... The task first computes a background image in order to identify pixels that may be part of a source. The task uses two different algorithms for detecting ``point'' and ``extended'' sources. ... If a likely source is found its position and shape parameters are computed by moments and the pixels assigned to the source are set equal to the source number. ... The source is again classified as either ``point'' or ``extended'' from a comparison of its with to that of the PSF width. ...

... In most astronomical observations the image intensity consists of contributions from both object and sky background. Depending on the complexity of the field and the type of object, different methods are used to estimate and subtract the background intensity. ... Non--linear filters are often used to remove stellar images and other sharp features (see Section ) while extended objects are very difficult to eliminate automatically. ...

... WFPC2 ETC for Extended Sources + Background - v4.0 . Home . ... Data . ... WFPC2 Home . ... Instrument Home . WFPC2 History . ... Calibration Home . ... LRF Data . ... Data Analysis Home . ... ETCs . ... Brightness: (mag. arcsec -2 ) . ... Line: Ly 1216 C IV 1550 He II 1640 C III 1907 Mg II 2800 0 II 3727 Ne III 3869 H 4340 0 III 4363 He II 4686 H 4861 0 III 4959 0 III 5007 N II 5755 He I 5876 0 I 6300 N II 6548 H 6563 N II 6583 S II 6716 S II 6731 S III 9531 Specify Z Vel. : (units) . ...

The antenna element Ravi ATNF, Narrabri 1. ... Miriad works out the radio Parabolic reflector: A parabolic reflector adds all the fields from a surface = aperture at a focal point. ... Feeds are `compact' and `corrugated' horns The inner profile is curved The inner surface has grooves Cross-section of a horn Sub-reflector 28 main-reflector Feed horn O `optical axis' The feed horn adds all the rays that come from the 28 deg. wide sub-reflector. The feed down-weights rays that come off-axis. ...

Next: *errcreate* - Use of Up: Background Corrections Previous: *imcalc* - Obtain a . Obtain a radial profile estimating the background level from a background map. input files: xdata$snr.qp; xdata$snr_bbk.imh . intermediate file: broad.imh . output file: broad_cnt.tab . ... Alternatively, the blocking and pi selection can be done as input to the task avoiding the creation of another data file. input files: xdata$snr.qp; xdata$snr_bbk.imh . ...

... 2005 January 11 . Machholz Meets the Pleiades . ... Explanation: Sweeping northward in planet Earth's sky, comet Machholz extended its long ion tail with the Pleiades star cluster in the background on January 7th. ... While the visible coma spans about 500,000 kilometers, the nucleus of the comet, likely only a few kilometers across, lies hidden within . Comet tails can extend many millions of kilometers from the nucleus, but appear substantially shortened because of perspective. ...

Next: Imaging Polarimetry with NICMOS Up: NICMOS Data Calibration and Previous: The Photometric Performance of . ... NICMOSlook and Calnic C . ... Extracting spectra from a large number of NICMOS grism images requires a convenient interactive tool which allows a user to manipulate direct/grism image pairs. ... NICMOSlook and Calnic-C are two programs that were designed to take advantage of the fact that the NICMOS grism mode typically consists of taking both a direct and a grism image. ...

Extended time series of Solar Activity Indices (ESAI) is database including observational, synthetic and simulated sets to study Solar magnetic field variations and their influence on the Earth. ESAI extend the ordinary lengths of some traditional indices of solar activity: sunspot areas, Wolf numbers (equatorial component of magnetic field of the Sun), polar faculae numbers (polar component), mean latitudes, N-S asymmetry of hemispheres (location of activity). Series . ...

Next: Generating Calibration Reference Files with an OPUS Pipeline . Up: Data Pipelines and Quality Control . ... Space Telescope Science Institute, Baltimore, MD 21218 . ... The OPUS pipeline data processing software, developed at the Space Telescope Science Institute (STScI), handles this demanding level of throughput by providing a distributed, concurrent pipeline processing environment for the set of applications that transform the raw telescope telemetry into archival products. ...

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OptInt PmWiki : Pm Wiki / Wiki Style Examples . Wiki styles | ... PmWiki uses WikiStyles for styling text with color and other attributes. PmWiki 2.0 introduced the ability to control the styling further and to even place styles on blocks. ... In addition, an author can define a style "shortcut" by using the define= property. For example, to define a style of %red% , one can use: . define=mystyle color=red% Here is some %mystyle% red text created using a style shortcut. ...

This page will present a review with brief descriptions (incl. refs) of different methods. differential equation methods: . ... extended boundary condition method (EBCM): . homogeneous and multilayered) spheres, finite cylinders, spheroids, Chebyshev particles and so on, incl. non-axisymmetric particles (refs) . ... Rayleigh one (conditions + refs) . Rayleigh-Gans one (conditions + refs) . Anomalous Diffraction one (conditions + refs) . Geometrical Optics one (conditions + refs) . ...