v0.14 2020 Apr
====
* updated values to the **2018 CODATA** standard
* build script now produces a Raku module for Astro::Constants
* removed references to CGS in documentation
* added script that fetches constant values and uncertainties from NIST
* added warnings to module when using deprecated constants
* added a script to archive the current PhysicalConstants.xml file
* added dimensions to constants in terms of the SI base units
* values that are established by definition are assigned an relative uncertainty of 0
* clarified definition of critical density parameter, rho_c
* updated PhysicalConstants.xml schema definition
* changed name of **url** element to **source**
* added _authority_, _year_ and _reference_ attributes to **source**
v0.13 2018 May
====
* adding symbols to PhysicalConstants.xml definition file
* adding deprecation warning to Astro::Constants::CGS - to be removed from package v0.15
* alternateName element in PhysicalConstants.xml can now take a "type" attribute
* alternateName with type=deprecated are now listed with the deprecated tag, not the long tag
* adding RADIUS_JUPITER and MASS_JUPITER to the definition file
* adding notice of deprecation to Astro::Constants::CGS
* updating schema definition to accommodate symbol elements and allow attributes in alternateName
* switched ELECTRON_CHARGE to CHARGE_ELEMENTARY in long name and alternateName
v0.12 2017 Oct
=====
* Fixed MASS_HYDROGEN
* added warning for undefined constants in precision
* removed alternateNames from :long export tag
v0.11 2017 May
=====
* Fixed precision()
* Added the following constants for compatability with Astro::Cosmology
Added
-----
FOUR_PI - 4 * PI
STERADIAN - solid angle subtended by the radius squared in square degrees
Deprecated
----------
HUBBLE_TIME - should move to Astro::Cosmology as it's not really constant
v0.10 2016 Feb
=====
A couple of interface-breaking changes:
* 'list_constants' and 'describe_constant' have been removed and
people are directed to the docs, 'perldoc Astro::Constants'
* 'precision' is broken at the moment and will be fixed in the next version
These changes are enhancements/improvements:
* Short name constants are now *actually* constant and cannot be assigned to
* Values are now stored in an XML file, PhysicalConstants.xml
* Values have been updated using NIST's CODATA 2014 and the IAU 2009/2012
System of Astronomical Constants
* Long names have an added alternate name to facilitate migrating from
adjective_noun to noun_adjective.
List of name changes
====================
New names have replaced the old names which are retained in the file using
the <alternateName> tag
old new
=== ===
LIGHT_SPEED SPEED_LIGHT
ELECTRON_CHARGE CHARGE_ELEMENTARY
A_RAD DENSITY_RADIATION
VACUUM_IMPEDANCE IMPEDANCE_VACUUM
HBAR H_BAR
ELECTRON_MASS MASS_ELECTRON
PROTON_MASS MASS_PROTON
NEUTRON_MASS MASS_NEUTRON
HYDROGEN_MASS MASS_HYDROGEN
SOLAR_MASS MASS_SOLAR
SOLAR_RADIUS RADIUS_SOLAR
SOLAR_LUMINOSITY LUMINOSITY_SOLAR
EARTH_MASS MASS_EARTH
EARTH_RADIUS RADIUS_EARTH
RHO_C DENSITY_CRITICAL_RHOc
EARTH_MASS MASS_EARTH
EARTH_RADIUS RADIUS_EARTH
THOMSON_XSECTION THOMSON_CROSS_SECTION
ELECTRON_RADIUS RADIUS_ELECTRON
BOHR_RADIUS RADIUS_BOHR
SOLAR_TEMPERATURE TEMPERATURE_SOLAR_SURFACE
CMB_TEMPERATURE TEMPERATURE_CMB
SOLAR_DENSITY DENSITY_SOLAR
EARTH_DENSITY DENSITY_EARTH
SOLAR_GRAVITY GRAVITY_SOLAR
EARTH_GRAVITY GRAVITY_EARTH
SOLAR_V_MAG MAGNITUDE_SOLAR_V
SOLAR_V_ABS_MAG MAGNITUDE_SOLAR_V_ABSOLUTE
LUNAR_RADIUS RADIUS_LUNAR
LUNAR_MASS MASS_LUNAR
LUNAR_SM_AXIS AXIS_SM_LUNAR
LUNAR_ECCENTRICITY ECCENTRICITY_LUNAR
These 2 have had new names added, but I'm not sure which I like more
PERMITIV_FREE_SPACE PERMITIVITY_0
PERMEABL_FREE_SPACE PERMEABILITY_0
add in new definitions to <category>conversion
YEAR_TROPICAL 365.242 190
YEAR_SIDEREAL 365.256 363
YEAR_ANOMALISTIC 365.259 635
YEAR_ECLIPSE 346.620 073
Candidates for removal
======================
HUBBLE_TIME - this constant is inherited from Jeremy Bailin's Astroconst.
It is the inverse of the Hubble constant, valued at 100 km/s/Mpc and
is not constant. Suggest moving it into Astro::Cosmology
Introduced
==========
MASS_ALPHA - mass of the alpha particle