first radiation constant for spectral radiance

Document v1 · published by Koskamo · updated 2026-10-03

first radiation constant for spectral radiance = 1.191 042 972… × 10⁻¹⁶ W m² sr⁻¹ (CODATA 2022 recommended value, NIST)

Value: 1.191042972e-16 (NIST lists only these digits; the exact value continues)
Uncertainty: none; the value is exact by definition of the SI
Unit: W m^2 sr^-1

Source and provenance

Original source: physics.nist.gov
Published on Koskamo by: Koskamo
Citation version: Document v1
Reuse: CODATA 2022 recommended values from NIST, a work of the US government (public domain in the United States)

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Version history

Published by Koskamo2026-10-03
Version 1