|Symbolism||the Pendulum Clock|
|Area||249 sq. deg. (58th)|
|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)
|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  word for clock (Horo [ὥρο]- meaning hour and logium [λέγειν] meaning teller [horologium= the hour-teller]).
Horologium was plotted in the 18th century by Abbé Nicolas Louis de Lacaille. He originally labeled it Horologium Oscillitorium, the Latin name for a pendulum clock, to honour its inventor Christiaan Huygens and his book Horologium Oscillatorium.
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.
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. 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.
- Ridpath, Ian; Tirion, Wil (2001), Stars and Planets Guide, Princeton University Press, ISBN 0-691-08913-2
- Ian Ridpath and Wil Tirion (2007). Stars and Planets Guide, Collins, London. ISBN 978-0-00-725120-9. Princeton University Press, Princeton. ISBN 978-0-691-13556-4.
|Wikimedia Commons has media related to Horologium.|
- The Deep Photographic Guide to the Constellations: Horologium
- Starry Night Photography - Horologium Constellation
- Star Tales – Horologium
- Horologium Constellation at Constellation Guide