... 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 posting by a statistician, except one about BEHR . Statisticians are busy and well distracted by other fields with more tangible data sets. ... Comment . ... Entries RSS . ... vlk on [MADS] Parallel Coordinates . ... Entries (RSS) and Comments (RSS) . ...

... The lines ( ) are equations: e.g., theoretical expressions for h/M, the Lamb shift, .. Some data are measured, a lot are derived: mp [kg], me [Mev/c2], .. ... for a `theoryґ for QHE steps rational universal relation to Needs for a `theoryґ for QHE steps rational universal relation to h block known from block input : h e NA h·NA h/me output me µB h block h block h block : the most important da t a h block : the most important da t a watt ballance Avogadro ...

... Updates to HST Standard-Star Fluxes . ... These data are in an STScI data base named CRCALSPEC and have been divided into two categories to help the user understand the origin and accuracy of these flux distributions. ... 1990, ApJS, 73, 413) and Oke (1990, AJ, 99, 1621) spectra are available. Oke (1990) used the DoubleSpectrograph on the 5-m Hale Telescope to obtain these spectra for HST calibration; and these data are identified in the HST data bases by the keyword OBSMODE=OKE DBSP. ...

Next: THE SOURCE LIST Up: Spectral-Line Observing at AO Previous: THE RADAR BLANKER . ... You also need to decide how you want this correction to be applied - to the center of each correlator board or to the four boards as a whole (thereby preserving the topocentric frequency offset between the boards). Typically, this choice depends on whether each board is centered on a known spectral line, or if you are doing a search in velocity space for an object. ...

XMM­Newton CCF Release Note XMM­CCF­REL­199 OM Grisms Calibration: Update A. Talavera, C. H. James October 19, 2005 1 CCF components Name of CCF VALDATE EVALDATE List of Blocks changed XSCS flag OM GRISMCAL 0003 2000­01­01T00:00:00 --- FLUX GRISM1 NO --- FLUX GRISM2 NO --- WAVELENGTH GRISM1 NO 2 Changes The first issue of the OM grisms calibration was based on spectra processed with IDL routines. ... The absolute flux calibration for both grisms has been updated. ...

Next: Examples of Setup Files Up: Setup Files Previous: Setup Files Contents . Over 200 standard setup files have been created, covering many of the normal modes of observing. ... These especially include precisely defined, and somewhat complex cases like the Mark III standard modes (although MarkIII went the way of the dinosaur long ago. ... v '' files: . These are setup files for VLBI observations using VLBA recording formats. ... These are setup files for Mark III observations. ...

... Apache HTTP Server Version 2.4 . Apache > HTTP Server > Documentation > Version 2.4 > Miscellaneous Documentation . ... This page documents all the relevant standards that the Apache HTTP Server follows, along with brief descriptions. ... http://www.rfc-editor.org/errata.php - RFC Errata . ... This document summarizes the history of HTML development, and defines the "text/html" MIME type by pointing to the relevant W3C recommendations. ... HTML documents are SGML documents. ...

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. ...

Next: The Photometric Performance of Up: NICMOS Data Calibration and Previous: Status and Goals of . ... Absolute Spectrophotometric Standards . Absolute Photometry . ... Velocity shifts and Photometry with Narrow-band Filters . ... HST, NICMOS, near-infrared, standards, photometry, calibration . ... In practice NICMOS does not have a set of filters matching any of the standard ground-based photometric bands and this poses a challenge when trying to achieve precise absolute photometry. ...

Open Systems Handbook: A Guide to Building Open Systems . ... This book is designed to provide interested individuals and organizations with an overview of open systems and the work being done to achieve them. ... This section is organized using a descriptive model of an open systems environment developed by the IEEE PI 003.0 Working Group, which is developing the Guide to POSIX-based Open System Architecture. ... Standards for open systems 13 . Chapter 3: The open systems environment (OSE) 15 . ...

... Bojan Nikolic web pages (r. 329) . ALMA . ... The Python path is used when searching for Python modules, i.e., programs written in Python and dynamic libraries that can be loaded into Python. ... All this can be relevant to ALMA data reduction process because the WVR phase calibration program is an external command line program. ... Some notes on Python relevant to ALMA and ALMA data reduction . Python path vs system path . ... Copyright 2005 -- 2016, Bojan Nikolic feedback welcome ...

... Year of the moment of observation 3. Month of the moment of observation 4. Day of the moment of observation with decimals 5. Hour of right ascension (alpha, h) 6. Minute of right ascension (alpha, m) 7. ... Degree of declination (delta, deg) 9. ... Band for magnitude, Band ("-" if not given) ------------------------------------------------------ N Year Day with alpha delta Band sat Month decimals h m s deg ' '' Mag ------------------------------------------------------ ...

This service contributes to the International Service of Geomagnetic Indices (ISGI) of the IAGA . ... The Kp numbers of the previous month are available in tabular format . ... There are available also historical and current Kp and derived indices per anonoymos FTP (see below). ... U.S.A. FTP server: ftp://ftp.ngdc.noaa.gov/STP/GEOMAGNETIC_DATA/INDICES/KP_AP/ . monthly update) . ... contains the monthly Kp / ap tables in a simple text format readable for both humans and computers (*.tab). ...