... Near Infrared Camera and Multi-Object Spectrometer Instrument Handbook for Cycle 17 > Chapter 4: Imaging > 4.7 The Infrared Background . 4.7 The Infrared Background . ... Most of the background between 1 and 2 ? ... All three NICMOS cameras carry broad-band filters which are centered on this wavelength. ... Figure 4.17: HST Background as seen by NICMOS. ... The Exposure Time Calculator tool on the STScI NICMOS WWW page also produces background count rates for any filter/camera combination. ...

... The J, H and K bands are characterized by a bright background, such a background is mainly due to the emission of atmospheric lines and of thermal radiation. ... If the source cover a large fraction of the slit, spectra off-source must be observed to adequately sample the sky background. ... The on chip integration time (time spent in each position of the slit) must not exceed 40 seconds in J and H bands and 60 seconds in K band. ... We suggest a sequence of 10 for each elementary integration time. ...

... My source shows only 5 counts in a short 5 ksec Chandra exposure. ... We calculated the significance of observing 5 counts given the expected background counts of 0.1 using spfunc.gammp(5,0.1) =8e-8. ... I believe more fine tuning in computing this p-value is necessary but I wish to address that computing the p-value assuming Ho: background counts=0.1 vs. ... For a given rescaled background (b/50), the p-value is the probability that the counts in the source region can exceed the observed counts. ...

... ATNF Home . About ATNF . ... About ATNF overview . ... Governance overview . Australia Telescope Steering Committee . ... Parkes radio telescope . ... Information & tools for observers . ... Online Resources . ... Visiting Parkes radio telescope . ... Parkes radio telescope webcam . ... Recently, the OGLE team have reported a clear quasar microlensing signal in Q2237+0305. ... From light-curve fitting, I unambiguously set the source size of Einstein Ring radius as a conservative limit. ...

... Fitting the observed dependence includes calculations of the polarization cross-sections averaged over particles orientation and size distribution, their normalization and the comparison of obtained dependencies with Serkowski's curve representing observational data for a chosen star. ... Variations of the polarization factors with wavelength are shown in Fig. 16 for homogeneous spheroidal particles with PF orientation. ... The distinction between prolate and oblate spheroids is also clearly seen. ...

... Science Activities > PhD Thesis Topics offered by ESO Faculty Members > Thesis Topic: Foreground emission and Cosmic Microwave background intrinsic anisotropies . ... Since its discovery the Cosmic Microwave Radiation (CMB) has been one of the pillars of modern Cosmology. ... Further development of this work is the application of already tested algorithms to disentangle the foreground emission from the CMB maps and the determination of the CMB intrinsic emission. ... Return to list of thesis topics ...

... The improvement will be more pronounced in our crowded Wide Field Camera (WFC) images, and may be increased further through use of a more sophisticated method of combining the individual dithered images. Our analysis allows us to check for point spread function shape variations in the HST Planetary Camera (PC) field. ... In crowded field images, we are deriving information about the faint end of the luminosity function (LF) from the texture of the image background. ...

... Galaxies 99 Cosmic background with model of cloudy interstellar medium Yu. ... Figure 1: Averaged spectrum of the cosmic background I f in frequency range 0.25 200 MHz for the Galactic poles. ... First interpretation of the cosmic noise background spectrum at broad band frequency range 0.25 200 MHz with a model of the cloudy interstellar medium ISM is presented here. ... Synthesized background spectra I f for regions of the Galactic poles at the frequency range 0.25 200 MHz is presented in Fig. ...

In 2007-2008, the planet Uranus will reach one of its annual equinoxes for the first time since 1966. As a consequence, its five major satellites orbiting in the equatorial plane will undergo a season of mutual eclipses and occultations very similar to the one that Jupiter's Galilean satellites undergo every 6 years. ... Some of these events occur when Uranus is at conjunction, or the satellite is transiting or too close to the limb of the planet. ... Complete table of events . ...

The problem of solar wind data correlation for the observations onboard several spacecraft is very important for three points of view: . ... This problem is studied now in detail by systematic determination of ion flux and ion velocity data correlations by INTERBALL-1 (IKI group), WIND and IMP 8 (both - MIT group). ... Solar wind plasma correlation lengths from IMP 8, WIND and INTERBALL-1. ... Correlation of solar wind observations onboard several spacecraft: INTERBALL-1, IMP 8 and WIND data. ...

Next: Extragalactic Gravitational Wave Background Previous: Transparency of the Stochastic . Let the sky be observed with a detector having a pencil beam diagram across. The number of stars per frequency decade that is swept by the detector is a function of celestial coordinates (say, galactic coordinates l , b ): . ... It is clear from the figure that for an all-sky detector the Galaxy becomes transparent above the frequency  Hz. ...

Next: Smoothing spline interpolation Up: Background Definition Previous: Background Definition . Background points are used to approximate the observed background by a polynomial of two variables, sample and line numbers, as: . The background of flat field images is usually well modelled by a 2D polynomial of degrees 3 and 4 in variables sample and line respectively. ... For object exposures the signal--to--noise ratio is normally much lower, as is the actual background level. ...

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... We will consider the rms, (K), for observations with a receiver of system temperature, T , frequency resolution, per polarization, and total integration time per observing cycle, . ... For ``in-band'' frequency switching, the line under investigation is always in the observing band. ... Position Switching or ``Out-of-Band'' Frequency Switching: Here the line is only observed for one half of the time, with noise being present all of the time. ...

Astronomy Picture of the Day . ... 4.09.1996 . ... Credit: NASA , IfA ( U. Hawaii ), Photograph courtesy of Bill Keel ( University of Alabama ) Explanation: Above, NASA's Infrared Telescope Facility (IRTF) poses in front of a starry background. Located on top of Hawaii 's towering volcano Mauna Kea , the IRTF is the premier telescope for observing in near infrared light. ... September 1996 . ... 1995 1996 . ... U. Based on Astronomy Picture Of the Day . Publications with keywords: infrared . ...

... Exposure Time Calculator (ETC) . ... ESO - Public Surveys . ... the recommended values to use for DIT, . ... Detector on-chip integration (DIT): seconds. to your chosen value - a separate page gives recommended values to use for DIT - for modes 1 and 2 below you may wish to start with the maximum recommended values as these will minimize the effect of read noise (a total object exposure of Y secs with DIT=X secs will produce Y/X lots of read noise) and give you a lower limit on the time needed. ...

THE PARAMETERS INVOLVED IN HAPKE'S MODEL FOR ESTIMATION OF THE COMPOSITION OF THE EJECTA LUNAR TERRAINS. ... In the previous papers we were estimated the surface roughness of the ejecta lunar terrains by means comparison of the local phase function and the average integrated lunar indicatrix. ... The Hapke's theoretical model of the lunar surface reflection. ... For THE PARAMETERS INVOLVED IN HAPKE'S MODEL: S.G. Pugacheva, V.V. Shevchenko a low-albedo lunar surface parameter Bo = 1. ...

The Hubble orbiting telescope. The Earth's atmosphere, while transparent to visible light, absorbs most "electromagnetic radiations" which belong to the same family as light: parts of the infra-red (IR) and all of the ultra-violet (UV), X-rays and gamma rays. ... The Hubble telescope , in low Earth orbit, overcomes such limitations, in the visible range and in part of the UV. ... Some satellites specialize in observing the Sun, such as the Japanese Yohkoh and NASA's SOHO . ...

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