Lat: 53.3°S, Long: 38.8°E, Diam: 89 km, Depth: 3.83 km, Rükl: 75, pre-Nectarian
(IAU Directions) VLACQ.--A member of a magnificent group of closely associated formations situated on the greatly disturbed area between E. long. 30 deg. and 45 deg. and S. lat. 50 deg. and 60 deg. It is 57 miles in diameter, and is enclosed by terraced walls, rising on the E. about 8,000 feet, and on the W. more than 10,000 feet above the floor. They are broken on the S. by a fine crater. In addition to a conspicuous central peak, there are several small craters, and low short ridges in the interior.
- Depth data from Kurt Fisher database
- Westfall, 2000: 3.83 km
- Viscardy, 1985: 3 km
- Cherrington, 1969: 1.18 km
- Central peak composition: A (Tompkins & Pieters, 1999)
- Vlacq and its satellite crater A are on the ALPO list of bright ray craters
- Named for Adriaan Vlacq (1600-1667), a Dutch book publisher and mathematician. Vlacq published a table of Henry Briggs' logarithms from 1 to 100,000 to 10 decimal places in 1628 in his Arithmetica logarithmica.
- According to Whitaker (p. 214), this feature was labeled Pitiscus on Riccioli's map. The usage of the name Vlacq for the present feature was introduced by Mädler, although the same person had been honored earlier by Van Langren (with the spelling Vlacci and the name assigned to the feature now known as Capella) (Whitaker, pp. 219-220).