Calcolatore Magnitudine Limite
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Limiting Magnitude
13.5 mag
Limiting Magnitude vs Aperture
Formula
## Limiting Magnitude of a Telescope **m_lim ≈ 2 + 5 log10(D)** (D in mm) This empirical formula assumes a dark sky, normal magnification, and good optics. The naked eye (7 mm pupil) reaches about +6.0. Each doubling of aperture adds about 1.5 magnitudes (3.6× fainter stars).
Esempio Risolto
A 200 mm (8-inch) telescope.
- 01m_lim = 2 + 5 × log10(200)
- 02= 2 + 5 × 2.301 = 2 + 11.505 = 13.5
- 03Can see stars down to about magnitude 13.5.
- 04Gain over eye: 5 × log10(200/7) = 5 × 1.456 = 7.3 mag
Domande Frequenti
What affects limiting magnitude in practice?
Light pollution, sky transparency, magnification, observer experience, and telescope optics quality all affect the practical limit.
What magnitude are the faintest galaxies?
Many Messier galaxies are magnitude 8-10, easily visible in a 200 mm scope. The Hubble Ultra Deep Field reaches magnitude ~30.
Does magnification help?
Moderate magnification darkens the sky background, improving contrast for faint stars. But too much magnification dims the image. Optimal is about 1× per mm of aperture for faint objects.