The coronagraph-1 (KG-1) was designed by the State Optical and Mechanical Plant according
to the Lyot layout and put into operation in 1951. Positioned on the equatorial mounting,
it is a refractor with the 21-cm objective. The objective is made of glass K8. It is a
convex-plane lens 10 mm thick with the 350-cm focal length in the H-alpha 6562.8 Å line.
The telescope is used for chromospheric monochromatic observations of prominences,
filaments, active regions and flares in the H-alpha line. In the focal plane of the
objective there is a diaphragm cutting out a part of the solar image. Next to the
diaphragm there is another objective. Passing through it, a beam becomes parallel. Then
light falls on the diagonal mirror and interference-polarization filter (IPF). After IPF
light goes to the diagonal mirror, then to the lens of the field, and depending on the
rotary motion of the third diagonal mirror, either to the ocular or to the digital camera.
The focal length of this layout is 7 meters. The 12-cm image of the Sun is built up in the
focal plane. Optical resolution of the telescope is 1.5.
1 Interference-polarization filter Halle. The passband is 0.5 - 1 Å, a shift to wings up
to 1 Å is allowed. The temperature of IPF is controlled by a thermostat; working
temperature is 40.7 ?.
2 Digital camera Canon EOS 1000D, reflex camera with a portable objective, 10.50 million
pixels, matrix: 22.2 x 14.8 mm.
An image of a part of the solar disk (3888 õ 2592 pixels or 355.5 õ 266.6 angular
seconds in size) is taken with the digital camera. The image is oriented across the
diurnal circle. Observations are carried out in the center and in wings of the H-alpha
active regions and filaments on the solar disk, as well as prominences on the limb.
The archive of images in the H-alpha line is here.
Send notes and request to Shakhovskaya A.N. firstname.lastname@example.org