... The FOC suffers from various types of background, the most important of which are thermal electrons, Cerenkov radiation from high energy particles, geocoronal emission lines, zodiacal light, and light scattered within HST from the bright Earth or Moon. ... From on-orbit measurements using the f /96 camera, the former background has been found to vary with solar zenith distance (ZD); see Sections 6.4, 6.5, and 7.0 of the FOC Instrument Handbook , version 7.0, for more details. ...

... This paper describes the main algorithms used by the Einstein Level One processing to create the exposure masks and the background maps for Einstein IPC images, and how these algorithms were recreated in the IRAF environment. Our goal was to recreate the algorithms used by the Level One Processing to create exposure masks and background maps for Einstein Image Proportional Counter (IPC) data (cf. sections 2.5 and 2.7 of Harnden et al. ...

PCA Calibration Status · Calibration of the Rossi X-ray Timing Explorer Proportional Counter Array Jahoda, Markwardt, Radeva, Rots, Stark, Strohmayer, Swank, and Zhang, 2006, ApJS, 163, 401 ­ Energy : residuals 1% (E 10 keV ); 2% (below 20 keV ) ­ Background: (excess variance)1/2 2%/channel on time scales 1600 sec · ~ 1% (2-10 keV ); ~ 0.7% (10-20 keV ) ­ Timing: ...

... In the three intervening decades there have been many observations of this diffuse emission over a wide range of x-ray energies. ... During the 1970's researchers at the University of Wisconsin, lead by Dr. William Kraushaar, used a series of sounding rocket flights to map the diffuse x-ray emission from the sky in several bands. ... University of Wisconsin Sky Survey map of the B-band (0.13-0.188 keV) x-ray intensity. ... University of Wisconsin Sky Survey map of the 2-6 keV band x-ray intensity. ...

... 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. ...

... 781Seward Einstein data for SNR are available as images on magnetic tape or diskette and as tables of counting rates. ... Unresolved X-ray Sources within or nearby the Cataloged Supernova Remnants The smoothed (or deconvolved) images are available in FITS format. ... The rates (after background subtraction) given in table 2 (and 3) apply to the entire energy range of the IPC (pulse-height channels 1 to 15). Rates are also integrated over the entire IPC or HRI field of view. ...

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. ...

... Usually, H I is seen as bright emission against a darker background, but under the right viewing conditions, it can also be seen as dark absorption against a brighter background. In the case where the background is itself H I emission, the hydrogen is said to be self-absorbed, and the radiative transfer process is termed H I self-absorption (HISA). ... Shown below is a single CGPS H I 21cm spectral line channel at a radial velocity of -41 km/s in the Local Standard of Rest, at l =140њ, b =+1њ. ...

... Amazingly detailed, this false-color x-ray image is centered on the galaxy Cygnus A. Recorded by the orbiting Chandra Observatory, Cygnus A is seen here as a spectacular high energy x-ray source. But it is actually more famous at the low energy end of the electromagnetic spectrum as one of the brightest celestial radio sources. ... With brilliant Venus above the western horizon at sunset and Jupiter and Saturn high in the east by early evening, November's night sky is filled with bright planets. ...

. 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

... They worked out that first magnitude was on average 100 times brighter than the 6th magnitude star. ... This formed an equation of apparent magnitude Mv which is: Mv = -2.5 log f + constant were f is the flux of that star f = ( counts/ exposure) The images that we worked on were taken by the Polar Bear Telescope. ... One of these being that it will be combined with standard stars, which will be used to identify the area of stars and to also help identify other stars within the image. ...

... 2009 August 23 . Giant Cluster Bends, Breaks Images . ... Many of the brightest blue images are of a single, unusual, beaded, blue, ring-like galaxy which just happens to line-up behind a giant cluster of galaxies. ... A gravitational lens can create several images of background galaxies , analogous to the many points of light one would see while looking through a wine glass at a distant street light. ... A blue smudge near the cluster center is likely another image of the same background galaxy. ...

You Can Make Stellar Images Brighter . Articles | ... A few months ago I wrote an article titled "You Can’t Make Them Brighter". So why am I now writing that you can make them brighter. ... The image of a focused star is actually a small disk called the Airy disk, named after the 19 th century scientist Sir George Airy. ... For a given aperture, a smaller Airy disk means that the light is focused to a smaller disk and is therefore brighter. ... www.astronomy.net . About Astronomy Net | ...

... About ATNF overview . ... Australia Telescope Steering Committee . ... Australia Telescope User Committee . ... Facilities . ... Australia Telescope Compact Array . ... Australia Telescope Online Archive (ATOA) . ... Computing: Getting started guide [internal access] . ... ASKAP Home . ... 29 January 2016 . The solar power station for CSIROтАЩs Australian SKA Pathfinder (ASKAP) telescope has been powering ahead at the Murchison Radio-astronomy Observatory in Western Australia throughout January. ...

... Flux density at 1 GHz (/Jy): 19 . ... Notes: This is the remnant of the SN of AD 1006. ... Optical: Filaments to the NW, with broad H component. ... Point sources: The background Schweizer Middleditch star is near the middle of the remnant. ... van den Bergh 1976, ApJ, 208, L17. Optical observations. ADS . ... X-ray spectroscopy. ... Schweizer & Middleditch 1980, ApJ, 241, 1039. ... Optical spectroscopy of the Schweizer Middleditch star. ... Optical spectroscopy. ... 2013, A&A, 552, A9. ...

T he Siding Spring Survey (SSS) is a Near-Earth Object search program that utilises the 0.5-m Uppsala Schmidt Telescope at Siding Spring Observatory, N.S.W., Australia. ... The mission of the Siding Spring Survey is to contribute to the inventory of near-earth objects (NEOs), or more specifically, the potentially hazardous asteroids (PHAs) and comets (PHOs) that may pose a threat of impact and thus harm to civilization. ... Based on the CSS Mission page . ... Siding Spring Survey Main Page . ...

... This program was created for correlating chosen regions in the series of fts images. ... Chosen regions' . ... In this section the program counts the integral for each region of the grid for each image. ... As a matter of fact, the integral is total brightness of the region and it is counted by 'int_tabulated' IDL function. ... In addition, the program will show the count of the regions which correlate with the corresponding region (the brighter region means the bigger count) and its contour. ...

Next: Gravitational Wave Background from Previous: Galactic Gravitational Wave Background . ... It is intuitively clear that at frequencies above the critical ones for our Galaxy, one will detect rare bright jerks produced by coalescing white dwarfs   (at a rate of 1 per 100 year) and NS (at a rate of 1 per - year) in our Galaxy, against a background of the extragalactic stochastic GW. ... Firstly we consider GWB from close individual galaxies, and then will discuss overall extragalactic GWB. ...

... Bad Astronomy . ... Bitesize Astronomy . ... Last week's Snack talked about how black holes can affect the environment around them in such a way as to be very bright . ... It's a common misconception that black holes always have matter swirling into them. ... As this matter gets closer and closer to the black hole it piles up and a large, fairly flat disk forms. This is called the accretion disk , because matter from this disk accretes (that is, falls in) on the black hole. ... 2008 Phil Plait. ...

... The Galactic low-mass X-ray binary GS 2023+338 was discovered during the burst on May 22, 1989 with the Japanise satellite Ginga (aka Galaxy). The flux reached 17 crabs (this unit of flux measurement is an bright X-ray source, Crab Nebula) at 10-35 keV. ... No other radio telescope worldwide carried out multi-frequency measurements. ... Upon 14 days the radio flux fell below the detection level at the RATAN-600 in relation to the decrease of the X-ray flux. ...