Kwasan and Hida Observatories, Graduate School of Schience, Kyoto University japanese Home page

The 65cm Refractor Telescope

About the 65cm refractor telescope.

This telescope was constructed in April 1972, and is still the largest refractor telescope in the East Asia.

This telescope has two advantages that make it ideal for studying planets and/or the nuclei of comets: 1. its long focal lenght, and 2. the stable and clear observing conditions at Hida observatory. The telescope observes storms and clouds on Mars, and seasonal variations in its atmosphere.

In 2001, the 15m dome was repaired. This telescope is also used for the education of under graduate and graduate students.


One of the main objectives of this telescope is to investigate the variation of the Martian atmosphere and clouds. The following figures show Martian clouds taken with different filters. The use of different filters enables us to study the clouds in detail. (Top: with blue filters. Bottom: with red filters)

Nihon Shinku Kogaku Co. Ltd.
Instrument performance

The telescope

Apature650mm
Manufactured byCarl Zeiss Co. Ltd.
Focal length10,500mm
F/ratio16
Resolution0".18
Light gathering power8,600
Limitting visual magnitude16.2
Tracking accuracy0.1"/9'
Size of the housing930mm(diameter)x11,500mm
Total weight17 ton

The CCD system

CCD cameraSpectrasource Instruments Co. Ltd.HPC-1S
CCD chipKodak KAF1600-IUV
Chip size9 micro meter
Pixel number1522 x 1032
Bit depth16 bits
Controlling PCGateway 2000P5-133
Filters (For Mars)Nihon Shinku Kogaku Co. Ltd.
Blue filter436.2nm / 15.6nm
Yellow Filter588.3nm / 12.6nm
Red Filter647.2nm / 10.1nm
(Central wavelength / Band width)
Filters (For Jupiter)
Methane band890nm / 10nm
Continuum750nm / ----

Recent topics
HOPS
The "Hida Observatory Polarimetry System (HOPS)" is currently an on-going project to install a "Two-dimensional polarization imager" on the 65cm telescope. The present objective of this project is to investigate the polar hayes of Jupiter.

Recent work
Mars's polar cap.
Martian north polar cap 1996-1997.
K. Iwasaki, D. Parker, L. Larson, and T. Akabane.
Icarus 138, 20-24 (1999).
Clouds of Mars
Diurnal variation of Martian water-ice clouds in Tharsis region of the low latitude cloud belt: Observations in 1995-1999.
T. Akabane, T. Nakakushi, K. Iwasaki, S. M. Larson.
A & A 384, 678-688 (2002).
Mars's "blue clearing"
Mars: The cloud effect on the blue clearing in the Syrtis Major region.
T. Nakakushi, T. Akabane, K. Iwasaki, S. M. Larson.
J. Geophys. Res. 106, 5043-5056 (2001).