Up to now we have identified only five gamma-ray sources of TeV energy region.
These sources ware detected by Cherenkov imaging telescopes.
The Cherenkov technique which can distinguish between the gamma-rays
and cosmic rays by using difference of air shower images is
going to succeed as high energy gamma-ray astronomy
owing to improvent of equipment and imaging analysis method.
The Telescope Array project which utilize the above experimental
techniques is going to observe celestial objects by many
compact reflectors and get three dimensional shower images.
This array has a good ability to distinguish between primary
gamma-rays and protons, and determine energy or arrival
direction of primary cosmic rays with more accuracy than ever.
we expect that origin and acceleration mechanism of cosmic
rays are demonstarate by measurement of spectrum of
pulsar and supernova remnants in our galaxy and AGNs of extra galaxy.
As the first step of this project, we installed two 3m diameter imaging
Cherenkov telescopes at Akeno observatory in Yamanashi pref.
in 1995 and observed one of the TeV gamma-ray source candidate,
Mkn421, from February to May 1996 and analysed the obtained data.
Also we studied the performance of prototype telescope, observation
method and imaging analysis method.