Equuleus, the Pony (Equ)
(eh-QUOO-lee-us)
The Northern constellation of Equuleus, the Pony, is best viewed in Fall during the month of September.
Equuleus is the 87th largest constellation. It's brightest star is Kitalpha at magnitude 3.92. The boundary of the Equuleus constellation contains 3 stars that host known exoplanets.
Equuleus is an equatorial constellation, which means its bulk intersects the celestial equator or comes within 10-15 degrees of doing so. Equuleus is visible from most places on Earth.
- Pronunciation:
- eh-QUOO-lee-us
- Meaning:
- Pony
- Genitive:
- Equulei
- Abbreviation:
- Equ
- Constellation Family:
- Heavenly Waters
- Hemisphere:
- Northern
- Quadrant:
- NQ4
- Visibility:
- 90° N - 80° S
- Best viewing month*:
- September
- Area:
- 72 sq. degrees
- Size:
- 87th largest
- Equatorial:
- Yes
- Right Ascension (avg):
- 21h 15m
- Declination (avg):
- 7°
- Brightest star:
- Kitalpha (3.92)
- Stars with planets:
- 3
- Messier objects:
- |
- Caldwell objects:
- |
Brightest Stars in Equuleus
The 10 brightest stars in the constellation Equuleus by magnitude.
- Star
- Magnitude
- Spectral class
- Alpha Equulei (α Equ)
- 3.92
- G0III+
- Delta Equulei (δ Equ)
- 4.47
- F5V+
- Gamma Equulei (γ Equ)
- 4.7
- F0p
- Beta Equulei (β Equ)
- 5.16
- A3V
- Epsilon Equulei (ε Equ)
- 5.3
- F5III
- Zeta Equulei (ζ Equ)
- 5.63
- K5III
- 9 Equulei (9 Equ)
- 5.81
- M2III
- 4 Equulei (4 Equ)
- 5.94
- F8V
- HD 202951
- 5.97
- K5III
- HD 199942
- 5.98
- A7V
Galaxies in Equuleus
The most notable galaxies in the constellation Equuleus. Also see all galaxies.
The Little Horse Constellation
Equuleus, known as the 'Little Horse,' is a small and faint constellation in the northern sky. Despite its dimness, it has an intriguing history and holds a unique position in the annals of astronomy. It also features fascinating stars that have garnered interest from scientists and astronomy enthusiasts alike.
Historical Background
Equuleus is one of the 48 constellations first listed by the 2nd-century Greek astronomer Ptolemy. It continues to be one of the 88 modern constellations recognized by the International Astronomical Union. Equuleus represents a small horse or foal and is sometimes identified with the offspring of the winged horse Pegasus, from Greek mythology.
Main Features and Location
Located in the fourth quadrant of the Northern hemisphere (NQ4), Equuleus lies between latitudes +90 and -80 degrees. It's bordered by the constellations Aquarius, Delphinus, and Pegasus. Despite its position near the ecliptic plane (the path the Sun appears to take across the sky), it doesn't contain any objects in the solar system that are usually visible from Earth.
Equuleus is the second smallest constellation (only Crux is smaller), covering just 72 square degrees. It's also one of the dimmest constellations, with no star brighter than fourth magnitude.
Significant Stars
The brightest star in Equuleus is Kitalpha, or Alpha Equulei, a binary star composed of two components that are difficult to resolve with small telescopes. The primary is a yellow G-type giant, while the secondary is a white A-type dwarf. Kitalpha is about 190 light years away from us and has a magnitude of 3.9.
Equuleus also hosts some interesting variable stars. Delta Equulei, for example, is an Algol-type eclipsing binary star system, while Gamma Equulei is a fast-spinning white subgiant that completes a rotation in less than a day.
Deep Sky Objects
Due to its small size and relative obscurity, Equuleus contains few notable deep sky objects. It hosts a few faint galaxies such as NGC 7015, NGC 7040, NGC 7046, and NGC 7045, but these are extremely faint and challenging to observe, even with substantial telescopes.
Observation
Equuleus is best observed in September and, despite its dimness, can be seen in full from locations between +90? and -80?. Its position near Pegasus, a larger and more noticeable constellation, can assist observers in locating it.
Due to the constellation's low brightness and lack of standout features, finding and viewing it can pose a significant challenge, particularly for amateur stargazers. Those with a serious interest in astronomy, however, may appreciate the challenge of finding this 'hidden' constellation.
Role in Astronomy's History
While Equuleus may not have played as prominent a role in astronomy's history as some other constellations, it has its unique distinctions. For instance, it's one of the few constellations that ancient astronomers recognized, and it continues to be acknowledged today. Despite its small size and dim stars, Equuleus's resilience over centuries of astronomical observation highlights its subtle but enduring role in our understanding of the cosmos.
* Constellation shown for northen hemisphere skies. For the southern hemisphere, constellations appear rotated 180 degrees (upside-down and left-right reversed) from what is shown. Remember that seasons are reversed too - summer in northern latitudes is winter in southern latitudes.
** Circumpolar constellations are visible year-round in the hemisphere listed (and not at all in the opposite hemisphere).