Magnitude Converter
Convert between apparent and absolute magnitudes, calculate distance modulus, and determine luminosity ratios. Essential for stellar photometry and astronomical distance calculations.
Magnitude Conversion
Extinction (Optional)
Understanding Stellar Magnitudes
Apparent vs Absolute Magnitude
Apparent magnitude (m) is how bright a star appears from Earth. Absolute magnitude (M) is how bright the star would appear if it were at a standard distance of 10 parsecs.
Distance Modulus Formula
The fundamental relationship between apparent magnitude, absolute magnitude, and distance:
m - M = 5 × log₁₀(d) - 5
Where:
- m = apparent magnitude
- M = absolute magnitude
- d = distance in parsecs
Magnitude Scale Properties
- Lower numbers = brighter objects
- Each magnitude difference = 2.512× brightness change
- 5 magnitude difference = 100× brightness change
- Negative magnitudes are very bright (Sun: -26.7, Sirius: -1.46)
Example Stellar Magnitudes
| Object | Apparent Magnitude | Absolute Magnitude | Distance |
|---|---|---|---|
| Sun | -26.7 | +4.83 | 1 AU |
| Sirius | -1.46 | +1.42 | 8.6 ly |
| Vega | +0.03 | +0.58 | 25 ly |
| Polaris | +1.98 | -3.64 | 433 ly |
| Betelgeuse | +0.50 | -5.85 | 700 ly |