This entry is missing Overview , add relevant content to make the entry more complete, and it can also be upgraded quickly. Hurry up edit Come on! The two speed lunar camera is an instrument attached to the astronomical telescope, which is used to take pictures of the moon and stars on the same photographic film at the same time for precise positioning of the moon. It is designed by American Malkowitz, also known as Malkowitz camera.
- Chinese name
- Two speed lunar camera
- Foreign name
- dual-rate lunar position camera
- Alias
- Malkowitz camera
- designer
- Malkowitz
From the fifties to the sixties of the twentieth century, it was used to determine the geocentric coordinates of the almanac or station. In order to track and shoot the moon image and the star image at the same time, the instrument is required to compensate the motion of the moon relative to the star and weaken the strong light of the moon. For this reason, a piece slightly larger than the diameter of the moon image is placed in front of the negative Neutral filter 。 Before observation, according to the speed and direction of the moon movement calculated in advance, make the filter wrap around the axis in a specific direction. During about 20 seconds of exposure time, the moon will not move relative to the star. When the filter is parallel to the negative, record the observation time. The periphery of the filter is a piece of flat transparent glass with the same thickness and refractive index as the filter, which is used to ensure that the moon and stars are imaged on the same focal plane. In order to meet the requirement of tracking stars with accuracy of 01, two motors are used. One is used to drive the negative box to track the stars; the other is used to rotate the filter to compensate for the motion of the moon relative to the stars. Hence the name of the two speed lunar camera. Due to the improvement of the tracking accuracy of the telescope, the motor driving the negative box was later omitted 
