Frame mounting
The astronomers describe a frame mount as a parallactic or equatorial mount that was developed especially for heavy astronomical telescopes . Since it was derived from the English mount , it is also known as the English frame mount.
As with the other types of equatorial mounting, the “ hour axis ” points to the respective celestial pole, but it is not supported on a column, but on two solid foundations . This means that the axis around which the telescope system moves on a daily basis can also accommodate heavy loads of several dozen tons.
The first large-scale implementation of this type of mounting took place with the construction of the 100-inch reflector of the Mount Wilson Observatory . At Mount Palomar - Observatory of the frame towards the North Pole has been opened horseshoe-shaped, to facilitate access to the near-pole area. For mechanical reasons, frame mounting is better suited for a low geographical latitude than for high latitudes , which in any case corresponds to the prevalence of large observatories .
Some three- and four-axis satellite cameras have a special form of frame mounting in order to be able to measure even weak or distant earth satellites . With the Baker-Nunn camera , the measuring chamber is mounted in its own frame, which is aligned transversely to the plane of the satellite orbit and rotated after the satellite so that it is shown as a short track , while the star background has longer tracks.