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

The Domeless Solar Telescope (DST)

About the DST

The Sun is the only star for which we can observe fine details on its surface and investigate the associated activity. Once the underlying physics has been established, it can be applied to the understanding of other activities in the Universe.

The Domeless Solar Telescope (DST) was designed to acquire solar surface images at the highest spatial resolution. Since its establishment in 1979, the DST has contributed to the great scientific progress in recent years in the understanding of the mechanisms which cause solar explosive events, and other phenomena in space plasma physics.


Horizontal sppectrograph

There are two types of spectrographs attached to the DST: A vacuum vertical spectrograph which has the highest wavelength resolution in the world, and a horizontal spectrograph that can image the entire visible solar spectrum. These two spectrographs are used to study the physical properties of small-scale solar atmospheric structures and explosive events.
[Details about the vertical spectrograph (Japanese)]
[ Details about the horizontal spectrograph (Japanese)]

The DST Lyot filter has a very narrow passband of 0.25 angstroms, and provides arbitrary wavelength tuning. With this filter, we can see the three-dimensional velocity structure of the solar atomosphere.

Observational room

Example observations.
Eruptive prominence
An image using the vertical spectrograph
Two ribbon flare
Example from the horizontal spectrogarph
Example of the spectroheliogram

You can find more information, images and movies obtained by the DST via the link below.
DST images and movies (Japanese)

Operating the DST

The file sizes are somewhat large, so it may take some time to download them.

  1. Automatic guide to make the telescope point toward the Sun. [QuickTime (4.5MB)], [GIF animation (4.9MB)]
  2. To open the entrance lid and let in the Sun's light. [QuickTime (7.2 MB)], [GIF animation (7.4MB)]
  3. At the start of daily operations, the observer searches for an object suitable for the scientific purpose of his research, such as a prominence, some emerging flux, spots, etc. When the object comes into the field of view, the observer can look at its 3D structure by changing the observed wavelength. [QuickTime(14 MB)], [GIF Animation(32 MB)]

Obsevational Report
The observational report of the DST

The performance
TypeDomeless Tower Vacuum Telescope
Optical typeGregorian type reflector telescope
Effective apature600 mm
Focal length of objective mirror3,150mm
Total focal length32.19m
Total F ratioF/53.7
Resolution0.18 arcsec at 500 nm
The diameter of the solar image299.95 mm = 1922 arcsec
(1arcsec = 0.1561 mm)
Tracking systemPhotoelectric sensor
Pressure inside the vacuum chamber2 - 5 mmHg
Mount typeAltazimuth mount
Total weight21 ton
The structure of the DST

Optics TypeCzerny-Turner typeVacuumed Czerny-Turner type
Focal length10m14m
Dispersion0.33 A/mm (2nd order)0.14 A/mm (5th order)
Effective wavelength range3600 - 15000 A3600 - 15000 A
Total weight3 ton10 ton
NoteSimultaneous observation
of all the visible spectrum can be done.
High dispersion and high resolution