Photometric observations of this asteroid during 2005–06 gave a light curve with a period of 18.075 ± 0.005 hours and a brightness variation of 0.14 in magnitude.[9] In 2009, a photometric study from a different viewing angle was performed at the Organ Mesa Observatory in Las Cruces, New Mexico, yielding a rotation period of 9.036 ± 0.001 with a brightness variation of 0.14 ± 0.02 magnitude. This is exactly half of the 2005–06 result. The author of the earlier study used additional data observation that favored the 9.036 hour period. The discrepancy was deemed a consequence of viewing the asteroid from different longitudes.[6]
^ abPilcher, Frederick (April 2010), "Rotation Period Determination for 53 Kalypso", The Minor Planet Bulletin, 37 (2): 75–76, Bibcode:2010MPBu...37...75P.
^Šidlichovský, M. (1999), Svoren, J.; Pittich, E. M.; Rickman, H. (eds.), "Resonances and chaos in the asteroid belt", Evolution and source regions of asteroids and comets : proceedings of the 173rd colloquium of the International Astronomical Union, held in Tatranska Lomnica, Slovak Republic, August 24–28, 1998, pp. 297–308, Bibcode:1999esra.conf..297S.
^Pray, Donald P.; et al. (December 2006), "Lightcurve analysis of asteroids 53, 698, 1016, 1523, 1950, 4608, 5080 6170, 7760, 8213, 11271, 14257, 15350 and 17509", The Minor Planet Bulletin, 33 (4): 92–95, Bibcode:2006MPBu...33...92P.
