Horologium
Encyclopedia
Horologium is a small and faint constellation
in the southern sky (declination
around −60 degrees). Its name is Latin
for clock
. It was created in the 18th century by Abbé Nicolas Louis de Lacaille, who originally named it Horologium Oscillitorium after the pendulum clock
to honour its inventor, Christiaan Huygens. The name has since been shortened to be less cumbersome.
One of the few objects of interest to amateur observers is R Horologii
, a Mira variable
with one of the largest magnitude ranges known. The globular cluster
AM1 is found in the constellation, the most remotely known globular cluster in the Milky Way
at a distance of 398 000 light years.
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
in the southern sky (declination
Declination
In astronomy, declination is one of the two coordinates of the equatorial coordinate system, the other being either right ascension or hour angle. Declination in astronomy is comparable to geographic latitude, but projected onto the celestial sphere. Declination is measured in degrees north and...
around −60 degrees). Its name is Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
for clock
Clock
A clock is an instrument used to indicate, keep, and co-ordinate time. The word clock is derived ultimately from the Celtic words clagan and clocca meaning "bell". A silent instrument missing such a mechanism has traditionally been known as a timepiece...
. It was created in the 18th century by Abbé Nicolas Louis de Lacaille, who originally named it Horologium Oscillitorium after the pendulum clock
Pendulum clock
A pendulum clock is a clock that uses a pendulum, a swinging weight, as its timekeeping element. The advantage of a pendulum for timekeeping is that it is a resonant device; it swings back and forth in a precise time interval dependent on its length, and resists swinging at other rates...
to honour its inventor, Christiaan Huygens. The name has since been shortened to be less cumbersome.
One of the few objects of interest to amateur observers is R Horologii
R Horologii
R Horologii is a red giant star approximately 100 light-years away in the constellation Horologium. It is also a Mira variable with a period of 407.6 days, and has one of the largest magnitude ranges known .- External links :* *...
, a Mira variable
Mira variable
Mira variables , named after the star Mira, are a class of pulsating variable stars characterized by very red colors, pulsation periods longer than 100 days, and light amplitudes greater than one magnitude in infrared and 2.5 magnitude in visual...
with one of the largest magnitude ranges known. The globular cluster
Globular cluster
A globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes and relatively high stellar densities toward their centers. The name of this category of star cluster is...
AM1 is found in the constellation, the most remotely known globular cluster in the Milky Way
Milky Way
The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...
at a distance of 398 000 light years.
External links
- The Deep Photographic Guide to the Constellations: Horologium
- Starry Night Photography - Horologium Constellation
- Star Tales – Horologium