If an object name includes a / character, then the menu item Navigation/Select Object does not work. It silently exits without selecting the specified object. The same failure is seen when using the keyboard shortcut "Enter". The HUD "Target name" display goes away but the specified object is not selected.
However, if one uses the "Solar System Browser", such an object name is listed and can be selected there: both Center and GoTo work.
This problem was encountered when trying to specify the comet designation "C/1995 O1" while trying to determine the exact distance between the Horizons and CfA locations for Hale-Bopp. (~54,400KM).
This problem is present in both Celestia v1.2.4 and in v1.2.5pre6.