Telescopes & instruments · m_lim ≈ 2.7 + 5 log₁₀(D_mm)

Limiting Magnitude

A rule-of-thumb estimate of the faintest star an aperture can show under dark skies. Approximate — real limits depend on sky brightness, magnification, and the observer — so it is offered as a guide, not a guarantee.

Aperture (mm)

Limiting magnitude12.7mag

Formula: m_lim ≈ 2.7 + 5 log₁₀(D_mm)

Worked example

With the default inputs, limiting magnitude evaluates to 12.7 mag — 100 mm → ~12.7 mag. The validator recomputes this against the known value on every build, so the formula is checked, not asserted.

Highlights

›100 mm: ~12.7 mag (approx.)

Angular Resolution (Rayleigh)

Knowledge connections

Associated withAngular Resolution (Rayleigh)
Associated withPhoton Shot-Noise SNR

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.

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Limiting Magnitude

Worked example

Highlights

The physics behind it

Knowledge connections

Sources

Limiting Magnitude

Worked example

Highlights

The physics behind it

Knowledge connections

Sources