Head of the Office of Astronomy, took part in making the Cheonsang Yeolcha Bunyajido
| Life | 1320 ~ 1402 |
| Era | 고려·조선 |
| Clan | 서산 류씨 |
Ryu Bang-taek, pen name Geumheon and posthumous name Jeongsuk, was an astronomer who headed the Office of Astronomy in late Goryeo. He is said to have worked with Gwon Geun on the Cheonsang Yeolcha Bunyajido in 1395 and to have been enfeoffed Lord of Seosan for it.
Honored for refusing to serve a second dynasty, he was enshrined at Samungak in Donghaksa on Gyeryongsan in 1621. His son Ryu Baek-yu topped the civil examination in 1369. He is said to have asked that no mound or stele be built on his grave, whose location could not be confirmed. A science museum in Seosan bears his name.