INSTRUMENTS

ASTRAL TELESCOPE

page 4

USE OF ALTAZIMUTH MOUNTING

MOVEMENT OF THE TELESCOPE
Typical azimuthal mounting (fig. 4) supplied with many telescopes for the amateur allow the observer to aim at celestial or terrestrial objects by means of a movement on two axes, horizontal or vertical. The movement can be done manually once the screws used for blocking movement have been loosened (sec the mounting section in the instructions manual).
During terrestrial observation, once the field of vision bas been framed in the finder, it will be necessary to block the instrument once again.
In the case of astronomic observation, where the stars seem to be in movement (in reality it is the earth that rotates on itself) it will be necessary to move the instrument delicately on both its axes. Some models have knobs or handles that allow for micrometric regulation.
This is different from those instruments with "equatorial' mounting. The movement cannot be motorized and this makes long exposure of the astronomic field impossible. This type of exposure is reserved for those instruments equipped with a small motor. In some cases it is possible to mount the optic of this instrument on an equatorial mounting but this is not advisable when the price is taken into consideration. Astronomy photography is limited to the Moon and the more visible planers.