RTT150
Russian-Turkish 1.5-m Telescope

International astrophysical space observatory INTEGRAL

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HEAD IKI

Observations planning

At first it is necessary to find out whether the selected object can be seen at the desired time. The main restriction: the height of object above horizon should be more than 30^o. Taking into account geographical location of observatory, declination of object should satisfy the d>-20^o condition.

The range of right ascensions which can be observed at a given time is defined as follows. At each moment of time those points of celestial sphere whose right ascension is equal to a local sidereal time (LST) are at the top culmination. The sidereal time at midnight (STM) is equal to ~12 hours in the end of March and increases by 2 h each month. In order to receive an approximate range of right ascensions of objects that will reach the top culmination during the night, it is necessary to add or take away from STM half of duration of night. By taking away we will receive right ascensions closer to the beginning of night, by adding - those closer to the end. For observations of weak objects (say, weaker than 19^m) it is also important that the Moon be in a minimum phase, i.e. night to be dark. The sidereal time at midnight, phase of the Moon, time of the beginning and the end of night can be found in the special almanac (or in its text version).

The periods of visibility for a given source in the nearest years taking into account Moon phases can also be calculated with the help of special calculator PROGNOZ (available in Russian).

If the object is available for observations at the desired time and has magnitude brighter than 20-21^m, it is necessary to write the application with a scientific substantiation of no more than 2 pages in volume and to send it to M.N.Pavlinsky. The application will be considered by scientific committee on distribution of observing time.

See also Turkish State Meteorological Service (cloudiness for Turkey and Europe).