20 research outputs found
LSST Science Book, Version 2.0
A survey that can cover the sky in optical bands over wide fields to faint
magnitudes with a fast cadence will enable many of the exciting science
opportunities of the next decade. The Large Synoptic Survey Telescope (LSST)
will have an effective aperture of 6.7 meters and an imaging camera with field
of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over
20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with
fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a
total point-source depth of r~27.5. The LSST Science Book describes the basic
parameters of the LSST hardware, software, and observing plans. The book
discusses educational and outreach opportunities, then goes on to describe a
broad range of science that LSST will revolutionize: mapping the inner and
outer Solar System, stellar populations in the Milky Way and nearby galaxies,
the structure of the Milky Way disk and halo and other objects in the Local
Volume, transient and variable objects both at low and high redshift, and the
properties of normal and active galaxies at low and high redshift. It then
turns to far-field cosmological topics, exploring properties of supernovae to
z~1, strong and weak lensing, the large-scale distribution of galaxies and
baryon oscillations, and how these different probes may be combined to
constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at
http://www.lsst.org/lsst/sciboo
Parasitic fauna of domestic cavies in the western highlands of Cameroon (Central Africa)
Image Degradation Due To Assembly And Alignment Errors In Conical Foil X-Ray Telescopes
The technology to fabricate and assemble many concentric, nested conical foil x-ray telescopes for high-throughput, moderate-resolution, spectroscopic applications promises to be a cost-effective alternative to the grinding and polishing of conventional grazing incidence Wolter Type I telescopes. The three fundamental mechanisms that degrade achievable resolution for any imaging system are diffraction, geometrical aberrations (due to residual design errors, surface figure errors, and alignment errors), and scattering due to residual optical surface irregularities. A detailed parametric analysis of the image degradation due to each of these mechanisms is presented, with particular emphasis on the assembly and alignment errors for these tightly nested conical foil x-ray telescopes. A detailed error budget tree is then developed from which assembly and alignment tolerances can be derived. This error budget tree allows systems engineering trade-offs between foil surface tolerances, assembly and alignment tolerances, and the intrinsic resolution due to diffraction and residual design errors (the conical approximation to the ideal paraboloidal and hyperboloidal surface figure). Although the Danish Space Research Institute\u27s XSPECT conical foil x-ray telescope design parameters were used in this study, the methodology developed is applicable to any nested array of grazing incidence x-ray telescopes. © 1996 Society of Photo-Optical Instrumentation Engineers
