3,945,911 research outputs found
Far Ultraviolot Space Telescope (FAUST)
The Far Ultraviolet Space Telescope is a compact, wide field-of-view, far ultraviolet instrument designed for observations of extended and point sources of astronomical interest. It was originally used in sounding rocket work by both French and American investigators. The instrument was modified for flight on the space shuttle and flew on the Spacelab 1 mission as a joint effort between the Laboratoire d'Astronomie Spatiale and the University of California, Berkeley. The prime experiment objective of this telescope on the Atmospheric Laboratory Applications and Science (ATLAS 1) NASA mission is to observe faint astronomical sources in the far ultraviolet with sensitivities far higher than previously available. The experiment will cover the 1300 to 1800 A band, which is inaccessible to observers on earth. The observing program during the mission consists of obtaining deep sky images during spacecraft nighttime. The targets will include hot stars and nebulae in our own galaxy, faint diffuse galactic features similar to the cirrus clouds seen by the Infrared Astronomical Satellite (IRAS), large nearby galaxies, nearby clusters of galaxies, and objects of cosmological interest such as quasars and the diffuse far ultraviolet background
Research in far ultraviolet filtering for space optical systems
Design and fabrication of multilayer interference filters for ultraviole
Far points and discretely generated spaces
We give a partial solution to a question by Alas, Junqueria and Wilson by
proving that under PFA the one-point compactification of a locally compact,
discretely generated and countably tight space is also discretely generated.
After this, we study the cardinal number given by the smallest possible
character of remote and far sets of separable metrizable spaces. Finally, we
prove that in some cases a countable space has far points
Infrared spectroscopic diagnostics for Active Galactic Nuclei
Infrared spectroscopy in the mid- and far-infrared provides powerful
diagnostics for studying the emission regions in active galaxies. The large
variety of ionic fine structure lines can probe gas conditions in a variety of
physical conditions, from highly ionized gas excited by photons originated by
black hole accretion to gas photoionized by young stellar systems. The critical
density and the ionization potential of these transitions allow to fully cover
the density-ionization parameter space. Some examples of line ratios diagrams
using both mid-infrared and far-infrared ionic fine structure lines are
presented. The upcoming space observatory Herschel will be able to observe the
far-infrared spectra of large samples of local active galaxies. Based on the
observed near-to-far infrared emission line spectrum of the template galaxy
NGC1068, are presented the predictions for the line fluxes expected for
galaxies at high redshift. To observe spectroscopically large samples of
distant galaxies, we will have to wait fot the future space missions, like
SPICA and, ultimately, FIRI.Comment: Proc. of the Winter School "Astronomy in the submillimeter and far
infrared domains with the Herschel Space Observatory", Centre de Physique des
Houches 23 april - 04 may 200
Vestibular modulation of spatial perception
Vestibular inputs make a key contribution to the own sense of spatial location. While the effects of vestibular stimulation on visuo-spatial processing in neurological patients have been extensively described, the normal contribution of vestibular inputs to spatial perception remains unclear. To address this issue, we used a line bisection task to investigate the effects of galvanic vestibular stimulation (GVS) on spatial perception, and on the transition between near and far space. Brief left-anodal and right-cathodal GVS or right-anodal and left-cathodal GVS were delivered. A sham stimulation condition was included. Participants bisected lines of different lengths at six distances from the body using a laser pointer. Consistent with previous results, our data showed an overall left to right shift in bisection bias as a function of viewing distance: suggestive of a leftward bias in near space, and a rightward bias in far space. GVS induced strong polarity dependent effects in spatial perception, broadly consistent with those previously reported in patients: left-anodal and right-cathodal GVS induced a leftward bisection bias, while right-anodal and left-cathodal GVS reversed this effect, producing instead a bisection bias toward the right side of the space. Interestingly, the effects of GVS were comparable in near and far space. We speculate that vestibular-induced biases in space perception may optimize gathering of information from different parts of the environment
The 21st century propulsion
The prediction of future space travel in the next millennium starts by examining the past and extrapolating into the far future. Goals for the 21st century include expanded space travel and establishment of permanent manned outposts, and representation of Lunar and Mars outposts as the most immediate future in space. Nuclear stage design/program considerations; launch considerations for manned Mars missions; and far future propulsion schemes are outlined
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