It is located in the western part of Manwoldae in Manwol-dong, Kaesong City.

Originally Chomsongdae was composed of the pedestal made of well-trimmed granites and astronomical instruments on it, but there is only the pedestal at present.

From the early days of its foundation, Koryo Kingdom organized public offices in charge of astronomy and meteorology to make an observation and register the results in detail.

The offices had recorded sunspots more than 50 times from 1105 to the closing days of Koryo Kingdom.

There are also detailed records about peculiar astronomical phenomena like solar eclipse, lunar eclipse, comets and meteors.

And the kingdom had already used five kinds of calendars from the 11th century on the basis of its own astronomical observatory data.