Sternwarteareal, Natural monument and park in Währing, Vienna, Austria

Sternwarteareal is a 5.8 hectare green area with the University of Vienna Observatory at its center, located in the Cottageviertel district. The grounds feature walking paths throughout and display open lawns alongside dense tree coverage.

In the early 1970s the University of Vienna planned a zoology institute on part of the 58,891 m² site, which would have cut 3,615 m² of green space. A residents' initiative opposed it and demanded public access. A May 1973 referendum, the first of its kind in Vienna, rejected the construction with 57.4% of votes; Mayor Felix Slavik resigned and Leopold Gratz succeeded him. The area is now Natural Monument 713.

The name comes from the University of Vienna Observatory at its centre. In May 1973 a referendum on building over the grounds drew 57.4% against construction; mayor Felix Slavik resigned and Leopold Gratz took his place. Since 2 May 2013 marked sections are open to the public on weekdays.

Marked sections of the 58,891 m² grounds have been open to the public on weekdays during the day since 2 May 2013, after a previously closed circular path was reactivated. Access is not possible at weekends, and around 50 trees were felled for the reopening. The site borders the roughly three-times-larger Türkenschanzpark.

The site is listed as Natural Monument 713 in Vienna's register of protected natural monuments. It lies directly beside Türkenschanzpark, which is roughly three times larger. Since 2 May 2013, marked sections have been open to the public on weekdays during the day.