The sky background can contribute significant Poisson noise in broad and medium band filters, and must be taken into account during noise calculations. The actual sky b1rightness depends on the heliocentric ecliptic coordinates (latitude and longitude) in a manner summarized in Table 6.3 . ... 22.4 . ... Values for other filters or sky brightnesses can be computed from Table 6.2 , Table 6.1 , Table 6.3 , and Equation 6.2. Table 6.4: Sky Count Rate per Pixel (P sky ). ...

... We have observed and studied critical supercurrents, Ic, in cross-type Nb-Cu/Ni-Nb junctions with Josephson layers prepared from diluted ferromagnetic alloys. For suitable values of the exchange energy in the ferromagnet and the F-layer thickness we have observed Ic(T) oscillation with vanishing Ic for the definite values of T and dF. ... Critical supercurrents, Ic, in Nb-Cu(1-x)Ni(x)-Nb Josephson SFS junctions with F-layers prepared from ferromagnetic Cu(1-x)Ni(x) alloys have been studied. ...

... ATNF Home . ... About ATNF overview . ... Australia Telescope Steering Committee . ... Australia Telescope User Committee . ... Astrophysics graduate student programs . ... Facilities . ATNF facilities . ... Australian Square Kilometre Array Pathfinder . Murchison Radio-astronomy Observatory . ... Parkes radio telescope . Australia Telescope Compact Array . ... Visiting Parkes radio telescope . Visiting Australia Telescope Compact Array . ... Parkes radio telescope webcam . ...

Visual Discovery of SN 1996X in NGC 5061. ... It was not until the IAU Circular was issued that we found out there had been an independent amateur photographic discovery of this supernova by Kesao Takamizawa of Japan. ... Earlier in the week, 660 galaxies had been observed during two nights we had use of the 40 inch telescope at Siding Spring. ... The supernova in NGC 5061 was first seen with the smaller telescope about 10pm local time on Friday, April 12 (April 12.5 UT). ...

... Science Users Information > Observing with ESO Telescopes > Phase 2 Preparation > Observing conditions . ... Service Mode Philosophy . ... The following definitions of the observing conditions are common between Phase 1 preparation and Phase 2 preparation, as well as between Service Mode and Visitor Mode observations. ... There are additional Service Mode Policies and Service Mode Guidelines regarding the observing conditions. ... Seeing (Phase 1) and Image quality (Phase2) constraints . ... Moon . ...

... For a pulsar search observation, with the two polarizations averaged, a useful rule of thumb can be given for calculating the expected rms noise. If the rms noise, , is expressed in terms of the flux density of the target pulsar, then; . ... Robert Minchin 2012-02-22 ...

... This is possible at modest cost due to the low moments of inertia of the telescope and enclosure. ... This same performance will be achieved in higher winds when the telescope enclosure is facing away from the wind, or by using wind screens. ... The telescope system (MILT) will be remotely operable with an on-site operator's assistance by an astronomer located at one of the ARC member institutions. ... Mean Wind Speed . ... Offsets > 10 deg: 1 arc sec rms max . ... 5 sec max, tracking to tracking . ...

Next: The ESO VLT CCD Detectors Software . ... Up: Instrument-Specific Software . ... The framework for data calibration and analysis of the VLT instrumentation is presented, based on the concepts of a calibration plan, pipeline calibration, quality control, and archiving of calibrated data for a ground-based observatory. ... Quality Control Pipeline provides quality assessment for instrument performance data and observing conditions, and tests the results of the Reduction Pipeline. ...

... Armagh Observatory, College Hill, Armagh BT61 9DG, +44 (0)28 3752 2928 . ... Line contribution function for Si IV 1394 ? ... in cm тИТ3 s тИТ1 at ionization equilibrium and for transient ionization. ... Methods We use the Atomic Data and Analysis Structure (ADAS) to calculate line contribution functions for two lines, Si IV 1394 ? ... Thus the ratio of these two lines, which can be observed with the Interface Region Imaging Spectrograph, can be used as a diagnostic of transient ionization. ...

