نتایج جستجو برای: astronomical telescope
تعداد نتایج: 27854 فیلتر نتایج به سال:
There is tremendous scientific potential in a National Virtual Observatory, particularly for projects that need to mine large databases for rare or unusual objects. However, the NVO will also make an impact on any project, large or small, the requires a mixture of datasets to explore a wide range of astrophysical phenomenon. In this article I discuss the influence of the NVO on research into th...
We have constructed a near-infrared imaging camera which is attached to the prime focus of 105cm Schmidt telescope at Kiso Observatory. The camera is equipped with a 10401040 PtSi CSD array developed by Mitsubishi Electric Co. The combination of Kiso Schmidt and the array gives a wide eld of view of 18:4 0 18:4 0 with a reasonable spatial resolution of 1:06"=pixel. The system performances of th...
In radio telescope arrays, the complex receiver gains and sensor noise powers are initially unknown and have to be calibrated. This can be done by observing a strong astronomical point source. Here we extend the calibration algorithms to the case of dual polarized arrays. The algorithms are based on factor analysis and eigenvalue decompositions. We show that a single observation does not provid...
We present accurate measurements of the central wavelengths of 4947 atomic absorption lines in the solar optical spectrum. The wavelengths, precise to a level ∼ 50 − 150 m s −1 , are given for both flux and disc-centre spectra, as measured in relatively recent FTS solar atlases. This catalogue modernizes existing sources based on photographic measurements and provides a benchmark to test and pe...
Clusters of galaxies are expected to gravitationally lens the cosmic microwave background (CMB) and thereby generate a distinct signal in the CMB on arcminute scales. Measurements of this effect can be used to constrain the masses of galaxy clusters with CMB data alone. Here we present a measurement of lensing of the CMB by galaxy clusters using data from the South Pole Telescope (SPT). We deve...
Detailed knowledge of the image of the point spread function (PSF) is necessary to optimize astronomical coronagraph masks and to understand potential sources of errors in astrometric measurements. The PSF for astronomical telescopes and instruments depends not only on geometric aberrations and scalar wave diffraction but also on those wavefront errors introduced by the physical optics and the ...
Directly imaging extrasolar planets using a monolithic optical telescope avoids many pitfalls of space interferometry and opens up the prospect of visible light studies of extrasolar planetary systems. Future astronomical missions may require interferometry for high spatial resolution, but given that the first direct imaging missions will probably fit into a single launch vehicle, the astrophys...
We developed a systematic method for optimizing the design of depth-graded multilayers for astronomical hard-x-ray and soft-gamma-ray telescopes based on the instrument's bandpass and the field of view. We apply these methods to the design of the conical-approximation Wolter I optics employed by the balloon-borne High Energy Focusing Telescope, using W/Si as the multilayer materials. In additio...
A gamma-ray halo in a nearby starburst galaxy NGC 253 was found by the CANGAROO-II Imaging Atmospheric Cherenkov Telescope (IACT). By fitting the energy spectrum with expected curves from Cold Dark Matter (CDM) annihilations, we constrain the CDM-annihilation rate in the halo of NGC 253. Upper limits for the CDM density were obtained in the wide mass range between 0.5 and 50 TeV. Although these...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید