Next: Prior Models Up: Prior Models and the Previous: Bayesian Paradigm . The observed image differs from the true brightness distribution in having been blurred and encountering statistical noise in the recording process. ... Let us describe the noise models. ... This model can be approximated, at least for high brightness values, by the Gaussian distribution . ... The noise model we will use in this paper is Poissonian; see Molina and Ripley (1989) for the use of robust Gaussian noise models. ...

True Color Image Gallery: Galactic SNR | Magellanic Cloud SNR . ... Radio Images Page . ... Exposure uf . ... 10102 . ... Exposure uf Exposure time of unfiltered event file . Exposure f Exposure time of filtered event file . ... Click left mouse button on hyperlink below to download file . ... Event 2 FITS File . ... AUX file . ... see fit detail page for more about the fit. see chandra spectrum page for region used. Images in Several Energy Bands . True Color Image . ... 1.0" . ...

... Using a simple 2-D Gaussian Point Spread Function (PSF) on a constant (flat) sky background, I derive a theoretical photometric and astrometric performance model for analytical and digital PSF-fitting stellar photometry. ... The photometric performance is maximized when either the effective background area or the effective-background-level measurement error is minimized. ... An important, but frequently ignored, noise source is the uncertainty of the measurement of the effective background level ( )...

Zero Point and Colour Transformation Zeropoint Definition ffl Throughput is stable (LBB227 25/02/00 r39 vs 25/08/00 r131) ffl Throughput fudged using LBB 227 and BPM16274 measurement ffl Vega observation simulated ffl Simbad literature survey, average brightness / colour : -- m V = 0.03 -- B­V=0.00 -- U­B=0.005 ffl zero points fixed based on simulated Vega observation (cts/sec) -- U, B, V ...

... 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. ...

Next: Calar Alto 2.2m observations Up: Spectral observations and data Previous: Spectral observations and data . ... A 2'' diameter circular aperture was centered on the brightest part of the target galaxy or on the star-like candidate, and a similar aperture was placed 20'' off along the direction zenith-nadir to accumulate simultaneously the night sky spectrum. ... Next: Calar Alto 2.2m observations Up: Spectral observations and data Previous: Spectral observations and data root . ...

B?rbel Koribalski (ATNF) + HIPASS and ZOA teams . The properties shown below were derived from the measurd HI properties. Displayed here are the Local Group velocities of all sources from -300 to +8000 km/s (bins are 100 km/s). Displayed here are the distances of all sources (assuming Ho = 75 km/s/Mpc). ... Displayed here are the HI masses of all sources (assuming point source distribution). Extended galaxies and pairs/groups need to be re-measured. ...

... Armagh Observatory, College Hill, Armagh BT61 9DG, +44 (0)28 3752 2928 . ... Lower panel: The ME spot map of the star in orthographic projection, showing the disc of the star as it would be seen by an observer on the Earth at the labelled rotation phases (see the text). ... We carried out high-resolution spectroscopy and BV(I)C photometric monitoring of the two fastest late-type rotators in the nearby Pictoris moving group, HD 199143 (F7V) and CDтИТ64 1208 (K7V). ...

Physical and dynamical parameters of particles in outbursting Comet 17 P/Holmes . ... The time depending offset between the center of brightness and center of mass of the comet nucleus has been determined on the ground of positional observations of the comet. ... The motion of these particles allowed subsequent offset between the center of brightness and center of mass of the comet nucleus to be obtained from positional observations. ... comet, dynamical model, outburst, brightness. ...

In this gallery are many images of Low Surface Brightness Galaxies which have recently been discovered and analyzed. ... The central surface brightness of this galaxy is 24.28 . Malin 2 This galaxy is another huge disk galaxy with a scale length of 15 kpc and a redshift of 15000 km/a. The high surface brightness knot in one of its spiral arms actually has the same color, luminosity and H-alpha equivalent width as the entire Large Magellanic Cloud . ... Truly it is a Low Surface Brightness Galaxy. ...

A computer controlled low light photometer for nightglow observations. Hardware units of portable photometer for low light measurements, especially night glow emission is described. ... Interface card contain three channels of 24 bit counter, 4 channels of 12 bit ADC and the buffer bus for the controlled motors of the altazimuthal fork mounting and filters wheel, the position encoders. ... Where N( ) is output signal photometer generated input light flux F( l ) . ... PMT # . 599 . ...

... Let us first find out which way -- rise in spectral resolution with some loss in the S/N ratio or increase in the S/N ratio with a fixed spectral resolution -- is better for the purpose of reduction of equivalent width determination errors. ... N -- number of counts for 1 ? ... line equivalent width, . ... Thus if the spectral resolution is managed to be increased (i.e. to decrease )without loss in the number of counts falling at 1 ?, the equivalent width measurement error is then proportional to . ...

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... Bojan Nikolic web pages (r. 329) . ... From astromap version 1.5b3, the OOF software supports deconvolution of an observation of a planet to retrieve the assumed Gaussian parameters of the beam. This deconvolution can be useful for empirical monitoring of telescope beams over time over which the planets used as sources vary significantly in size. ... Bojan Nikolic <b.nikolic@mrao.cam.ac.uk> # Initial version 2005. ... Copyright 2005 -- 2016, Bojan Nikolic feedback welcome ...

... R-band images obtained at 0.8 arcsec seeing conditions have allowed us to separate foreground star from point-like extragalactic source and estimate their brightness separately. ... To study the nature and properties of the source, we observed it under high spatial resolution. ... CONCLUSION RTT150 optical observations with sub-arcsecond seeing and low resolution spectra confirm the hypothesis of superposition of a radio source onto a `normal' F/G galactic star proposed by [1]. ...

Next: Amplitude Distribution Previous: Gravitational Wave Background from . To get rid of the extragalactic GWB produced by binaries, one can use the above considerations to find the optimal detector halfwidth and frequency for observations. ... for the flat red end of the GWB, and . ... Equating to unity, one finds the critical detector halfwidth . ... In contrast, by observing the sky with a GW detector with a narrow enough halfwidth , one will not ``see'' the extragalactic GWB at frequencies . ...

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... About 10% of the time is allocated to moving the telescope to the zenith and exchanging the spectrographic cartridges. ... Focus telescope (open-loop)* . ... TOTAL TIME (seconds) . ... This assumes two 60 second arc exposures and two 55 second readouts. ... Otherwise, the arc exposure will likely consist of a 30 second integration followed by a quick 28 second readout, half the normal time. ... The flat-field exposure can be read out with a quick 28 second readout, half the normal time. ...

. Please standby and you will be automatically connected to the new location of the unframed Supernova page. Or, click on the link above. If you have questions or problems, please email me at David Bishop dbishop@vhdl.org . Last modified: Mon Aug 27 12:40:15 EDT 2001

... Dwarf Planet, Bright Spot . ... Now at Ceres, Dawn's camera recorded this closer view of the dwarf planet's northern hemisphere and one of its mysterious bright spots on May 4. ... The Magnificent Horsehead Nebula . ... Two Worlds One Sun . ... How different does sunset appear from Mars than from Earth? For comparison, two images of our common star were taken at sunset, one from Earth and one from Mars. ... MyCn18: An Hourglass Planetary Nebula . ... Gravitational Anomalies of Mercury . ...