Near-Infrared Solar Electric Field Telescope

The infrared monochromatic image of corona was reported in 1975.The Solar Inf rared electric field observing and researching was proposed in 1986 and infrared solar magnetic field observing was suggested in 1987.These observing data describes various states of solar atmosphere.To varying degrees, compared with traditional system, near infrared system has its special characteristics. In this paper, we present a vacuum solar telescope with a near-infrared (at 8438 angstrom ～10830 ang strom)filter system which is desig ned to measure the solar electric field in Huairou workstatio n of Beijing Ast ronomical Observatory (BAO).The vacuum optical telescope will consist of a primary mirror in 35cm Diameter, a Gregorian mirror, two vacuum windows, a collimating lens and an imagine lens.The filter with polarizing analyzer will consist of two prefilters, one liquid crystal analyzers, a universal biref ringent filter which spectral range is in 8000 angstrom ～11000 angst rom and pass-band 0.25 ang strom at 10830 ang strom.The biref ringent filter and the optical system of the telescope are described in details.We expect to achieve an electric field observing system, two-dimensional monochromatic image observational system of corona.It also can be turned across the spectral line to obtain line prof iles of two-dimensional of the field.