High-Resolution Photography of the Moon with Very Short Exposure Times.

Abstract

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS High-Resolution Photography of the Moon with Very Short Exposure Times. Martz, E. P., Jr. Abstract Very short exposure time photographs of the moon have been secured with to 000 ASA film and long focal length, large- aperture telescopes in an effort to negate the image blurring effects of astronomical "seeing." With the 60-inch aperture, 300-ft focal length McMath solar telescope at Kitt Peak Observatory exposure times of the order of 0.0t sec were employed near the terminator at first quarter moon. Surface resolutions comparable to the best photographs secured to date with conventional techniques on the tOO-inch reflector were secured on three nights with ver~ poor seeing conditions at Kitt Peak. The improvement with 0.0t sec exposure over photographs taken with 0.02 sec exposure was very marked due to the "freezing" of the seeing image. With a 16-inch Cassegrainian reflecting telescope operating at Table Mountain Observatory under somewhaL better seeing conditions, at t50-ft equivalent focal length, lunar surface resolutions near the theoretical limit of the telescope were secured with 0.03-sec exposure time on to 000 ASA film whereas 0.t3-sec exposures on slower 3000 ASA film were definitely inferior. The to 000 ASA film 0.03-sec exposures show markedly better resolution than 0.5-sec exposures on conventional 50-too ASA panchromatic film. It was found possible to increase the speed of the 10 000 ASA film by a factor of 2 by heating the camera back to t 15 0F during exposure and development. It was further found that pre-exposure fogging of the film by skylight, during daytime telescopic photography of the moon, increases the 10 000 ASA film speed by a factor of 10. This technique is being refined for application to night time lunar photography which should make possible exposure times near the lunar terminator at half moon of the order of 0.001 sec at f/60. It is believed that with a 60-inch aperture and 300-ft focal length the theoretical resolution of 0.077 sec of arc should be achieved, yielding lunar surface detail resolution of the order of 500 ft. Publication: The Astronomical Journal Pub Date: 1963 DOI: 10.1086/109122 Bibcode: 1963AJ.....68R.540M full text sources ADS |