Near Infrared High Angular Resolution Observations of Stars and Circumstellar Regions by Lunar Occultations

The high angular resolution technique of lunar occultations enables one dimensional source structure in the direction of occultation to be extracted from the observed fringe pattern after detailed analysis taking into account the frequency response of the detection system, the optical filter bandwidth and the telescope size. A program of observing lunar occultations in the near infrared from 1.2m telescope at Gurushikhar, Mt Abu, India (72°47′E, 24°39′N, 1680m), is currently being pursued. Several occultations have been successfully observed in K band (2.2μm) including a day time event. The instrument used was a InSb based infrared high speed photometer, the details of which are given in a earlier paper (Ashok N.M., Chandrasekhar T. and Sam Ragland, 1994, Experimental Astronomy, 4, 177).