Cetus
looking toward
S190°
ALT 31° · FOV 94°
🌟ByulGil
observatory
Seoul
37°33′N · 126°58′E
2026.10.22 17:50
LIVE · 25 OF 40 ABOVE
Tonight's Sky
40 CONSTELLATIONS
constellation

Cetus

고래자리
The sea monster · The Whale
Autumn · hard to observe in May
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Science
The science

Cetus is the fourth-largest constellation in the sky, representing the mythical sea monster Cetus. Its star Mira (Omicron Ceti) was the first "periodic variable star" humanity ever discovered, its name meaning "the wonderful" in Latin. An aging red giant, it rises and falls in brightness over a cycle of about 332 days, from 2nd magnitude (plainly visible to the naked eye) to 10th magnitude (seen only through a telescope) — a change of hundreds of times over. Its star Tau Ceti, closely resembling the Sun and lying just 12 light-years from Earth, has long been a prime target in the search for a "second Earth" and for extraterrestrial life.

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Mythology
The myth

Cetus is the sea monster that threatened Ethiopia. Sent by Poseidon, god of the sea, in his anger at Queen Cassiopeia's arrogance, the monster swept the coasts and plunged the kingdom into terror, and an oracle demanded Princess Andromeda as a sacrifice. Just as Andromeda, chained to a seaside rock, was about to be swallowed, the hero Perseus appeared on his way back from slaying Medusa and turned the monster to stone with Medusa's head. Even this fallen sea monster rose into the sky, taking its place beside the autumn royal constellations it had once threatened.

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Stars
Main stars (equatorial)
MenkarRA 3.04h · Dec 4.1° · m2.5
KaffaljidhmaRA 2.72h · Dec 3.2° · m3.5
MiraRA 2.32h · Dec -3.0° · m3.0
Baten KaitosRA 1.76h · Dec -10.3° · m3.7
Tau CetiRA 1.73h · Dec -15.9° · m3.5
DiphdaRA 0.73h · Dec -18.0° · m2.0
IotaRA 0.32h · Dec -8.8° · m3.6
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Созвездия над вами прямо сейчас

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Ночное небо в реальном времени

Карта созвездий ночного неба в реальном времени

Какие созвездия сейчас у вас над головой, меняется от мгновения к мгновению — в зависимости от времени, даты и вашего местоположения. Пока Земля вращается, звёзды восходят на востоке и заходят на западе; пока Земля обращается вокруг Солнца, видимые созвездия меняются с временами года. Byulgil вычисляет это реальное небо по астрономическим данным J2000.0 и рисует созвездия, видимые из вашего местоположения прямо сейчас, в виде живой карты и в режиме AR. Ничего не нужно устанавливать — просто откройте браузер и посмотрите на сегодняшнее небо.

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Byulgil is a stargazing web app that computes the real night sky for your location, anywhere in the world, in real time. Byulgil means "Star Loads", in Korean. Use your current location (GPS) or pick a major city — Seoul, Tokyo, New York, Sydney — to see the sky exactly as it appears there, right now. Star positions come from real J2000.0 equatorial coordinates, converted to horizontal coordinates for your time and place. On mobile, AR mode lets you point your phone at the sky to overlay the constellations in that direction.