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7.3. Telescope and atmospheric conditions
Telescope has a high magnification. In this case one should remember the
following feature. When increasing a magnification of telescope a distortion of
image to be made by aerial heterogeneity becomes more visible. It is a scintillation
and distortion of image of remoted objects, scintillation and distortion of image
of stars, reduction of sharpness of small parts of Moon and stars. So, one should
make a testing of telescope resolution by double pares of equal brightness and
permeability by photometric standards, observation of little contrast parts of
planets in good atmospherical conditions such as calm, high transparence of
atmosphere and low turbulent air torrents.
Because a resolution of telescope TAл-200K is sufficiently high the testing
should be made in atmospherical conditions which are valued by Pikering’s
scale. It is 6 scopes that to allow obtaining the satisfactory and good images
when diffractional disk of star is visible constantly.
There are some meteorological factors, which can reduce a quality of image
such as mist, dust and so on. These factors reduce a transparence of atmosphere
that to reduce a permeability of telescope considerably. This factor is especially
noticeable in observation of remoted objects, but sharpness of image is not
changed.
It is not necessary to remind that observation through the window is possible if
the ambient temperature in the room and temperature out of door are not different.
Otherwise the warm air coming out of the window deteriorates the images so
that observations are impossible whatsoever. Besides, inequality of surfaces of
window can distort an image.
If it is necessary to make an observation out of door, one should stay the
telescope in the street within 30 minutes so that all parts of telescope have the
same temperature.
In observation at cold damp nights a moisture can penetrate into the telescope
tube. If the telescope is covered, optical surfaces can get misted under direct
sunlight. So, one should protect the telescope from the direct sunlight. It is
recommended to stay it in dark cold room for some time. But if the mirror got
misted it is not necessary to wipe it. One should open the telescope and stay it
within 30 minutes in daylight. The moisture is evaporated in full.
After operation one should pack the telescope and store it according to the
rules of storage.
