Determination of the Hubble Space Telescope effective conic-constant error from direct image measurements.

Direct measurement of discernible features in the Hubble Space Telescope (HST) imagery has enabled a self-consistent determination to be made of the effective conic constant of HST images taken with planetary camera 6 (PC-6) of the wide field and planetary camera. Before being corrected for the contribution from PC-6, the conic constant is - 1.01429 +/- 0.0002. The correction for PC-6 is less accurately determined but probably lies between -0.0002 and 0.0004. As a result the HST optics are characterized best by a conic constant of - 1.0140 +/- 0.0003 as obtained from direct image measurements.

A hartmann test reduction program.

A generalized Fortran program for the reduction of Hartmann test data has been written. A brief review of the mathematical echnique is given, along with a discussion of the measuring methods and the results of some tests of the accuracy of the program.

Anastigmatic cassegrain type telescope.

The 152-cm telescope of the Cerro Tololo Inter-American Observatory in Chile is to be made to a design producing images that are free of the usual Ritchey-Chrétien astigmatism. A 38-cm diam fused-quartz correcting plate is used to give a field diameter of 1. degrees 5, over which images are less than 0.5 see of arc in diameter.

Prime focus correctors involving aspherics.

The 380-cm Kitt Peak telescope will have an f/2.8 hyperbolic primary. Three tentative field correctors for prime focus use are described; they each have one or more aspheric surfaces.

Flat-field spectrograph camera designs.

The final designs for the short-focus spectrographic cameras for the 213-cm Kitt Peak reflector are here defined. Duplicates of some of these cameras will be used also on the 152-cm telescope of the Cerro Tololo Inter-American Observatory in Chile.