Results 241 to 250 of about 8,356 (263)

Polarization gratings for visible and near-infrared astronomy

SPIE Proceedings, 2014
We report on the development of polarization gratings that can be used for polarimetry and/or high throughput broadband spectroscopy in astronomy. Polarization gratings are able to overcome fundamental limitations on the diffraction efficiency of conventional gratings to provide near 100% diffraction efficiency over a broad bandwidth.
Max Millar-Blanchaer, Dae-Sik Moon, James R. Graham, Michael Escuti   +3 more
openaire   +1 more source

Limitations of ground based near and far infrared astronomy

Infrared Physics, 1975
Abstract The possibilities of ground based infrared astronomy are discussed. It is shown that telescopes used up to now are not optimized and that the Diffraction Limited Detectivity conditions (DLD) cannot be reached, in the near infrared, by the larger telescopes. The maximum useful diameters for near i.r. and far i.r.
G. Dall'Oglio, I. Guidi, B. Melchiorri, F. Melchiorri, V. Natale   +4 more
openaire   +1 more source

Infrared Spectroscopy of Micro-Organisms near 3.4 μm in Relation to Geology and Astronomy

Astrophysics and Space Science, 1982
Microorganisms sealed in KBr discs have an absorption spectrum over the 2.5-15 μm waveband that shows thermal stability as they are heated in an inert atmosphere to temperatures of about 400 °C. Microfossils tightly sealed within cavities in rocks could be endowed with similar properties of thermal stability.
F. Hoyle, N. C. Wickramasinghe, S. Al-Mufti, A. H. Olavesen   +3 more
openaire   +1 more source

SPIREX-near infrared astronomy from the South Pole

Experimental Astronomy, 1994
Over the next several years we will deploy a series of spectrometers, imagers, and telescopes at the South Pole as part of a project named SPIREX — for South Pole Infrared Explorer. Our goal is to survey a substantial area of the sky to study the origins of galaxies and stars.
openaire   +1 more source

A discussion on infared astronomy - Near infrared night sky background

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences, 1969
Abstract We have carried out near infrared observations on wide fields of the sky, using both a rocket-borne telescope and ground-based equipment. The rocket observations covered the spectral range of 1 to 8 μm. The ground-based observations were carried out in a narrow spectral region around 1.085 μm.
M. Harwit, K. Fuhrmann, M. Werner
openaire   +1 more source

Comparison of shift-and-add and bispectrum image reconstruction methods for astronomy in the near infrared

Journal of the Optical Society of America A, 1996
Using the results of photometry applied to speckle image reconstructions of the triple stellar system LHS1070 in the near infrared, we compare quantitatively the performance of shift-and-add and bispectrum image reconstruction methods and find that comparable results can be obtained.
V. A. Klückers, A. J. Longmore, N. J. Wooder, J. C. Dainty   +3 more
openaire   +1 more source

GNOSIS: An OH suppressing near-infrared spectrograph for astronomy using fibre Bragg gratings

2011 Conference on Lasers and Electro-Optics Europe and 12th European Quantum Electronics Conference (CLEO EUROPE/EQEC), 2011
Astronomical near-infrared spectroscopy is made difficult by the extremely bright and variable night sky background. The night sky surface brightness is more than a thousand times brighter at 1.6µm than at 0.4µm. Furthermore the brightness of the sky changes by factors of ∼10% on time-scales of minutes. Background-subtraction is therefore frustrated by
J. S. Lawrence, S.C. Ellis, J. Bland-Hawthorn, J. Bryant, S. Case, L. Gers, R. Haynes, A. Horton, S. Lee, S. Leon-Saval, H. Loehmannsroeben, S. Miziarski, J. Mladenoff, J. O'Byrne, W. Rambold, M. Roth, S. Smedley, C. Trinh   +17 more
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A discussion on infared astronomy - Near infrared photometry of late-type stars

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences, 1969
Abstract A multi-band photoelectric photometer for observations in the ultraviolet, blue and visible and the infrared bands W (1.06μm), X (1.13 μm, Y (1.63 μm) and Z (2.21 μm) has been constructed and applied to both stellar and planetary observations. The results of photometry obtained for 61 stars are presented.
openaire   +1 more source

Comparison of shift-and-add & bispectrum image reconstruction methods for astronomy in the near-infrared

Signal Recovery and Synthesis, 1995
It is well known that atmospheric turbulence limits the resolution available to ground based astronomical observations to 0.5-1.0 arcseconds in the infrared. The advent of speckle interferometry in the 1970’s [1] has allowed the recovery of diffraction limited Fourier modulus information of astronomical objects of interest to be attempted routinely.
V.A. Klückers, A.J. Longmore, J.C. Dainty   +2 more
openaire   +1 more source

The Mauna Kea Observatories Near‐Infrared Filter Set. II. Specifications for a NewJHKL′M′ Filter Set for Infrared Astronomy

Publications of the Astronomical Society of the Pacific, 2002
A T Tokunaga, W D Vacca
exaly