The Geomagnetism Program has operated an observatory at Puerto Rico since 1903. The current observatory site, consisting of 36 acres in the mountains near Cayey, has been in use since 1965.
![San Juan Observatory sign](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/side_image/public/thumbnails/image/SanJuan_sign.jpg?itok=KFDdpv6y)
Station Id: SJG
Location: Cayey, PR
Latitude: 18.1110°N
Longitude: 66.1498°W
Geomagnetic Latitude: 27.62°N*
Geomagnetic Longitude: 6.95°E*
Elevation: 424 meters
Orientation: HDZF
* IGRF values as of 2015.
Other Operations:
- A seismometer for the USGS Global Seismic Network.
- A seismometer for the Puerto Rican Seismic Network.
- CTBTO IMS Auxiliary Seismic Station
- NOAA National Centers for Environmental Information (NCEI) ionosonde
Photos:
![San Juan magnetic observatory.](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/side_image/public/thumbnails/image/Cayey_third_size.jpg?itok=4XPMOvfb)
![Absolutes, variations and proton buildings (left to right) at San Juan magnetic observatory, Cayey, Puerto Rico.](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/side_image/public/thumbnails/image/Cayey2_third_size.jpg?itok=IN27iauE)
The Geomagnetism Program has operated an observatory at Puerto Rico since 1903. The current observatory site, consisting of 36 acres in the mountains near Cayey, has been in use since 1965.
![San Juan Observatory sign](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/side_image/public/thumbnails/image/SanJuan_sign.jpg?itok=KFDdpv6y)
Station Id: SJG
Location: Cayey, PR
Latitude: 18.1110°N
Longitude: 66.1498°W
Geomagnetic Latitude: 27.62°N*
Geomagnetic Longitude: 6.95°E*
Elevation: 424 meters
Orientation: HDZF
* IGRF values as of 2015.
Other Operations:
- A seismometer for the USGS Global Seismic Network.
- A seismometer for the Puerto Rican Seismic Network.
- CTBTO IMS Auxiliary Seismic Station
- NOAA National Centers for Environmental Information (NCEI) ionosonde
Photos:
![San Juan magnetic observatory.](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/side_image/public/thumbnails/image/Cayey_third_size.jpg?itok=4XPMOvfb)
![Absolutes, variations and proton buildings (left to right) at San Juan magnetic observatory, Cayey, Puerto Rico.](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/side_image/public/thumbnails/image/Cayey2_third_size.jpg?itok=IN27iauE)