CBET No. 1716, 2009 March 11 – Central Bureau for Astronomical Telegrams for (4607) Seilandfarm: Photometric observations obtained between 17 January and 25 February 2009, show that 4607 Seilandfarm is a binary system with an orbital period of 31.63±0.02 hours. The primary has a period of 3.9683±0.0001 hours, and it has a lightcurve brightness variation of 0.15 magnitude, indicating a nearly spheroidal shape. Mutual eclipse/occultation events suggest a lower limit on secondary-to-primary mean-diameter ratio of 0.29.Central Bureau for Astronomical Telegrams No. 1716 Reported by: D. Pray, Carbuncle Observatory, W. Brookfield, MA, U.S.A.; P. Kusnirak and P. Pravec, Ondrejov Observatory; J. Gross, W. Cooney, and D. Terrell, Sonoita Research Observatory, Sonoita, AZ; and R. Durkee, Minneapolis, MN.
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Pravec (2009) web: rotation period 3.9683±0.0001 hours with a brightness amplitude of 0.15 mag, as well as Pravec (2014) web: rotation period 3.9681±0.0002 hours with a brightness amplitude of 0.17 mag. Quality Code for both observations: U=3 (denotes a secure result within the precision given and no ambiguity). Summary figures for (4607) Seilandfarm at Collaborative Asteroid Lightcurve Link (CALL)