21. Photometric observations of this asteroid have produced discrepant estimates of the rotation period.22. A recent photometric distance measurement gives an approximate distance of 218 light years. 23. The observatory also has a 38 cm diameter photometric filters and a spectrograph. 24. Several rotational light-curves for this asteroid were obtained from photometric observations. 25. A large number of rotational light-curves were obtained from photometric observations. 26. Several photometric light-curve observations have been performed. 27. In 1877 he began making photometric observations of the planets and their atmospheres. 28. It is a photometric variable with periods of and. 29. These satellites have similar orbits and photometric properties. 30. They used photometric methods to obtain new values for the luminosity of the Cepheids.