• Astro-Physical Calculator - features pre-programmed physical constants and astronomical data.
• Constants and Equations for Space-Related Calculations
• Constants and Equations Pages, The - comprehensive internet reference for all things to do with astronomy, science and math.
• Fundamental Physical Constants
• Fundamental Physical Constants from the National Institute of Standards and Technology - values of the constants, related information, and searchable bibliography on the constants.
• Physical Constants and Astronomical Data

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