[9] Altdorfer is a member of the Flora family, one of the largest groups of stony asteroids in the main-belt.
[7] According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Altdorfer measures 2.5 kilometers in diameter and its surface has a high albedo of 0.35,[4][5] while the Collaborative Asteroid Lightcurve Link assumes an albedo of 0.24 – derived from the family's principal body and namesake, the asteroid 8 Flora – and calculates a diameter of 2.1 kilometers with an absolute magnitude of 15.59.
[3] A rotational lightcurve of Altdorfer was obtained through photometric observations taken at the Palomar Transient Factory in January 2012.
Lightcurve analysis gave a rotation period of 4.0221 hours with a brightness variation of 0.34 magnitude (U=2).
Altdorfer was also an architect of the city of Regensburg, Germany, after which the minor planet 927 Ratisbona is named, and was also a significant printmaker, with numerous (copper) engravings and woodcuts.