... 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 ( )...

ESTIMATIONS OF EFFECTIVE HEIGHT, SIZE AND BRIGHTNESS TEMPERATURE OF SOLAR CYCLOTRON SOURCES A.N. Korzhavin, T.I. Kaltman Sp ecial Astrophysical Observatory of RAS, Saint-Petersburg, Russia arles@mail.ru The mo deling of microwave emission from a sp ot-asso ciated cyclotron source was done to refine the metho d of estimations of effective brightness temp erature, size and height ab ove photosphere in the pro cessing of RATAN-600 observations. ...

Smithsonian Astrophysical Observatory Memorandum To : From Date: Re: M. Cappi, Strong Gravity SDT/YB Team, XMS team : M. Garcia April 14, 2010 XMS high/mid/low resolution event rates for bright AGN mrg-2010-02v2 This memo arises out of the concern that the bright AGN that will be used to observed strong gravity effects ­ in particular those for which time-resolved measurements of test particle orbits will be made ­ may generate counting rates in the XMS that are sufficient to overwhelm it. ...

The ESA/ESO Astronomy Exercise Series 2 . The Distance to Messier 100 as Determined by Cepheid Variable Stars . ... The small variations in distance to the individual Cepheid variable stars in the Cloud are negligible compared with the much larger distance to the SMC. ... In this way Cepheid variable stars can be used as one of the 'standard candles' in the Universe that act either as distance indicators themselves or can be used to calibrate (or set the zero point for) other distance indicators. ...

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 . ...

... 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. ...

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. ...

... Effective use of large-scale surveys is dictated by the efficiency of detection of the objects of interest. ... It is a stand-alone software package, designed to work with spectral-line FITS cubes and produce source lists and graphical results showing detected objects. ... Figure 2: Example graphical output of Duchamp showing the zeroth moment of each detection, in its appropriate spatial location. ... Innovations in Searching A key aspect of source detection is the application of a threshold. ...

... References: %observed energy levels: Del Zanna and Mason, 2005, A , 433, 731 %theoretical energy levels (second column): Storey, Del Zanna, Mason, Zeippen, 2005, A , 433, 717 (scattering calculation) %theoretical energies (third column): Del Zanna and Mason, 2005, A , 433, 731 (SUPERSTRUCTURE calculation with term energy correction) %produced as part of the Arcetri/Cambridge/NRL 'CHIANTI' atomic data base collaboration % % Giulio Del Zanna - June 7 2005 . ...

... 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...

... 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. ...

... 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...

... 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. ...

... 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 . ...

. 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

... 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. ...

THE PHOTOMETRIC RESEARCHS OF THE MERCURY'S SURFACE BY MEANS OF DIGITAL MODELS. ... The surface brightness of Mercury was measured Danjon (1933, 1949, 1953) and Harris (1961) in phase angle 3o-123o. The analysis of the various data of the integral photometric gives the results of determination of the main photometric constants for Mercury. ... THE PHOTOMETRIC RESEARCHS OF THE MERCURY'S SURFACE: S.G. Pugacheva The surface brightness of the Mercurian images was established on the geologic map Mercury. ...

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. ...

Download Izmccd (~2.7 MB). ... a) a choice of the best mode of measurements of stars and objects ("Properties/Measurement"), . b) a choice of reference stars. ... 1) necessity of presence on an image of a plenty of stars (we recommend to apply this mode, if on the frame of reference stars is more 100) . ... Sx and Sy depend from residuals at all reference stars (reference stars are marked by blue color). ... These residuals are the image of the star a minus function of a profile for each pixel. ...

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) . ...