The main instrument of the observatory is a 51-cm, f/13.5 Cassegrain reflector equipped with a single channel photoelectric photometer and a spectrograph. The photometer is used for accurate light measurement of the stars, which is the most popular work carried out in the observatory. The photometer is comprised of the following parts :

1. Phototube, { RCA C31034A or RCA 4509 } for converting the starlight to a weak electric current.

2. Amplifier

3. A/D converter and PC

4. Photometric filters : v , b , u , U , V, B , y , Ha W, Ha N, etc.

5. Thermoelectric cooler, for cooling of the phototube.

6. D.C. source, for supply of phototube high voltage up to 2000 volts.

7. Voltage stabilizer, for eliminating the variation in the urban electricity.

Photometric function is summarized below :
The star light is directed to the photomultiplier tube and is converted into a weak electric current in proportion to the intensity of the star light. The star light can be passed through special filters. The photocurrent, after being strengthen in the amplifier, which is connected to the telescope, is led to the A/D and PC.
The D.C. source supplies the high voltage needed by the photomultiplier tube. The digital recorder is used to record the photometric measurements in a digital format.
The telescope movement is controlled by a digital tracking system. The tracking instrument should be adjusted after being turned on. For the adjustment of this instrument, at first the sidereal time and the universal time should be supplied. Then, the telescope can be set on a certain star. The coordinates of the star (declination and right ascension) should be entered. So, by the ascertainment of the right ascension and declination celestial body the telescope can be directed to it. To use the spectrograph, the photometer must be detached and the spectrograph be mounted. This instrument is able to record the spectrum of the stars light on a 35mm film. Until now, this instrument has been used for training purposes only.