Vallis Snellius [SEP] located on astronomical body
Vallis Snellius
Vallis Snellius is a linear valley on the near side of the Moon. It is located in the rugged southeastern part of the visible surface, to the south of the Mare Fecunditatis. This feature is radial to the Mare Nectaris basin to the west-northwest, much like Vallis Rheita to the southwest, and the two likely share a common origin. The selenographic coordinates of this feature are , and it has a maximum length of 592 km, making it the longest named valley on the Moon.
Leiden Observatory
Leiden Observatory () is an astronomical institute of Leiden University, in the Netherlands. Established in 1633 to house the quadrant of Rudolph Snellius, it is the oldest operating university observatory in the world, with the only older still existing observatory being the Vatican Observatory.
The observatory was initially located on the university building in the centre of Leiden before a new observatory building and dome were constructed in the university's botanical garden in 1860. It remained there until 1974 when the department moved to the science campus north