... We also present independent relationships between the visual surface brightness parameter FV and the colours (V \Gamma R), (V \Gamma I), (R \Gamma I) and (V \Gamma K). We find that (U \Gamma B) and (B \Gamma V ) are unsuitable as T eff indicators. The tightest relationship in each case is found for the (V \Gamma K) index. Our mean relationships agree reasonably well with similar relationships derived by other authors, where such are available. ...

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 . ...

. Next: Diameters Up: Stellar parameters from calibrations Previous: Gravities Contents . Temperatures of stars are derived from their spectral type and luminosity class. Calibrations are stored in files spec_par.V, spec_par.IV, spec_par.III, spec_par.II, spec_par.I in oyster/starbase . teff_stars Compute effective temperature for all stars in startable. teff_star ( spectrum _char ) Function. Return effective temperature for star with specified spectrum. Christian Hummel 2015-04-28

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. ...

... This effect is visible in Figure 4.3 which shows a logarithmic stretch of the image resulting from a 100s exposure on a star of V magnitude 2.6 through filter F502N in the PC. Extreme overexposure of the Loral CCDs is not believed to cause any permanent effects, and therefore the WFPC2 does not have a bright object limit. ... This model only works on very highly saturated stellar images. ... Several other artifacts that are common in saturated stellar images are also obvious in Figure 4.3 . ...

In the PROJECT we are using the following peculiar . features of RATAN-600 . ... Brightness temperature sensitivity being equal to the antenna temperature sensitivity .. ... Receiver system .. ... Using aperture averaging effect. dual- beam and dual (multi-) frequency filtration, we demonstrated full filtration of the atmosphere noise down to the receiver noise at all scales of acoustics peaks ( Fig.1 , Fig 2 ). ... We select this frequency as the central one in our project. ... Antenna surface . ...

. Diameter of circular antenna . 576 m . Number of antenna elements . 895 . Size of an element . 11.4 x 2 m . Geometrical area . 15000 m 2 . Effective area of full circle . 3500 m 2 . Wavelength range . 1 - 50 cm . Frequency range . 610 - 30000 MHz . Maximum angular resolution . 2 arcsec . Accuracy of coordinate determination . 1-10 arcsec . Flux density limit . 0.500 mJy . Absolute brightness temperature limit . 0.050 mK . Tracking time (South sector + Flat mirror) . 1-3 h . [RATAN-600 Homepage]

... 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 ( )...

... The main field of my investigations is stellar spectrophotometry. As a result of scientific activity of our group spectrophotometric catalog was created including energy distribution data on 900 stars in the range 3200-7600AA and 250 stars in the range 6000-10800AA (Voloshina et al., Spectrophotometry of Bright Stars, ed. I.N.Glushneva, 1982, Moscow, Nauka, in Russian). ...

... References: %Observed energy levels (2-5): Kucera et al., 2000, ApJ , 538, 424 % Observed energy levels (6-15): Edlen, B., 1984, Pysica Scripta, 30, 135 % Observed energy levels (n=3): identifications from the X-ray line list by Landi Phillips 2005 , ApJ , in press % Observed energy levels (n=4,5): Shirai,T., Sugar,J., Musgrove,A., Wiese,W.L., 2000, J.Phys.Chem.Ref.Data, Monograph 8 % Observed energy ...

... 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...

... Luminosity (L) · · · · A source's luminosity is the power that it emits in radiation. ... NB Astronomers often say `flux' when they mean `flux density' · SI units are Wm-2Hz -1 -26 filter · Also used are Jy 10 Wm-2Hz -1 E= РРРF d dA dt Specific Intensity, Surface Brightness (I) · Specific intensity (or surface brightness) is the power received (or emitted) per unit area per unit frequency per unit solid angle. ч F at surface of a spherical source = I · · Specific intensity is independent of distance...

