On September NUMBER@1 , NUMBER@2 , Titania occulted a bright star -LRB- HIP106829 -RRB- with a visible magnitude of NUMBER@3 ; this was an opportunity to both refine the moon 's diameter and ephemeris , and to detect any extant atmosphere .

Occultation On September NUMBER@1 , NUMBER@2 , Titania occulted a faint star ; this was a chance to both refine its diameter and ephemeris , and to detect any extant atmosphere .
