... 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 brightness depends on the heliocentric ecliptic coordinates (latitude and longitude) in a manner summarized in Table 6.3 . ... For many targets LOW-SKY will have minimal impact on the observing efficiency. ... Table 6.4 shows approximate sky count rates for the WFC and PC1 for filters with significant sky count rates. ...

... 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. ...

. 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 Cosmic Microwave Background Radiation Temperature Work in groups of 2-4. ... Due 1999 April 15 In this laboratory exercise, you will use the radio telescope on the roof of Science B to measure the intensity of the Cosmic Microwave Background Radiation (CMBR). ... The output of the telescope when pointing at the sky will then be 2 Tsys = Trec + Tsky : The temperature of the sky can in principle arise from two sources, radiation from the atmosphere and radiation from outer space (the CMBR). ...

Calibration asp ects in the XMM-Newton Slew Survey Michael Freyb erg , MPE · Optical Loading · Pattern Pileup / Pseudo-MIPs · Internal FIFO overflows · Straylight / PSF · Background Michael Freyb erg MPE Garching XMM-Newton EPIC Calibration Meeting , MPE Garching , 04 May 2006 1 XMM-Newton Slew Survey: EPIC -pn · ... 918 ­ 952 CalClosed (first + last slew IDLE) Michael Freyb erg MPE Garching XMM-Newton EPIC Calibration Meeting, MPE Garching, 04 May 2006 19 ...

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 (1797), 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. ...

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) . ...

... 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 background - cosmic rays - X-ray . ...

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 | ...

... Imagine that for every pixel in the color image, you take its luminance value (that's how bright it appears). ... In the end, you will have a histogram which counts how many times each luminance value appears in the image (that histogram can be used to analyze the distribution of the luminance values in the image). ... For the watermark effect, we want to use the same value that we used in the Stretch Contrast step, so that the lightest color will be in fact white (255), and nothing will get clamped...

Appendix C Radiative Transfer for a Two-Level System This appendix details how to derive the total column density of a linear rigid-rotor molecule, such as CO, from the observed brightness of its rotational transition. ... C.2 Radiative Transfer for a Two-Level System I now consider emission in a two-level system from an upper J + 1 (denoted `u') to lower J (denoted `l') state. ... Spontaneous emission is controlled by the A coefficient, with a rate Aul nu . ... Tex exp(-31. ...

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. ...

... 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. ...

... 389Voges+ IX/10A ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1999) ================================================================================ The ROSAT all-sky survey bright source catalogue. ... At a brightness limit of 0.1cts/s (8,547 sources) the catalogue represents a sky coverage of 92%. Broad band images are available for a subset of the flagged sources from http://wave.xray.mpe.mpg.de/rosat/catalogues/rass-bsc . ... 0 Source countrate (4) 70- 78 E9.3 ct/s e_Count ?= ...

This diagram shows the six superimposed "layers" of the CSS table model. This diagram illustrates the algorithm for calculating a cell's final background. ... The diagram shows how, looking down on the six rectangles, one may compute the background color of each cell. ... A cell without a background color in the top layer is depicted as a "window" onto the lower layers, which give its final background color. ...

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 | ...

... 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. ...

... It is found that the correlation coefficients between these two parameters calculated separately inside and outside the sunspot formation zone ±30 have cyclic variation and occur in anti-phase. This suggests different mechanisms of formation of the corona in the fields of small, medium, and large scales. ... The relationship between the coronal green line brightness (CGLB) and the magnetic field strength (MFS) has been investigated by constructing the corresponding synoptic maps for the 1977-2001. ...

... 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. ...

... 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. ...