Vulpecula, the Fox, is a faint northern constellation located within the famous Summer Triangle, between the bright stars Vega, Deneb, and Altair. Although its stars are relatively inconspicuous, Vulpecula contains some remarkable astronomical objects, including the Dumbbell Nebula (M27), the Coathanger asterism, and the first pulsar ever discovered.
Covering approximately 268 square degrees, Vulpecula is the 55th-largest of the 88 recognized constellations. Its position along the Milky Way makes it an interesting region to explore with binoculars and telescopes, particularly during summer and early autumn.
Where and When to Find Vulpecula
Vulpecula is best observed from the Northern Hemisphere between July and October, when the Summer Triangle is prominent in the evening sky. The constellation lies south of Cygnus, north of Sagitta, and close to Aquila.
To locate it, first identify the Summer Triangle, formed by Vega in Lyra, Deneb in Cygnus, and Altair in Aquila. Vulpecula occupies part of the region between Deneb and Altair, beneath the Northern Cross. Unlike neighboring Cygnus, Vulpecula has no striking naked-eye star pattern. Its brightest stars are only around fourth magnitude, so a dark sky and a star chart are helpful when identifying the constellation. However, its position within the Milky Way makes it particularly rewarding to explore with binoculars.
History and Mythology
Unlike many ancient constellations, Vulpecula has no traditional Greek or Roman mythology. It was introduced by the Polish astronomer Johannes Hevelius in 1687 under the name Vulpecula cum Ansere, meaning “the Little Fox with the Goose.” Hevelius imagined a fox carrying a goose toward the nearby constellation Cerberus, representing the three-headed dog that guarded the entrance to the Underworld. Both the goose and Cerberus eventually disappeared as separate constellation figures, leaving Vulpecula as the Fox. The constellation’s brightest star, Anser, preserves the memory of the original goose.
Notable Stars
- Anser (Alpha Vulpeculae) is the brightest star in Vulpecula, a red giant shining at magnitude +4.4 from approximately 300 light-years away. Its name means “goose” in Latin, recalling the constellation’s original name. It appears close to the orange giant 8 Vulpeculae, forming an attractive optical double star.
- 23 Vulpeculae is an orange giant shining at approximately magnitude +4.5. It is one of the constellation’s brightest stars, although it is not particularly conspicuous without dark skies.
- 13 Vulpeculae is a blue-white evolved star shining at around magnitude +4.6, making it another of Vulpecula’s brighter naked-eye stars.
- 31 Vulpeculae is a yellow giant with an apparent magnitude of approximately +4.6. Like several other stars in the constellation, it is easier to identify using a chart than by following an obvious star pattern.
The First Pulsar Ever Discovered
One of Vulpecula’s most important astronomical objects is PSR B1919+21, the first pulsar ever discovered.
In 1967, graduate student Jocelyn Bell Burnell detected a series of remarkably regular radio pulses while examining observations from a radio telescope at Cambridge University. The signals arrived approximately every 1.337 seconds. Their extraordinary regularity initially prompted joking speculation about an extraterrestrial source, earning the signal the nickname “Little Green Men 1.”
Further investigation showed that the pulses came from a rapidly rotating neutron star, the dense remnant of a massive star that had undergone a supernova explosion. The discovery opened an entirely new field of astronomy. Antony Hewish, Bell Burnell’s supervisor, shared the 1974 Nobel Prize in Physics with Martin Ryle, although Bell Burnell was not included in the award.
Notable Deep-Sky Objects
Dumbbell Nebula (M27)
The Dumbbell Nebula (Messier 27, NGC 6853) is Vulpecula’s most famous deep-sky object and one of the brightest planetary nebulae visible from Earth. Located approximately 1,200–1,400 light-years away, it shines at around magnitude +7.5 and covers a relatively large area of sky. Despite its name, a planetary nebula has nothing to do with planets. It forms when an aging star sheds its outer layers into space, leaving behind a hot stellar core whose ultraviolet radiation causes the expelled gas to glow.
M27 was discovered by Charles Messier in 1764 and became the first object of its kind to be recognized as a planetary nebula. Its distinctive two-lobed appearance resembles a dumbbell or an apple core, although long-exposure photographs reveal a much larger and more complex structure.
How to find it: Locate the small arrow-shaped constellation Sagitta just south of Vulpecula. From Gamma Sagittae, the star marking the arrow’s tip, move approximately three degrees north to reach M27.
Under dark skies, the nebula can appear as a faint, fuzzy patch through binoculars. A small telescope reveals its characteristic shape, while a larger instrument and a suitable nebula filter can bring out additional detail.
The Coathanger Asterism (Collinder 399)
The Coathanger, also known as Brocchi’s Cluster or Collinder 399, is one of the most recognizable binocular star patterns in the summer sky. Its brightest stars form a remarkably convincing upside-down coat hanger, complete with a hook and horizontal bar.
Although once cataloged as an open star cluster, modern measurements show that most of its stars are not physically associated. The Coathanger is therefore an asterism, rather than a true star cluster. It lies near the border with Sagitta and is best appreciated through binoculars, which provide a wide enough field of view to show the entire pattern.
NGC 6823 and NGC 6820
NGC 6823 is a young open star cluster embedded in a rich region of the Milky Way. Nearby lies NGC 6820, an emission nebula associated with the same star-forming region. Astrophotographs reveal glowing hydrogen gas, dark dust clouds, and pillars of material shaped by radiation from young massive stars.
Other deep-sky objects in Vulpecula include the open cluster NGC 6885 and the distant elliptical galaxy NGC 7052.
Observing Vulpecula
Vulpecula is an excellent example of a constellation whose most interesting objects are far more impressive than its stars.
Begin by finding the Summer Triangle, then use Sagitta as a guide to the Dumbbell Nebula. Binoculars are ideal for exploring the Coathanger, while a small telescope provides rewarding views of M27.
For observers exploring the summer Milky Way, Vulpecula offers a worthwhile detour between the brighter constellations of Cygnus and Aquila.