Double Stars

Maserthim (γ Arietis)

Maserthim (γ Arietis)

: By Glenn Chaple
I’m a double star aficionado; my sky gazing motto is “double stars are twice the fun!” Unlike the “faint fuzzies” most backyard astronomers prefer, double stars aren’t hidden by light pollution or bright moonlight. They aren’t the exclusive property of big-scope owners. In fact, many showpiece doubles are within reach of small-aperture instruments. The common 60mm refractor with its crisp stellar images delivers exquisite views of double stars - especially twin systems.

Struve 2816 and 2819: Triple and Double Stars in Cepheus

: By Glenn Chaple
There’s something hypnotic about a double star – two gleaming points of light shining bravely through the surrounding darkness. A triple star is even more mesmerizing. Place a double star and triple star in the same eyepiece field, and the visual effect is stunning. This is what greets the eye when you view the triple/double star combo Struve 2816 and Struve 2819.
Porrima: Binary Star in Virgo

Porrima: Binary Star in Virgo

: By Glenn Chaple
Compiling a list of the finest double stars for backyard telescopes is always a work in progress. The list is forever in flux, because many showpiece double stars are binary systems that periodically close to the point where they can’t be resolved by small-aperture telescopes. Such is the case with Porrima (gamma [γ] Virginis).
Algieba: Double Star in Leo

Algieba: Double Star in Leo

: By Glenn Chaple
One of the finest double stars in the spring sky – indeed, in all the heavens – is gamma (y) Leonis. Its proper name, Algieba, comes from the Arabic Al Jabbah (The Lion’s Mane).

Almach

: By Glenn Chaple
Last month, I suggested that our featured object, Albireo, may not be the most beautiful double star in the sky and I’d introduce a rival this month. If you guessed that Albireo’s challenger is Almach, the gamma (?) star in Andromeda, you’d be correct!
β Scorpii

β Scorpii

: By Glenn Chaple
This month, we travel southward to the constellation Scorpius and the showpiece double star beta (β) Scorpii, also known as Graffias. Beta Scorpii is an eye-pleasing pair of magnitude 2.6 and 4.5 stars separated by 13.6 arc-seconds. The magnitudes and separation are quite similar to those of the better-know Mizar; indeed, Graffias rivals Mizar in visual splendor.

Castor: alpha (α) Geminorum

: By Glenn Chaple
Are you looking for something new and different to add to your late winter/early spring star party repertoire – a cosmic showpiece guaranteed to elicit a gasp of surprise and wonder from anyone who peers into your telescope? I suggest the double star alpha (α) Geminorum, better know as Castor. One glance at these sparkling magnitude 2.0 and 2.9 diamonds and it’s easy to understand why William Herschel’s son, John, considered Castor the finest double star in the northern sky.

β Monocerotis

: By Glenn Chaple
Observe one of the sky's best triple stars just 12 degrees east of the Great Orion Nebula.

Izar (ε Boötis)

: By Glenn Chaple
A larger telescope and magnifying power of 200X will readily split Izar and reveal a striking color contrast between the golden yellow primary and its bluish companion. The Russian astronomer Wilhelm Struve, who conducted a double star survey in the late 1820s and early 1830s, nick-named it “Pulcherrima” (The Most Beautiful).

M40: The “Unknown” Messier Object

: By Glenn Chaple
Arguably the oddest member of the Catalog, M40 isn’t a cluster, nebula, or galaxy. It’s a double star! We might well label M40 “Messier’s Mistake.”

h 3945 Canis Majoris

: By Glenn Chaple
What is the most colorful double star in the night sky? Most amateur astronomers would vote for β Cygni (Albireo). Others might cite γ Andromedae (Almach), ι Cancri, ξ Bootis, or η Cassiopeiae. Sadly overlooked is a double star that might challenge them all – h 3945 in Canis Major. It is arguably the most colorful double star in the winter sky and, in fact, has been nick-named the “Winter Albireo.”

Beta Orionis (Rigel)

: By Glenn Chaple
You won’t need a finder chart to locate this month’s featured sky object. It’s the first magnitude star β Orionis, better known by its proper name Rigel. Seventh brightest star in the night sky, Rigel dazzles us with a diamond-white color; especially striking when compared with Orion’s other first-magnitude star, the ruddy-hued Betelgeuse.

Epsilon Pegasi: The Pendulum Star

: By Glenn Chaple
Epsilon Pegasi (Enif) is an optical double star comprised of magnitude 2.5 and 8.7 component stars separated by 144 seconds of arc. Pairs this wide usually don’t merit much consideration, but wait! Epsilon Pegasi has a surprise for us.

