20
indicator blinks. If the button 3 is released the tracking speed returns to the
nominal.
The telescope has high magnifications and, hence, small fields of view,
therefore it is provided with a finderscope.
After mounting the telescope it is necessary to set parallel of the optical axes
of the telescope tube and finderscope. For this purpose one should mount a
reticle with cross into the eyepiece f'=25 mm. One should make an adjustment
by remoted object.
By operating with the set screws of rings of the finderscope one brings the
chosen remote object to the center of the finderscope field of view. This operation
is performed once. In the future before observation only a check-up of parallelism
of the telescope and finderscope optical axes is needed.
In order to avoid corrections of the declination axis during operation of the
watch mechanism it is required to set the telescope polar axis in parallel to the
celestial axis. In this case the northern (upper) end of the polar axis faces the
celestial pole positioned near Polaris (
α
Ursae Minoris). For visual observations
it is enough to incline the polar axis at an angle equal to the latitude of the
observing site and direct it approximately along the line the South - the North.
With such coarse setting of the telescope the object will “deviate” step by step
in declination (it is lifted or lowered in the field of view). This error is corrected
at times by means of the micrometer screw of the declination axis.
For photographic operations and in the case when the telescope can be set
stationary, the polar axis of the telescope should be set precisely. For this purpose
one observes any bright star in the East, then in the South and makes notice of
the direction of the star displacement.
If in observation of the star in the East it is displaced in the telescope field of
view so that in its tracking the upper end of the telescope tubes sinks slowly, the
north end of the polar axis should be somewhat lifted.
If the upper end of the tube is lifted step by step, the north (upper) end of the
polar axis should be lowered.
For precise setting of the axes by azimuth one observes the star near the
meridian circle (above the south point) in the same way. If in the star tracking
one has to lower slowly the upper end of the telescope tube, the north end of the
polar axis should be displaced to the West. If in the process of the star tracking
the upper end of the telescope tube is lifted, the north end of the polar axis should
be displaced to the East.
In 20-30 minutes of such observations one can set the polar axis so that
the star will remain on the cross hairs for 0-5 minutes without correction in
declination.
After precise setting of the polar axis one can set the declination and hour
circles which must help to search the objects invisible with a naked eye or even
through the finderscope.
First of all one should set the hour circle which is fixed on the polar axis. After a
fine setting of the polar axis set the declination axis horizontally. The horizontal setting
should be checked with the aid of a level. After setting of the axis one sets the hour
circle so that “0” is found against the index. Fix tile circle by means of screws.
