The WFPC2 cameras have significant geometric distortion which not only affects astrometry, but also affects photometry (because it induces an apparent variation in surface brightness across the field, and hence impacts the flat fields). ... The pixel scale can be estimated from the commanded offsets between the frames (relying on the FGS scale and distortion calibrations). ... The cubic distortion coefficients can be used to derive effective pixel areas as presented in Figure 5.16 . ...

... The are two main sources of magnetospheric electric fields. The other is the solar wind related, dawn-to-dusk directed ("convection") field, and the other is the co-rotation electric field related to the rotation of the Earth along its spin axis. The electric fields have a strong effect on the drift paths of the magnetospheric plasma . ... The energetic particles, following the magnetic drifts more readily, are also affected by the convection field. ... Space Physics Text Book of Oulu ...

Compilation of Surface Brightness . HyperLeda home | Documentation | Search by name | ... Search an object in the surface brightness catalogue . The surface brightness in magnitudes per square arcsec (mag arcsec -2 ) . ... Surface brightness at effective radius . ... Effective mean surface brightness within the effective radius (equivalent radius in which half the total flux is emitted). ... Quality Flag The quality flag has the following meaning: . ... regular measurement . ...

... Astronomers of the SAO together with an international group of scientists have proposed an explanation to the long-standing mystery of why magnetic fields are more common amongst cool white dwarf stars than amongst young and hotter ones. ... As the result magnetic white dwarfs demonstrate excess in their frequencies in the temperature range below 14000K. The authors also show that the strongly magnetic white dwarfs are of the oldest stars of the Galaxy originated from intermediate-mass relic stars. ...

... We also take care to characterise the flat fields, especially their colour dependence, to very high precision which enables high precision photometry even without autoguiding. ... The Blue Diamond Effect The blue diamond effect is caused by surface imperfections on the silicon chip introduced during manufacture, resulting in a repeated large scale pattern in the flat field at blue wavelengths. ... We can remove the blue diamond by using a colour appropriate flat field produced in the lab. ...

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. ...

... Т.И.Голенищева-Кутузова и Ю.Г.Кудряшов планируют провести 4 занятия. ... Задать векторное поле на некоторой поверхности значит нарисовать в каждой точке этой поверхности стрелочку. ... Более формально, в курсе будут рассмотрены примеры векторных полей на плоскости, сфере и торе ("бублике"), доказана теорема Пуанкаре-Бендиксона о том, какие бывают -предельные множества векторных полей на плоскости или сфере, будет дано определение индекса векторного поля и показано, как его применять. ...

... Satellite data ] . SMIS ] . The program is designed to process the specific AVHRR instrument data for calculation and analysis of temperature fields on the sea surface and upper level of clouds. It performs brightness correction for visible channels with regards to clouds altitude. ... The program features a wide variety of classification algorithms (including two-dimensional histogram analysis) and enables to construct personal procedures for classification. ... Back to SMIS Home Page . ...

Next: Radio pulse characteristics Up: An overview Previous: The structure of neutron . Typically Gauss for normal pulsars . Consistent with flux conservation during stellar collapse . ... Gravity dominates stellar structure . B field dominates exterior . Stellar surface is so small that observed emission is dominated by the magnetic field. ... Only field lines inside light cylinder are closed . Particles are constrained move along field lines . ...

... Fields of Minerals on Ganymede . ... 7.11.1996 . ... Credit: NIMS , Galileo Mission , JPL , NASA Explanation: What treasures lie on the surface of Ganymede ? Last week, NASA released a map of Jupiter's largest moon made by the Galileo Orbiter highlighting ice and minerals deposits. The leftmost photograph by Voyager shows surface features in visible light, but the rightmost photograph , taken in infrared light by Galileo, shows the locations of minerals in red and ice grains in blue. ...

... Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. November 7, 1996 . Fields of Minerals on Ganymede . Credit: NIMS , Galileo Mission , JPL , NASA . ... The leftmost photograph by Voyager shows surface features in visible light, but the rightmost photograph , taken in infrared light by Galileo, shows the locations of minerals in red and ice grains in blue. ... About APOD | ...

... 2 Magnetic Field . ... A magnetized bar has its power concentrated at two ends, its poles ; they are known as its north (N) and south (S) poles, because if the bar is hung by its middle from a string, its N end tends to point northwards and its S end southwards. ... That flow became known as an electric current . ... An electric current produced a magnetic force! ... The fund