Description of design

Axial Meridian Circle (AMC) is a modern robotic telescope having unique design features ( G. Pinigin, O. Shulga. Patent 35905A, on 16.04.2001 ), which correspond to the best ones of meridian telescopes in the world and some parameters, such as weight and thermal deformations, even exceed them. AMC was put into operation in 1995. Because of the unique design features, AMC was inscribed in a list of scientific objects that represents the National Heritage of Ukraine by the Decree #1709 issued by the Government of Ukraine on December 19, 2001.

amc2
Pic.1
1- telescope, 2- western plain bearing, 3- CCD camera,
4- western bed, 5- long-focal length autocollimator.

AMC design consists of a horizontal rotating telescope in the prime vertical and a motionless long-focal length autocollimator (Pic.1). CCD camera is installed in the telescope focal plane to measure the exact moment of the star passage through the meridian plane. An optical-mechanical system (OMS) of the AMC is installed on two beds inside an enclosure. A telescope, a central optical unit, reading microscopes and an objective of autocollimator are installed on western bed.

amc3
Pic.2
1- objective of telescope, 2- reflecting prism,
3- glass limb, 4- eastern plain bearing.

The central optical unit, which consists of reflecting prism and glass limb, is attached to the telescope tube (Pic.2). The reflecting prism has two flat mirrors with 45° between them. Diagonal flat mirror reflects luminous flux from celestial bodies into the objective of telescope. Another flat mirror is installed perpendicularly to the rotation axis with accuracy of ±20", providing a reflection of luminous flux from artificial marks back into the objective of autocollimator. A part of this luminous flux passes into the telescope through a small hole in the center of the reflecting prism. Positions of the marks are measured in the telescope focal plane. It allows us to determine accurate positions of celestial bodies taking into consideration instrumental parameters.

amc4
Pic.3
1- focal OMS of the autocollimator, 2- CCD camera,
3- autocollimator tube, 4- eastern bed.

Systematic instrumental errors are from ±0."02 to ±0."03
A roof of enclosure above the central optical unit has a sliding slit, which allows us to carry out observations in the meridian plane.
A focal OMS of the autocollimator, which provides a formation of direct and reflected marks as well as measurements of their coordinates, is installed in the focal plane (Pic.3). This OMS is installed on the eastern bed. An autocollimator tube, laying between two beds, provides a passage of light with minimal influence of air turbulence on the image quality of marks. Coordinates of marks are measured with CCD camera working in TV mode.

amc4
Pic.4
1- control system, 2- control computer.

There are two rooms for the control system, which allows us to carry out observations in manual or automatic mode (Pic.4). Integrated software provides a preparation of input data for observations, raw data processing, determination of object coordinates, statistical calculations, storage of data.