Telescopes & instruments · SNR = √N

Photon Shot-Noise SNR

The best signal-to-noise achievable when the only noise is the Poisson statistics of the photons themselves — the shot-noise limit. To double the signal-to-noise you must collect four times as many photons.

Source photons detected (e⁻)

Signal-to-noise ratio100

Formula: SNR = √N

Worked example

With the default inputs, photon shot-noise snr evaluates to 100 — 10,000 photons → SNR 100. The validator recomputes this against the known value on every build, so the formula is checked, not asserted.

Highlights

›Quadruple photons to double SNR

Limiting Magnitude

Knowledge connections

Associated withLimiting Magnitude

Sources

Facts on this topic will be cited from these primary and reference sources.

NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.

Loading…

Photon Shot-Noise SNR

Worked example

Highlights

The physics behind it

Knowledge connections

Sources

Photon Shot-Noise SNR

Worked example

Highlights

The physics behind it

Knowledge connections

Sources