GBT Observations of Very Low Mass Binary Millisecond Pulsars: A Search   for Eclipses
  We searched for eclipses of two millisecond pulsars, PSR J1807-2459 and PSR B1908+00. These pulsars are in very low mass binary systems with orbital parameters similar to those of eclipsing binaries. Observations were made with the GBT at frequencies as low as 575 MHz. No eclipses were detected in either system. Observations of well-established eclipsing binary J2051-0827 found eclipses to be substantially weaker than previously seen, with the pulsar detected throughout the eclipse region at 575 MHz and with an electron column density an order of magnitude smaller than previously measured. 
David J. Nice (Princeton), Ingrid H. Stairs (UBC), Zaven Arzoumanian   (USRA, NASA-GSFC)