... Telescopes ћ Binoculars ћ Microscopes . Meade Ultra-High Transmission coatings (UHTC ) Group . ... Meade Standard Coatings: The optical surfaces of all Meade telescopes include high-grade optical coatings fully consistent in quality with the precision of the optical surfaces themselves. ... These specialized, and extremely advantageous, coatings are offered here as the Meade Ultra-High Transmission Coatings (UHTC) group, a coatings group available optionally on many Meade telescope models. ...

. 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

ATCA ­ Calibration at mm wavelengths Rick Forster University of California, Berkeley Hat Creek Radio Observatory Berkeley-Illinois-Maryland ... Basics of interferometry The atmosphere Amplitude phase calibration Atmospheric instrumental effects Antenna effects 1 ATCA synthesis workshop - May 2003 ATCA Bands Band L S C X K W cm 20 13 6 3 1.2 0.35 GHz 1.5 2.3 5.6 8.6 20.5 87.5 mJy/b 0.19 0.24 0.22 0.21 0.53 2.70 beam 33 22 10 5 2 0.6 ...

Effective Area Analysis using the Chandra HETGS Herman L. Marshall Chandra X-ray Center (MIT) Chandra Effective Area Herman Marshall (MIT CXC) Mallorca Feb. ... 05 13 HETGS Residuals after fixing Ir-M edge Chandra Effective Area Herman Marshall (MIT CXC) Mallorca Feb. ... 05 23 ACIS OBF HETG Efficiency HRMA Effective Area Chandra Effective Area HRMA Ir-M edge · · · Jump is about 10% MEG and HEG agree See Diab Jerius' talk Chandra Effective Area Herman Marshall (MIT CXC) Mallorca Feb. ...

... Since moonshine is really reflected sunlight, the full Moon is on the average slightly brighter in mid-winter, when Earth is closest to the Sun. In addition, the distance of the full Moon also varies, due to the ellipticity ("eccentricity") of the Moon's orbit. On 22 December, 1999, the two effects combined to produce the brightest full Moon of the century. ... This year will be the first full moon to occur on the winter solstice, Dec. 22nd, commonly called the first day of winter. ...

... Credit: STS-82 Crew , NASA Explanation: In low Earth orbit there is not enough atmosphere to diffuse and scatter sunlight, so shadows are black and the sky is dark - even when the Sun shines. The harsh lighting produced this dramatic effect as mission specialist Gregory Harbaugh photographed colleague Joseph Tanner during their second spacewalk to service the Hubble Space Telescope in February 1997. ... February . ... Publications with keywords: Sun - space shuttle - astronaut - dark - sky . ...

THE THERMAL RADIATION OF THE LUNAR SURFACE IN THE IR RANGE OF THE SPECTRUM (10-12 µm). ... 0.80 0.60 0.40 0.20 0.00 -0.20 -0.40 -0.60 -0.80 -0.80 -0.60 -0.40 -0.20 0.00 0.20 0.40 0.60 0.80 Fig.1 0.80 0.60 0.40 0.20 0.00 -0.20 -0.40 -0.60 -0.80 -0.80 -0.60 -0.40 -0.20 0.00 0.20 0.40 0.60 0.80 Fig.2 0.60 0.40 0.20 -0.00 -0.20 -0.40 -0.60 -0.60 -0.40 -0.20 -0.00 0.20 0.40 0.60 0.80 Fig.3 Indicatrix of the thermal radiation of the Moon (10.5-12.5 µ). ...

Subject, Object and Problems of Astrophysics. Practical and Theoretical Astrophysics. ... Visual Telescope; Problems Which Are Solved with the Its Help. ... Resolution of Telescopes. ... Effectiveness of Telescope in Respect of Resolution. ... Optical Power of Telescopes for Star-like and Extensive Objects. Boundary Magnitude. Reasons of Light Dissipation in Telescopes. ... Spectral Instruments in Astrophysics. ... Basic Photometrical Ideas, Magnitudes and Their Measurement. ...