Yonsei University started the astronomy program over 100 years ago, and it was the first of its kind in Korea. Yonsei University Astronomical Observatory was established in 1980, when a 61cm Cass grain reflector was built in the city of Ilsan. Since then, the observatory has played a leading role in observational astronomy, especially in the field of variable stars. The current observatory activities include various public outreach programs and it is one of the major public education facilities offered by the university. In 2000, the observatory launched an ambitious research program for long-term survey astronomy. Since then, the observatory has established three observatory sites abroad, i.e., South Africa, Taiwan and Australia.
- School Observatory: Yonsei Uni Science Hall 7th floor –Cave 40cm reflecting telescope
- Yonsei Observatory Foreign Branches South Africa Sutherland 50cm Pantoscopic survey telescope Taiwan Oksan Observatory 50cm Pantoscopic survey telescope Australia Siding Spring 50cm Pantoscopic survey telescope
- Ilsan Observatory: Gyungido Goyang City Ilsan 6 dong – Goto 61cm reflecting telescope
- Yonsei Radio wave Observatory : Behind Outdoor theater 21m radio wave telescope
- Cheonan Space Observatory: Chungnam Cheonan City Dongmyun Juckgaeri – 50cm Pantoscopic survey telescope, Meade 40cm reflecting telescope
- The facility is open to national/international researchers and Ilsan Observatory has occasional/exceptional tour for students and general audience.