Chaple’s Arc

: By Glenn Chaple
Forgive me for the apparent ego trip, but this month I’m going to introduce you to an amazing little asterism called “Chaple’s Arc.” I stumbled upon the Arc in the mid-1970s while looking for the double star h1470.

44 Boötis

: By Glenn Chaple
44 Boötis, whose 210-year orbit is highly inclined to our line-of-sight, has opened up. Its magnitude 5.3 and 6.2 component stars are separated by 2.2 arc-seconds.
Mizar, The First Double Star

Mizar, The First Double Star

: By Glenn Chaple
The middle star in the handle of the Big Dipper, Mizar is the easiest double star for the novice to locate. It boasts historical importance as the first double star discovered.

Struve 817 Orionis

: By Glenn Chaple
I’m a big fan of “off-the-beaten-path” sky objects. One of my favorites is the little-known double star Struve 817 - the 817th double star catalogued by the German-born Russian astronomer F. G. W. Struve during a survey conducted between 1824 and 1827.

A Selection of Double Stars in Andromeda

: By Glenn Chaple
Andromeda is home to a fine collection of double stars. Here are eight of the best. Data on magnitudes and separation were taken from the Washington Double Star Catalog.

A Selection of Double Stars in Draco

: By Glenn Chaple
A hazy summer evening may prevent you from observing nebulae and galaxies, but it could afford ideal seeing conditions for high power targets like double stars.

A Selection of Double Stars in Cancer

: By Glenn Chaple
For our spring double star selection, we’ll say goodbye to Gemini and shift eastward to the faint constellation Cancer. Notable for its bright Messier cluster M44 (the Praesepe), Cancer is also home to a splendid array of double and multiple stars. How many can you notch? (Data from the Washington Double Star Catalog (WDS)

A Selection of Double Stars in Gemini

: By Glenn Chaple
It’s appropriate that the constellation Gemini, the Twins, should be home to a numerous collection of double stars. Here are ten stellar – pardon the pun - examples (data from the Washington Double Star Catalog (WDS).

A Selection of Double Stars in Scorpius

: By Glenn Chaple
Our summer double star adventure takes us to the southern skies and the constellation Scorpius. The region north and west of, and including, Antares contains a remarkable array of showpiece double and multiple stars.

A Selection of Double Stars in Corona Borealis

: By Glenn Chaple
It’s time to come out of hibernation! After two months of intense cold weather here in the Northeast, mild temperatures are returning. Celebrate spring with a visit to one of the season’s loveliest constellations, Corona Borealis. The Northern Crown is home to a splendid collection of double stars. Here are ten of the most noteworthy.
A Selection of Double Stars in Boötes

A Selection of Double Stars in Boötes

: By Glenn Chaple
During the warm summer evenings, the constellation Boötes is perched high in the sky after sunset. The Herdsman is a rich hunting ground for double stars.

Some Bright Spring Double Stars

: By Glenn Chaple
To most deep sky enthusiasts, spring means “galaxies.” Hundreds of these island universes – many in the Coma-Virgo cluster – are within the reach of backyard scopes. Often forgotten are the beautiful double stars that also inhabit the spring skies. Here are ten of the best:

Some Bright Winter Double Stars

: By Glenn Chaple
The winter night sky, dominated by mighty Orion, is rich with deep-sky splendors. If you can brave the cold, you’ll be rewarded by some of the finest double and triple stars the night sky has to offer.

Some Bright Autumn Double Stars

: By Glenn Chaple
Autumn is a season of promise for the stargazers. The nights are getting longer, the air clearer, and those pesky summer mosquitoes are a thing of the past. In a few months, Orion and his magnificent wintry retinue will take center stage. While the autumn night sky appears devoid of bright stars, it’s still home to a rich array of double stars. Here are ten of the best:

Some Bright Summer Double Stars

: By Glenn Chaple
In this modern era of the huge galaxy-gulping Dobsonian reflector, double stars have become the neglected children of the cosmos. That’s too bad, because few heavenly objects have the visual appeal of double stars.

Summer Double Stars

: By Nan D'Antuono
The same hazy summer skies that provide excellent views of the planets also bring many double stars within reach of the small-scope user, some of which are close pairs. Here are just a few of these stars, waiting to be observed before the Square of Pegasus rises to announce that fall is but three months away.

Spring Double Stars: The Three Leaps of the Gazelle

: By Nan D'Antuono
The Great Bear Ursa Major is high in the north these Spring evenings. Along his southwestern border, shared with the constellations Lynx, Leo Minor, and Leo lie the three distinctive pairs of third magnitude stars known from ancient times by many names, one of the best known of which is the charming name "The Three Leaps of the Gazelle." Three of the six leap stars are wonderful doubles, and there are many more awaiting discovery in Ursa Major.