... HST Phase II Proposal Instructions for Cycle 20 > Chapter 3: Fixed and Generic Targets > 3.10 Bright-Object Constraints . ... Non-linearity, saturation, or other temporary effects which may occur at substantially fainter limits than those identified below are described in the Instrument Handbooks . ... STIS . ... ACS . ... These limits have been translated into a table of magnitudes as a function of spectral type for the various configurations and modes ( ACS Instrument Handbook, Table 7.4 ). ...

... 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 ( )...

... 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. ...

... 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...

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 parameter brief (with its actual uncertainty sbrief) is the mean effective surface brightness in B-band , i.e. the mean surface brightness inside the effective aperture (the circular aperture enclosing one-half the total flux). It is expressed in mag arcsec -2 . ... 2) from the mean surface brightness "LV" inside the effective isophote (elliptical isophote enclosing one half the total flux) measured by Launberts&Valentijn (1989) . ... Effective radius . ... HyperLeda . ...

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) . ...

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 | ...

... Figure 1: Data from selected high latitude pointings overlaid in detector co-ordinates. 132ksec total low proton flare conditions, and bright point sources excised . Figure 2: Same data set from selected high latitude pointings but in 0.2-2keV only. ... Figure 3: Same data set from selected high latitude pointings but in 2-10keV only. ... Figure: EPIC MOS data set from selected high latitude pointings plotted as spectra (PATTERNS 12&&#XMMEA_EM), and normalised for approx 1 arcmin square. ...

... Problem 1.1: (4pts) We want to use supernovae as a standard candle to measure luminosity distance as a function of redshift in order to determine the Hubble Constant. ... Problem 2: In a flat Universe, the luminosity distance to an object at redshift z, in a universe made up of i forms of matter each with an equation of state wi and density, i is given by ,1 / 2 z & ) c 3 + 3wi DL = (1 + z) # dz"(% $i (1 + z") + H0 'i * 0 2.1 (5 pts). ... Assume the universe is radiation dominated the whole time. ...

... Zodiacal Light and the False Dawn . ... An unusual triangle of light will be particularly bright near the eastern horizon before sunrise during the next two months for observers in Earth's northern hemisphere. ... X Ray Moon . ... In 1572, Danish astronomer Tycho Brahe recorded the sudden appearance of a bright new star in the constellation Cassiopeia. ... Two months ago, however, Pluto and its large moon Charon passed in front of a comparatively bright triple star system known as P126. ...

ALMA | ... Phase Correction Algorithms | ... On this page, we describe what the phase correction algorithms set out to do and the framework we have developed to optimally use all of the available information. ... We are developing a Bayesian framework to combine all the information we have about the current and future meterological conditions (which are naturally accommodated as priors in a Bayesian scheme) with detailed physical models of the atmosphere. ...

... Outline of the BTF paper by Erwin de Blok (25-2-2002) ----------------------------------------------------- * Description of sample * Data and corrections * Descriptions of method to measure line widths * Description of method to measure inclinations * Corrections to linewidths and magnitudes (inclination, random motion, instrumental resolution, extinction) * Corrections to recession velocities (to Local Group frame, also POTENT etc for nearby galaxies) * Describe B-band ...

... 2006: . ... 1) A study of the solar corona. ... 2) The study of the solar northern polar region. A powerful radio source above the solar North Pole in the region of the polar coronal hole was discovered. ... A transition boundary from brightening to darkening at the wavelength of 3.5cm was found in the emission of the polar coronal hole. These facts are decisive for the choice of the solar cycle model. 3) Polarized radio emission of a high-latitude prominence was registered. ... Archive . ...

... A comparison of the computed and experimental relations F max ( H), as well as comparison of drift scans of point sources across different horizontal cross-sections of the BP with the corresponding computed cross-sections were made. ... The drift scans of the point source 3С84 (H=87 o ) at the wavelength 7.6 cm across the horizontal cross-sections of the BP (black lines) and the computed horizontal cross-sections of the BP corresponding to them (red lines). ...

... 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. ...

Two major reasons: the number of stars isn't really seven (it's many more), and they all have different brightnesses, so that you see more or fewer of them depending on viewing conditions. The brightness of stars is measured on the magnitude scale, where the most prominent stars in the sky are around 1st magnitude, and the faintest you can see with your eye are about 6th. ... I think this makes it quite likely that the list will be truncated at Taygeta, giving six visible stars. ...

. 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

... Radio astronomical tests of the engineering model of the space radio telescope (SRT) were completed in Pushchino - see Results . ... Monitoring of the development of the upgrade on-board 1.35-cm receiver (R-SRT-1.35 cm): . ... EM Engineering Model . ... OHCFS-SRT Space Radio Telescope On-board Heterodyne and Clock Frequency Synthesizer set . OHFS-SRT Space Radio Telescope On-board Hydrogen Frequency Standard . ORFS-SRT Space Radio Telescope On-board Rubidium Frequency Standard . ...