Occultation of TYC 4668-00680-1 by (1796) Riga on 2011-12-18 Green O+: Henk Bulder Optics: M305 | Method: VIS | Duration: 4.60 6.88,52.94,0 Green O+: John Talbot Optics: M200 | Method: VID | Duration: 6.40 -1.28,51.63,0 Green O+: Tim Haymes Optics: M300 | Method: VID | Duration: 3.44 -0.82,51.51,0 Red O-: Harrie Rutten Optics: M356 | Method: VID | Duration: 6.18,51.48,0 Red O-: R. Simonson et al Optics: M250 | Method: VID | Duration: -0.31,51.43,0