Abstract:
Ground layer turbulence is one of the important site characterization parameters used for
assessing the quality of an astronomical sites. Lunar Scintillometer (LuSci) is a simple, yet an
effective site-testing device for measuring the ground layer turbulence. The instrument consists
of a linear array of photodiodes which record the variations in moon's intensity caused by the
lower layers of the Earth's atmosphere. The covariance between all possible pairs of photodiodes
can be used to reconstruct the ground layer turbulence profile from the ground up to a maximum
height roughly determined by the distance between the furthest pair of detectors. The 6-channel
LuSci that we are developing at Indian Institute of Astrophysics is closely based on a similar
instrument recently built by the team led by Andrei Tokovinin of CTIO, Chile. We intend to use
this device with other site-testing instruments such as Multi Aperture Scintillation Sensor
(MASS) and Differential Image Motion Monitor (DIMM), which are at different stages of
development. In this work, we present the details of hardware design, signal acquisition and
inversion technique used to retrieve the relevant parameters of the atmosphere. Some preliminary
results from the on-site measurements and laboratory tests will also be described.
