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

The 60cm Reflector Telescope

About the 60cm reflector telescope

The 60cm reflector telescope was constructed in 1965. This telescope was initially located at Kwasan observatory, but was transfered to Hida observatory in 1968, shortly after its opening. Since its construction, this telescope has been used for observations which require a wide field of view, such as studies of comet's tails. More recently, in order to study stellar atmospheres (especially of variable stars), we have been improving the telescope's imaging devices and spectrometers.

The performance.

The telescope

Manufactured byTsugami Co. Ltd.
Focal length3300 mm (Newton focus: Main focus)
12000 mm (Cassegrain focus)
F/ratio5.5 (Newton focus)
20.0 (Cassegrain focus)
Light gathering power7,400
Limitting visual magnitude16.1
Tracking accuracy1.5"/30'
Size of the housing860mm(diameter)x3,700mm
Total weight4.5 ton
Imaging Devices

With and without the B/V/R/I filters by Johnson/Cousins(Bessel), we usually perform intensity measurements of stars by cooling the CCD camera with liquid nigtrogen. We are also developing a new spectrometer.

Recent topics
Intensity-variation of cataclysmic variable stars

The left figure demonstrates an ultra intense brightening (up to 100 times the usual intensity) of the cataclysmic variable star "MN Dra" in Dragon over a period of two weeks. A "cataclysmic star" is a kind of "variable star", but changes its intensity more rapidly than most variable stars.

The x-axis is the Julian Date, and the Y-axis is the relative magnitude*1 against the reference star.

Such significant brightenings are considered to be caused by rapid heating of the accretion disk*2. From this figure, one can see a 25 % intensity-variation in a period of just 2.5 hours, and thus infer that the accretion disk is distorted by the tidal forces caused by the disk and companion's rotation.

  1. The intensity of a variable star is obtained by measuring the relative difference in intensity between the star and the nearby non-variable star (reference star).
  2. A gasous object rotating in the form of a disk around a very heavy object (c.f.: right figure).

Recent results.
Photometric Observations of an SU UMa-type Dwarf Nova, VW Coronae Borealis, during Outbursts
D. Nogami, M. Uemura, R. Ishioka, T. Kato, J. Pietz, 2004,
2004, PASJ, 56, S155
In-the-gap SU UMa-type dwarf nova, Var73 Dra with a supercycle of about 60 days
D. Nogami, et al.,
2003, A&A, 404, 1067
Structure in the early afterglow light curve of the gamma-ray burst of 29 March 2003
M. Uemura, et al.
2003, Nature, 423, 843