 6-inch reflector and several in binoculars. North is up in all maps and images except where noted.
R Leporis always gets a reaction. It's just so obviously RED. And there's something about a red star that excites the imagination. Discovered by British astronomer J. R. Hind in 1845, he nailed the description of the star as a "drop of blood on a black field." Located 1,400 light-years away, Hind's Crimson Star is one of the closer carbon stars, a special subset of Mira-type variable stars with atmospheres rich in carbon. Carbon absorbs blue light from the star's spectrum, turning it a rich shade of red.
R Lep's magnitude varies over a period of 445 days from as bright as 5.5 to as faint as 11.7. Its color changes, too, from deep red around minimum (typically 9.5–10 magnitude) to coppery at maximum.
As of mid-February, the star shines around magnitude 7.8 as it slowly sinks to minimum, making it an easy and colorful target even in a 3-inch telescope. My eyes see cherry Kool-Aid. How would you describe its hue? For a detailed chart and light curves, visit the American Association of Variable Star Observers (AAVSO) site.
Stars with Partners
Lepus has more pretty, small-scope double stars than you can shake a carrot at. Several are bright, easy pairs for all telescopes, but a few pose welcome challenges for 6-inch and larger scopes because they combine relatively close separations with a large magnitude difference between the primary and secondary. Save these for nights when the stars sit still.
Double star separations and position angles are current and taken from the Washington Double Star Catalog. Basic data for each star is given in parentheses: magnitude of the primary and secondary, separation, and position angle.
S473 (7 + 8.5, 20.6″, 307°): The "S" stands for James South, a British astronomer who worked with John Herschel in the early 19th century to produce a catalog of 380 double stars, then struck out on his own to find 458 more. His #473 is an easy pair for small scopes with two bright components and a comfortable separation.
S476 (6.3 + 6.5, 39″, 19°): One of my favorite leporine pairs. Two white, equally bright pearls immediately get your attention at low magnification — a super-easy duo in any scope. For a challenge, try splitting them in binoculars. As long as I kept my pair of 8×40s steady both stars were plainly visible . . . but very close!
Gamma (γ) Leporis (3.6 + 6.3, 96″, 349°): Before you swing your telescope to this one, look first in binoculars. This bright, unequal double cleaves easily into close-set, dual jewels even at 7×. The large separation may make you wonder if this is a true physical pair. Indeed they are, as both suns share a common proper motion. At at distance of 29 light-years their true separation is about 128 billion kilometers.
h3752 (AB pair — 5.4 + 6.6, 3.5″, 91° and AC pair — 5.4 + 9.3, 60″, 104°): A gorgeous triple star discovered by John Herschel located a little more than ½° southwest of the globular cluster M79. John got the small "h," while doubles found by his father, William, bear a capital "H."
At low magnification you'll first notice the widely separated primary and tertiary, but crank up the power to 150× and the primary star undergoes celestial mitosis to become a beautiful, close pair. The brightest of the three appears pale yellow, the others colorless to my eye.
h3750 (4.7 + 8.5, 4.0″, 279°): Disparate magnitudes and frequent, choppy air at this declination (–25°) made this unequal double difficult to divide. But with patience and a magnification of 245× I occasionally discerned the secondary as a tiny flicker of light nearly due west of the primary.
Beta (β) Leporis (2.9 + 7.5, 2.7″, 10°): Even more challenging than h3750, this close pair is oh-so-satisfying in good seeing at 200× and up. The magnitude difference is extreme, which made seeing the tiny companion star so frightfully close to its brilliant brother a moment of real observing excitement.
Kappa (κ) Leporis (4.4 + 6.8, 2.2″, 357°): Despite my best efforts I couldn't confirm separating this close, unequal pair. I suspect the 2.2″ separation (measured in 2008) has since narrowed, making this an even more challenging object. Winter skies are rarely steady where I live, but I'm certain that observers with 4-inch or larger telescopes at more southerly latitudes will do better. Please let us know if you split it!
M79 (magnitude 8.2, diameter 9.6′): When you need a globular fix on mid-winter evenings, this is your only easy choice. M79 is a moderately bright, very compact cluster with a dense core surrounded by an expansive halo of faint, approximately 14th magnitude suns. A single 12th magnitude star (member?) appears almost due north of the center. With 142× and averted vision the halo is well resolved into faint stars, but the innermost core — a near-stellar, fuzzy knot — resists resolution even at magnifications in excess of 300×.
M79 is one of the few globular clusters visible on the opposite side of the sky from the galactic center. When you bring it to focus in the eyepiece, try to imagine you're looking far below the plane and outside the edge of the Milky Way 41,000 light-years away.
