Contrast and signal-to-noise ratio in long-distance starlight imaging

Journal Article · Mon Jul 01 04:00:00 EDT 1996 · Applied Optics

DOI:https://doi.org/10.1364/AO.35.004173· OSTI ID:383718

Priedhorsky, W C ^[1]

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1. Los Alamos National Laboratory, Mail Stop D436, Los Alamos, New Mexico 87545 (United States)

A small telescope on an airplane or in low Earth orbit can, in principle, resolve ground objects under starlight with useful resolution. For an {approximately}50-cm aperture and {approximately}100-s exposure, one can obtain a resolution of tens of centimeters from an aircraft and a few meters from orbit. Such starlight images are photon poor, and feature detection depends on photon statistics. Scattered light, atmospheric absorption, and foreground airglow all degrade image contrast. I report an investigation into image signal-to-noise ratio using first-order analytical approximations. We find that, for a given angular resolution, the signal-to-noise ratio for spaceborne images is degraded approximately a factor of 1.7, compared with airborne images, by foreground airglow. Image signal-to-noise ratio improves as the passband moves to the red and as skies become brighter from artificial illumination. {copyright} {ital 1996 Optical Society of America.}

• Sponsoring Organization: USDOE
• OSTI ID: 383718
• Journal Information: Applied Optics, Journal Name: Applied Optics Journal Issue: 21 Vol. 35; ISSN APOPAI; ISSN 0003-6935
• Country of Publication: United States
• Language: English

Related Subjects

44 INSTRUMENTATION
INCLUDING NUCLEAR AND PARTICLE DETECTORS
DESIGN
IMAGE PROCESSING
NIGHT SKY
PERFORMANCE
PHOTODETECTORS
TELESCOPES