... Stellar Evolution is driven entirely by the never ending battle between Pressure and Gravity . As imbalances are reached, the star is driven to find a new Energy source. ... Pressure and gravitational forces are equal, the star is stable and its core is sufficiently hot to fuse Hydrogen into Helium More about main sequence stars . ... The luminosity generated by the core fusion of Helium into Carbon is far greater than the shell luminosity associated with the fusion of Hydrogen into Helium. ...

... The absolute flux calibration of NICMOS will be calculated from observations of standard stars with known flux distributions F( ). ... In order to expand the set of IR standard stars in the appropriate flux range for NICMOS, M. Rieke, R. Thompson, and collaborators at the University of Arizona are making photometric observations of solar-analog stars, which will be used to normalize the solar spectrum to the observed IR magnitudes. ... Relative flux references accurate to 1.5% for standard...

Next: Fitting the Blaze Up: Instrument Response Correction Previous: Instrument Response Correction . ... This flux has to be corrected for two effects in order to get absolute fluxes: first, for the echelle blaze effect, and second, for the chromatic response of the instrument. ... The solution adopted in the reduction, using the standard star љ , is to correct for both the blaze effect and the instrument response simultaneously. ...

... The material in "From Stargazers to Starships" meets several important requirements of the national standards. Pages cited below are from National Science Education Standards National Academy Press, Washington 1995. ... For example: the sections on astronomy not only describe calendars and sundials (including their construction), but also the astronomy of the ancient Greeks, including two different ways in which ancient Greeks estimated the distance to the Moon. ...

... The visible power a source emits in all directions is measured in lumens. ... Solid Angle- . ... The solid angle of a light cone is the projected area of the cone divided by the total surface area of the sphere. A solid angle is measured in steradians, where 1 steradian corresponds to the solid angle su btended by a cone of unit slant height and unit projected area. ... Luminous intensity is the flow of luminous energy, or lumens, per steradian. ... This is the rate of flow (lumens) per unit area. ...

... The first step to improve the FORS calibration is therefore to obtain data to allow a computation of the illumination correction across the field. ... Another limitation on the calibration accuracy has been the brightness of the Landolt standards which have forced the use of extremely short exposures introducing small but non-negligible shutter-time errors and also resulting in a very small number of useful standards per frame. ...

Next: Buffer Manipulation Up: Programming in C Previous: Compiler Options . Listed below are nearly all the ANSI C standard library functions. The header file where related definitions are stored are given. These may vary on some systems so check local reference manuals. ... More info can be obtained from online man calls or reference manuals. Buffer Manipulation . Character Classification and Conversion . ... File Manipulation . ... Wed Sep 14 10:06:31 BST 1994 ...

Weaving together Astronomy+Statistics+Computer Science+Engineering+Intrumentation, far beyond the growing borders . ... Posts tagged ?standard procedure? ... statistician learning astronomy ? ... In two years of this slog?s life, there?s no po