Some astronomers think our galaxy poached M79 from the Canis Major Dwarf Galaxy. Tidal interactions have stretched the former dwarf into a ring of related star clusters (including M79) that wraps around the Milky Way. The greatest concentration of stars is just 25,000 light-years away, making the shredded dwarf the closest external galaxy to Earth. Soon it will lose its identity altogether as the Milky Way slowly devours its contents. Life just isn't fair.
NGC 2017 (magnitude 6.4, diameter 10′): Some sources describe this object as a sparse open cluster. Others indicate it might be an asterism (Star Clusters, Brent Archinal and Steven Hynes), while the Washington Double Star Catalog lists it as the complex multiple star h3780! Will the real NGC 2017 please stand up?
I see a compact group of four bright and several fainter stars in a Y-shaped arrangement located 1.5° east of 3rd-magnitude Alpha (α) Leporis. The four brightest stand out boldly at low magnification in any telescope with the southernmost member appearing distinctly orange. I also spotted two fainter magnitude-10 and -11 stars (G and I) within the figure and a much more difficult seventh star of 14th magnitude due south of A.
Observers with better seeing and 8-inch or larger instruments can try splitting the 8.9-magnitude star labeled C in the photo. Its 9.6-magnitude companion, D, lies 1.5″ away in P.A. 356°. Want a tougher test? The brightest star, A, is a tight double with the separate designation, Bu 321. Can you crowbar away its 7.8-magnitude companion located just 0.5″ at P.A. 160°?
IC 418 (magnitude 9.3, diameter 12″): My favorite painted egg in the Lepus bunny basket. Tiny but bright, it looks like a fuzzy, bluish star at first sight. To truly appreciate what you're seeing, max out the magnification: 428× and 571× gave fantastic views of the blue-tinted 10.5-magnitude central star embedded within a pale blue ovoid tipped northwest-southeast. Some observers report that the nebula's outer ring glows subtly red, but I couldn't see this.
With averted vision I occasionally glimpsed a darker gap between the bright inner nebula and the periphery, as well as hints of the flecked texture revealed in Hubble images that give this planetary its nickname, the Spirograph Nebula. A spirograph is a toy used to draw multiple overlapping geometric curves called hypotrochoids and epitrochoids.
IC 418 is a relatively young planetary nebula about 0.3 light-years across located approximately 5,000 light-years away. Ultraviolet light from the white dwarf at its center ionizes gases sloughed off previously by the star during its red giant phase.
NGC 1964 (magnitude 10.8, size 5.6′ × 1.8′): The Hare's brightest galaxy, NGC 1964, is located 1.7° southeast of Beta (β) Leporis. With multiple arms, a fat bar in the center, and diameter of 100,000 light-years, it could almost be a stand-in for our own Milky Way.
Three 10.5-magnitude stars arranged in a compact acute triangle will direct you straight to the galaxy. At 64× I immediately spotted the bright, near-stellar nucleus centered within a bright inner disk but had to increase the magnification and use averted vision to make out the fainter outer disk extending northeast-southwest from the nucleus.
While I detected no trace of spiral structure, two faint stars superimposed on the galaxy allowed for a moment's fantasy of discovering dual supernovae. A 13.5-magnitude star shines 45″ west of the core and and one of 14.5 magnitude ~ 1.5′ to the northwest. Beware!
Alessi 64 (magnitude ~9, diameter 7.5′): Discovered by Brazilian amateur Bruno Alessi, this modest object is considered an open cluster candidate. I tried but was unable to find many details about it, so it's possible the group is a chance alignment of stars. But at least to my eye it looks like the real thing. A roughly equilateral triangle of two magnitude-10.5 and one magnitude-11 star caught my eye at 64×. Additional fainter stars within and around the figure, including a faint, 2′-wide, smoky glow of very faint members immediately south of the triangle's northern apex, added up to about 25 stars in all.
The most famous potentially hazardous asteroid — 99942 Apophis — will occult the magnitude 7.0 star HD 89707 (= HIP 50671 = SAO 155919) on the night of February 21st (February 22nd UT) visible from the U.S. between 5:45 and 5:55 UT. The star is located in Hydra at right ascension 10h20m50″, declination –15°48′41″.
Apophis currently has a 1 in 150,000 chance of crashing into the Earth in April 2068. Because the asteroid is only about 370 meters across, the maximum duration of the occultation will be around 0.1 second. Apophis will be just a 17th-magnitude speck, but it covers a 7th-magnitude star, so a video recording should be able to capture the disappearance.
While a challenge to observe and record, amateurs are strongly encouraged to observe the occultation. Careful timings of the disappearance and reappearance of the star from multiple locations will nail down Apophis's orbital motion. This will help astronomers better account for non-gravitational forces such as the Yarkovsky Effect that could affect the asteroid's future close approaches to our planet.