GENERAL DESCRIPTION OF THE EQUIPMENT 
Purpose of the Equipment 
The Automated High Accuracy Coordinate Measuring Equipment (AHACME) 
provide a means of measuring distance between star images or other data 
points on a photographic plate. It will accept, as input data, photographic 
plates up to 308 mm. x 308 mm. in size, along with certain data constants 
regarding the images which are entered on a ten-decade keyboard, Itwill 
determine the coordinates of any desired number of images within an area 
of 200 mm. x 200 mm. on the photographic plate to an accuracy of +0. 5 
micron (0.0005 mm. ) cumulative error, with a least count equal to 0.25 
micron. 
The device will provide intermediate output data consisting of: 1) a paper 
print-out of the rough metric coordinates of all desired images, as deter- 
mined by a manual scanning operation, with their related constants; and 
2) a file of IBM cards containing the same data, It will be possible to set 
the coordinate system zero reference to correspond to any image point, or 
to a fiducial marker. The final output data will consist of a paper print- 
out of the high accuracy metric coordinates of the same images, with their 
related constants, and a file of IBM cards containing the same data. These 
coordinates will normally be determined by fully automatic means, with 
provision for manual override when desired. It will be possible to set the 
high accuracy coordinate system zero reference to coincide with any point 
or fiducial marker. The zero reference chosen for the high accuracy read- 
out can be independent of the zero reference for the rough coordinate sys- 
tem. 
If it is desired to repeat the high accuracy measurements using a trans- 
lated coordinate system, so that the zero reference lies on a different 
image, it will be possible to do this as many times as desired without re- 
peating the manual determination of the rough coordinates on the preview- 
er. 
Configuration 
During operation, the environment will be maintained within the tempera- 
ture limits of 74-78°F and 40-50% relative humidity. To minimize heat 
transfer to the thermally critical equipment, all electronic circuitry which 
does not require manipulation by the operator during normal use is located 
behind a transparent screen which divides the equipment rocm. All vibra- 
tion producing equipment is isolated on shock mounts, and the measuring 
machines themselves are similarly isolated. 
In the operating area, there are two measuring tables, whose design and 
construction are compatible with the very stringent accuracy requirements 
for the comparator output. There is an operator's position at each of the 
measuring tables.