Time-Resolved Optical Observations of PSR 1509-58
  Using time resolved 2-dimensional aperture photometry we have established that the optical candidate for PSR 1509-58 does not pulse. Our pulsed upper limits (m_V = 24.3 and m_B = 25.7) put severe constraints on this being the optical counterpart. Furthermore the colours of the candidate star are consistent with a main sequence star at a distance of 2-4 kpc. The probability of a chance coincidence with a normal star and the difficulty of explaining the lack of pulsed emission leads us to conclude that this object is an intermediate field star. 
A. Shearer, C. M. M. O' Sullivan, A. Golden, P. V. R. Garcia, M.   Redfern, A. Danks, M. Cullum