... Surface Brightness of Background Light . Home . ... Data . ... WFPC2 Home . ... Instrument Home . WFPC2 History . ... LRF Data . ... Data Analysis Home . ... Instrument Handbook . Data Handbook . ... Input the surface brightness in magnitudes per square arcsecond. ... Galaxy U-B and B-V colors are drawn from Longo and deVaucouleurs 1983 for representative objects;V-R and R-I are estimated from WFPC2 Handbook Table 6.1. ... AB_xxxxx are AB magnitudes at the standard WFPC2 filter bands. ...

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. ...

Once students get the hang of it, they can find and measure the brightness of Delta Cephei in a few minutes. ... of Delta Cephei . ... Oct. ... The following table lists the measurements of Delta Cephei made by one amateur astronomer in autumn 1990. ... 4.0 . ... This activity is a simplified version of one that appeared in Hands-On Astrophysics, a series of activities prepared by the American Association of Variable Star Observers with support from the National Science Foundation. << previous page | ...

... Meta Index / Home Page / Source Flagging Algorithms Any source either having a raw count-rate >= 80, or with quality flag bit 4 set (mod-8 pattern) is checked for "close" neighbours, which may be flagged. ... Check each source in the vicinity of the bright source . ... Compute the maximum distance for flagging the source from maxRad = max(exclusionradius, min(70.0, 35.0 * countTable(i) // 80.0) ) If the flagging is done by omdetect, the exclusion radius is determined from the algorithm at the end . ...

... 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 removal of the bright sky background from your IR images is one of the key steps in the data reduction process. Once bad pixels have been removed from all the astronomical frames, the object frames must have the matching sky background images subtracted from them. ... The simplest sky subtraction is where you have separate sky and object frames taken a short time apart. ... The resulting sky subtracted images should be examined to make sure that sky subtraction has been properly achieved. ...

. 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

... 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. ...

... Maps of 21cm emission are dominated by warm H i, and most observations of H i absorption against continuum sources are limited to discrete points. ... Current Results At right are maps of H i emission, HISA, and 12 CO emission in the eastern 25% of the survey, given as projections along the velocity (Figure 1) and latitude (Figure 2) axes. ... 2000, A. J., submitted Figure 1: H i Survey Map (`; b): H i 21cm brightness integrated over all velocity channels; white is bright and black is faint. ...

The night sky brightness, together with number of clear nights, seeing, transparency, photometric stability and humidity, are some of the most important parameters that qualify a site for front-line ground--based astronomy. ... Night sky at ESO-Paranal (Chile). ... Night sky brightness data . ... UBVRI night sky brightness at ESO-Paranal during sunspot maximum (A 2003, PDF) . ... The Dancing Sky: six years of night sky observations at Cerro Paranal (Starlight 2007 conference proceedings, PDF) . ...

Definitions of Magnitudes and Surface Brightness 1 The magnitude system 1.1 Apparent magnitude Astronomers are stuck with the antiquated old system of magnitudes and so a clear explanation of what this system is and how it relates to more sensible units is important. ... 1.2 Absolute magnitude Absolute magnitude is a logarithmic luminosity scale. ... One usually goes by the round about process of referring to the absolute magnitude of the sun. ... Magnitudes and surface brightness 6/6 ...

... 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. ...

... 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 ( )...

Next: Basic Properties Up: R Coronae Borealis Stars Previous: Introduction . RCB stars are named after a star just visible to the naked eye in the constellation of Corona Borealis. RCrB was discovered by Edward Pigott, an English amateur astronomer, who had been observing a star in the `Northern Crown' for over a decade. ... Since 1795, other RCB stars have been discovered and their properties have been carefully observed. ...

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 | ...

... X Ray Moon . ... In this digital picture, pixel brightness corresponds to x-ray intensity. Consider the image in three parts: the bright hemisphere of the x-ray moon, the darker half of the moon, and the x-ray sky background. ... Still, the few x-ray photons which seem to come from the moon's dark half are currently thought to be caused by energetic particles in the solar wind bombarding the lunar surface. ... Publications with keywords: Moon - X-ray - cosmic rays - x-ray background . ...

... Telescope concept . ... The Submillimetron Project is dedicated to astronomical studies at the submillimeter and far infrared wavelengths using a cryogenic telescope located on the Russian segment of the International Space Station (ISS). The Astro Space Center of the Lebedev Institute of the Russian Academy of Sciences is responsible for developing the Submillimetron Project. ... Currently, the Astro Space Center is carrying out a pre-Project study under contract with the Russian Space Agency. ...

Measurement of Sky Brightness at the Iranian National Observatory Davoud Afshari1 and Sadollah Nasiri1,2 1Physics Department, Zanjan University, Zanjan 45195-313, Iran; Institute for Advanced studies in Basic Science (IASBS), Zanjan 45195-1159, Iran; Measurement of light pollution 2 Introduction Among 34 candidate sites at the central part of the country, 5 sites namely Garkesh (in Kashan ), Kolahbarfi(in Kashan ), Deynava (in ... One of these is light pollution. ...

... Appropriate values of DIT the integration time (DIT secs) for each individual integration, are lmited by various considerations. N.B. Ndit individual Integration s each of DIT secs are coadded to form a single Exposure of time Ndit*DIT]. The recommended minimum DIT is one sec (the minimum possible exposure time) or the value at which the noise becomes sky (rather than detector) limited. ... The recommended maximum DIT is such as to keep the detector wells less than half full. ... 40 sec . ...

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. ...