STEREO VISION - Cont. Eye base (interpupillary distance) - In designing binocular instruments the interpupillary distance adjustment range is usually from 50 to 76 mm. d = eye base for the "standard observer". d = 62mm or 2.5 in., approx.

Analytic methods are available for evaluating aerial camera resolution in the presence of aberration and random wavefront degradation. These methods are illustrated by considering imagery on Pan-X type emulsion for a defocused f/3.5 lens viewing through an aircraft camera window.

In order to measure the daytime sky radiation characteristics from 20,000 ft. to 200,000 ft., a spectrophotometer was developed to be operated in two high altitude vehicles. This paper describes the spectrophotometer, the technique of calibration, and reviews the results of the sky measurements from the first Research Vehicle. Data measured included hemispherical sky spectral radiance, luminance, polarization, albedo, and integrated near-infrared from 20,000 ft. to 70,000 ft. Measurements of spectral radiance included from 0.36 through 0.75 microns with a bandwidth of better than 15 nanometers. Data from the second Research Vehicle, the X-15, obtained from 53,000 to 190,000 ft. is presented. Correlation is made with the measurements from the first Research Vehicle as well as with corresponding data available in the literature and with corresponding theoretical sky characteristics.

The increasing interrelationship between different areas of research is making essential the establishment of better interdisciplinary communication. The photo-optical instrumentation engineer, who formerly was concerned only with such matters as resolution and other physical optical problems in designing lens systems that transmit light for viewing by the human eye, must now consider the biological effects of light energy on the retinal hypothalamic endocrine system and its ultimate influence on hormone production and environmental health factors.

A fine guidance experiment is discussed which is concerned with the improvement of pointing stability in space to accuracy in the order of .01 arc second. This need has become apparent to realize the potential of large (120") diffraction limited telescopes in space. Stability in this order over many hours is required to permit long time integration of the energy from dim and distant stars. The telescope upon which the experiment is based has a completely self-contained attitude control system, and in floated or non-mechanical suspension the telescope will practically constitute an independent space vehicle within its range of motion.

In recent years photosensitive electrical devices have become increasingly diversified and of growing importance in our space-age technology. None of the devices are uniformly sensitive to all colors and the response of many extends beyond the visible portion of the spectrum; their characteristics must he known in order to select the right type for any application.