Abstract
The apparent brightness of the moon depends on viewing geometry, which is defined by the incident angle, the emission angle and the phase angle of the sunlight. A photometric correction function to estimate the exact reflectance of the moon is necessary for each wavelength. However the lunar surface photometric correction function for the two bands (1250 nm and 1550 nm) of Multi-band Imager onboard SELENE (KAGUYA) has not been optimized. A near-infrared (NIR) telescope has been developed to obtain the NIR moon image at various phase angles and to estimate the photometric functions of the moon for these bands. We observed the moon with a CMOS camera (XEVA-FPA320, XenICs) mounted on a telescope through the bandpass filters of 1250 nm and 1550 nm central wavelength (125FS10-25 and 155FS10-25, Andover Co.). The telescope is a refracting-type telescope (ED102SWT, Vixen) and its aperture size is 102 mm and its focal length is 920 mm. Tracking with a motor-drive equatorial mounting, we observed some fixed stars, Vega, and the moon. This time, we discuss the method of estimating lunar surface photometric functions at 1250 nm and 1550 nm and preliminary ones within the obtained data to date.
