Journal of the Association of Lunar & Planetary Observers
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
A DESCRIPTION of FOUR FAST SLITLESS SPECTROGRAPHS by Gale A
A DESCRIPTION OF FOUR FAST SLITLESS SPECTROGRAPHS by Gale A. Hawey kngley Research Ceater Langley IStation, Hampton, Va. I .I NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTO 0CT.OBER 1967 , 8l .~ -. .y-; $. .Ir* *. r., \. ',r <'. /. ., ..., I 5,, 2 .,i c, . B TECH LIBRARY KAFB, NM . -- 0130742 NASA TN D-4145 A DESCRIPTION OF FOUR FAST SLITLESS SPECTROGRAPHS By Gale A. Harvey Langley Research Center Langley Station, Hampton, Va. NATIONAL AERONAUTICS AND SPACE ADMINISTRATION For sale by the Clearinghouse for Federal Scientific and Technical Information Springfield, Virginia 22151 - CFSTl price $3.00 A DESCRIPTION OF FOUR FAST SLITLESS SPECTROGRAPHS By Gale A. Harvey Langley Research Center SUMMARY A description, comparison, and short discussion of four fast slitless spectrographs for use in low-light-level research are given. The spectrographs include three catadiop- tric systems, the Super Schmidt meteor camera, the Baby Schmidt, and the Maksutov and one refractive optical system, the Super Farron. The Baby Schmidt and the Maksutov systems have fused-silica transmission elements. Except for the Super Schmidt camera, which utilizes a light flint mosaic prism, all systems utilize objective transmission dif- fraction gratings. The four systems discussed have low-light-level spectroscopic recording capability, The Super Schmidt has the largest field, 57'; the Baby Schmidt and Maksutovs have the broadest effective spectral range (3200 angstroms to 9500 angstroms); and the Super Farron features the greatest versatility and portability. INTRODUCTION A spectrograph is an apparatus which effects dispersion of radiation for photo- graphic recording. A slitless spectrograph consists basically of a dispersion element, prism, or grating, placed over the entrance of a camera so that images or the radiation source rather than the entrance slit of the more customary slit spectrograph are formed. -
A Theory of Catadioptric Image Formation * Simon Baker and Shree K
A Theory of Catadioptric Image Formation * Simon Baker and Shree K. Nayar Department of Computer Science Columbia University New York, NY 10027 Abstract able is that it permits the generation of geometrically Conventional video cameras have limited fields of correct perspective images from the image(s) captured view which make them restrictive for certain applica- by the catadioptric cameras. These perspective images tions in computational vision. A catadioptric sensor can subsequently be processed using the vast array of uses a combination of lenses and mirrors placed in techniques developed in the field of computational vi- a carefully arranged configuration to capture a much sion which assume perspective projection. Moreover, if wider field of view. When designing a catadioptric sen- the image is to be presented to a human, as in [Peri sor, the shape of the mirror.(s) should ideally be selected and Nayar, 19971, it needs to be a perspective image in to ensure that the complete catadioptric system has a order to not appear distorted. single effective viewpoint. In this paper, we derive the In this paper, we begin in Section 2 by deriving the complete class of single-lens single-mirror catadioptric entire class of catadioptric systems with a single effec- sensors which have a single viewpoint and an expres- tive viewpoint and which are constructed just using a sion for the spatial resolution of a catadioptric sensor single conventional lens and a single mirror. As we will in terms of the resolution of the camera used to con- show, the 2-parameter family of mirrors which can be struct it. -
ALD13 Advanced Lens Design 13
Advanced Lens Design Lecture 13: Mirror systems 2013-01-21 Herbert Gross Winter term 2013 www.iap.uni-jena.de 2 Preliminary Schedule Paraxial optics, ideal lenses, optical systems, raytrace, 1 15.10. Introduction Zemax handling Basic principles, paraxial layout, thin lenses, transition to 2 22.10. Optimization I thick lenses, scaling, Delano diagram, bending 3 29.10. Optimization II merit function requirements, effectiveness of variables 4 05.11. Optimization III complex formulations, solves, hard and soft constraints zero operands, lens splitting, aspherization, cementing, lens 5 12.11. Structural modifications addition, lens removal Geometrical aberrations, wave aberrations, PSF, OTF, sine 6 19.11. Aberrations and performance condition, aplanatism, isoplanatism spherical correction with aspheres, Forbes approach, 7 26.11. Aspheres and freeforms distortion correction, freeform surfaces, optimal location of aspheres, several aspheres 8 03.12. Field flattening thick meniscus, plus-minus pairs, field lenses Achromatization, apochromatic correction, dialyt, Schupman 9 10.12. Chromatical correction principle, axial versus transversal, glass selection rules, burried surfaces 10 17.12. Special topics symmetry, sensitivity, anamorphotic lenses high NA systems, broken achromates, Merte surfaces, AC 11 07.01. Higher order aberrations meniscus lenses Advanced optimization local optimization, control of iteration, global approaches, 12 14.01. strategies growing requirements, AC-approach of Shafer 13 21.01. Mirror systems special aspects, bending of ray paths, catadioptric systems color correction, straylight suppression, third order 14 28.01. Diffractive elements aberrations 15 04.02. Tolerancing and adjustment tolerances, procedure, adjustment, compensators 3 Contents 1. General properties 2. Image orientation 3. Telescope systems 4. Further Examples 4 General Properties of Mirror Systems . -
Magnetic Signature of the Lunar South Pole-Aitken Basin: Character, Origin, and Age Michael E
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. ???, XXXX, DOI:10.1029/, Magnetic signature of the lunar South Pole-Aitken Basin: Character, origin, and age Michael E. Purucker,1 and James W. Head III,2 and Lionel Wilson3 Abstract. A new magnetic map of the Moon, based on Lunar Prospector (LP) mag- netometer observations, sheds light on the origin of the South Pole-Aitken Basin (SPA), the largest and oldest of the recognized lunar basins. A set of WNW-trending linear to arcuate magnetic features, evident in both the radial and scalar observations, covers much of a 1000 km wide region centered on the NW portion of SPA. The source bodies are not at the surface because the magnetic features show no first-order correspondence to any surface topographic or structural feature. Patchy mare basalts of possible late Imbrian- age are emplaced within SPA and are inferred to have been emplaced through dikes, di- rectly from mantle sources. We infer that the magnetic features represent dike swarms that served as feeders for these mare basalts, as evident from the location of the Thom- son/Mare Ingenii, Van de Graaff, and Leeuwenhoek mare basalts on the two largest mag- netic features in the region. Modeling suggests that the dike zone is between 25 and 50 km wide at the surface, and dike magnetization contrasts are in the range of 0.2 A/m. We theorize that the basaltic dikes were emplaced in the lunar crust when a long-lived dynamo was active. Based on pressure, temperature, and stress conditions prevalent in the lunar crust, dikes are expected to be a dominantly subsurface phenomenon, consis- tent with the observations reported here. -