Horologium

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For the giant sundial built by Augustus, see Solarium Augusti.
Horologium
Constellation
Horologium
Abbreviation Hor
Genitive Horologii
Pronunciation /ˌhɒrɵˈlɒiəm/,
genitive /ˌhɒrɵˈlɒi/
Symbolism the Pendulum Clock
Right ascension 3
Declination −60
Family La Caille
Quadrant SQ1
Area 249 sq. deg. (58th)
Main stars 6
Bayer/Flamsteed
stars
10
Stars with planets 2
Stars brighter than 3.00m 0
Stars within 10.00 pc (32.62 ly) 1
Brightest star α Hor (3.85m)
Nearest star GJ 1061
(11.99 ly, 3.66 pc)
Messier objects none
Meteor showers ?????
?????
Bordering
constellations
Eridanus
Hydrus
Reticulum
Dorado
Caelum
Visible at latitudes between +30° and −90°.
Best visible at 21:00 (9 p.m.) during the month of December.

Horologium is a small and faint constellation in the southern sky (declination around −60 degrees). Its name is a Latin transliteration of the Greek [1] word for clock (Horo [ὥρο]- meaning hour and logium [λέγειν] meaning teller [horologium= the hour-teller]).

History[edit]

Horologium was plotted in the 18th century by Abbé Nicolas Louis de Lacaille.[2] He originally labeled it Horologium Oscillitorium, the Latin name for a pendulum clock, to honour its inventor Christiaan Huygens and his book Horologium Oscillatorium.

Notable features[edit]

The constellation Horologium as it can be seen by the naked eye

Stars[edit]

Horologium does not have any bright stars. Alpha Horologii, the brightest, is an orange giant of magnitude 3.9, 117 light-years from Earth. Beta Horologii is a white giant of magnitude 5.0, 314 light-years from Earth. However, Horologium does have several variable stars. R Horologii is a red giant Mira variable with a very wide range, 1000 light-years from Earth. It has a minimum magnitude of 14.3 and a maximum magnitude of 4.7; its period is approximately 13 months.[2]

Deep-sky objects[edit]

Horologium is also home to many deep-sky objects; there are several globular clusters in the constellation. NGC 1261 is a globular cluster of magnitude 8, 44,000 light-years from Earth.[2] The globular cluster Arp-Madore 1 is found in the constellation, the most remotely known globular cluster in the Milky Way at a distance of 398,000 light years.

See also[edit]

References[edit]

  1. ^ Smith, William (1875). A Dictionary of Greek and Roman Antiquities. London: John Murray. pp. 615‑617. 
  2. ^ a b c Ridpath & Tirion 2001, pp. 156-157.

External links[edit]

Coordinates: Sky map 03h 00m 00s, −60° 00′ 00″