... HOME . ... Richard J. Edgar, Project Scientist . DXS, the Diffuse X-ray Spectrometer instruments were flown on the STS-54 mission of the Space Shuttle Endeavour in January of 1993. ... A Summary of the First Results from the Diffuse X-ray Spectrometer Experiment . ... In January of 1993 the Diffuse X-ray Spectrometer (DXS) instruments flew on the STS-54 mission of the Space Shuttle Endeavour. ... The DXS x-ray spectrum from the diffuse background in the constellations of Puppis and Auriga. ...

... Tonight's Sky . ... Sky this Month . ... milky way . ... The Sky This Week: April 1 - 10 . ... Sky this Week . ... Astronomy for Kids . ... Sky Events . Get to Know the Night Sky . ... Is there any way photons could contribute to the mysterious dark matter? ... Get instant access to subscriber content on Astronomy.com! ... If you are already registered on Astronomy.com, please log in below. ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter. ...

Abstract -- Calculations are performed for the linear polarization of starlight due to extinction by aligned dust grains when the starlight traverses a medium with irregular magnetic fields. This medium is intended to represent the optically thick components of interstellar clouds which are observed to make little, if any, contribution to the polarization of starlight. ...

... Astrophysics Group . ... Integration of the NIRSpec instrument . ... SKA AAVS0 array . ... One of the major milestones for the James Webb Space Telescope (JWST) has been, in September 2013, the completion by ESA of NIRSpec, the first multi-object spectrograph to be operated in space. ... Cambridge, and in particular the Cavendish Astrophysics Group and the Kavli Institute for Cosmology, is heavily involved in NIRSpec by hosting one of the Instrument Science Team members (R. Maiolino). ...

... Assured of a reliable method of solving the normal equations, we now consider the equations of condition. The observed magnitude m of a star at M air masses with true instrumental magnitude is modelled as ([ 10 ], [ 28 ]) . ... The effective extinction coefficient depends on the effective spectral gradient [ 29 ] of the star, for which we use some color index, affected by half the atmospheric reddening ([ 26 ], [ 10 ]): . ... Thus, for the B band of UBV, we use the (U-V) color. ...

... 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. ...

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. ...

... Where we have just a single image we assume a probabilistic mode of source detection such that, at a given image pixel, if the probability that the observed value at that pixel could have arisen through statistical fluctuation of the background at that pixel lies below a certain limiting probability , the pixel is considered to contain a source. In XMM practice it is likelihood rather than itself which is employed; in this case the detection criterion is for to exceed the cutoff . ...

... Meade Instruments Corporation . ... Refracting telescopes (Meade Models NG-60, NGC-60, DS-2070AT, ETX-70AT, LXD55-AR5, LX55-AR6 ) and mirror-lens telescopes ( ETX-90AT, 105AT, 125AT, LXD55-SC8, 8LX90, LX200 GPS Series ) are generally more versatile in a wide array of land and astronomical applications. ... The intermediate-level observer, or the non-casual telescope user who wishes to purchase one telescope for a lifetime, should consider a Meade Model LXD55 series, 8LX90, or LX200GPS. ... Meade 4M ...

... 172 ] Briefly, the count rate at the detector from a source at a redshift z is . ... Figure 55 shows the ``Green functions'' for the double compact binary merging rate   evolution assuming no collapse anisotropy. ... Another way that diverse peculiarities in the - distribution induced by the sources evolution could arise is connected with a possible non-monotonic character of the star formation rate in galaxies. ... 22 ] Figure  56 shows two-dimensional cuts through the parameter space. ...

... astro-ph . ... Whitespace-separated words are treated as AND ed. Show 10 50 100 articles per page in Full Compact mode . ... Quasar Variability in the Framework of Poissonian Models . ... It is shown that in this very general framework the well established anti-correlation between variability amplitude and wavelength can only be understood as an effect of an underlying spectral component which remains stable on long time-scales, and is redder than the variable component. ...