teleskop-e patow-e iks (#), durbin-e ~ ~
Fr.: télescope de rayons X
A telescope designed to focus X-rays from astronomical objects. X-ray telescopes function from orbital satellites because X-rays are absorbed by the Earth's atmosphere. These telescopes require special techniques since the conventional methods used in optical and radio telescopes are not adequate. → grazing-incidence telescope; → Bragg angle.
teleskop-e sarsu, dvrbin-e ~
Fr.: télescope zénithal
A → telescope that is mounted on a → vertical axis or moves only a small amount from the vertical. It is primarily used to determine positional measurement of stars moving near the → zenith. The advantage is that there is no → atmospheric refraction occurring at the zenith. If a star on one night passes through the center of eyepiece, one must observe it six month later, and see if the star has been offset by the center. A shift would mean a measure of parallax. See also: → zenithal well.