Estimate on SOT light level in flight with throughput measurements
in SOT sun test
T. Shimizu, T. Tarbell, Y. Suematsu, M. Kubo, K. Ichimoto,
Y. Katsukawa, M. Miyashita, M. Noguchi, M. Nakagiri,
S. Tsuneta, D. Elmore, B. Lites and SOT team
Solar-B SOT (solar optical telescope) consists of optical telescope
(OTA) and focal plane instruments (FPP). The solar light into the
telescope penetrates through many numbers of optical elements
located in OTA and FPP before illuminating CCDs. Natural sun light
was fed to the integrated SOT in two sun-test opportunities.
CCD exposures provide the number of photons accumulated in an
exposure duration in clean room test condition. To estimate one
solar light level in flight (without earth atmosphere attenuation),
a pinhole-PSD (position sensitive detector) sensor (525 nm band)
was used to monitor the light level simultaneously. This sensor
was pre-calibrated with continuous monitoring the solar light level
in a day long under a clear constant sky condition, giving
what is the voltage for one solar light level. Transmissivity of
heliostat two flat mirrors plus clean-room entrance window glass
was also measured as a function of wavelength. This throughput
measurement with solar light has confirmed expected number of
photons and suitable exposure durations in flight.
Correspondence
Toshifumi Shimizu (shimizu@solar.isas.jaxa.jp), ISAS/JAXA
presentation
poster