BASIC EXTRAGALACTIC ASTRONOMY - Part 4: Luminosity Distance, Cosmic Dimensions, Cosmic Magnification
Posted 26 February 2020 - 10:18 AM
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Posted 28 February 2020 - 12:08 AM
Extragalactic Cosmological Calculator, CosmiCalc.exe, is finally finished. It derives a number of physical properties of remote galaxies and quasars based on objective data, such as redshift, apparent magnitude, and apparent diameter. Such data is readily available for all named objects at:
the SIMBAD Astronomical Database, [ http://simbad.u-strasbg.fr/simbad/ ]
and at the NASA/IPAC Extragalactic Database (NED), [ http://ned.ipac.caltech.edu/ ]
The program is based on equations in the CloudyNights.com series of articles titled Basic Extragalactic Astronomy. These equations are accurate within several percent of professional results for extragalactic objects which recede primarily by Hubble flow, or by the expansion of the universe. They will not be accurate for very nearby galaxies, like M31, whose motion relative to us is mostly due to the "peculiar velocity" through space.
The program is free and compatible with all Windows versions. It is self-contained, with no need for INI files or registry entries. It is "portable", which means it can be run from any location in the file system, including the Desktop, or from an external USB drive.
The program can be downloaded from Google Drive at
The source code BAS file can be opened with Notepad, and is available at
The first screenshot is for quasar 3c 273.
The second screenshot is for the distant quasar APM 8279 which is used as an example in the articles.
Suggestions on improving the program will be appreciated.
Edited by rekokich, 28 February 2020 - 11:58 PM.
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