Moon Phase Illumination
Calculator
Illuminated fraction
0.5
Results
- Illuminated fraction
- 0.5
- Illuminated percentage (%)
- 50
- Phase index (0=new, 1=full)
- 0.5
Astronomy results
| Illuminated fraction | 0.5 |
| Illuminated percentage (%) | 50 |
| Phase index (0=new, 1=full) | 0.5 |
formula-map diagram
- Illuminated fraction
- 0.5
- Illuminated percentage (%)
- 50
- Phase index (0=new, 1=full)
- 0.5
Astronomical relationship
Formula
k = (1 + cos θ) / 2= 0.5
Note
This result is a simplified model: it applies the displayed textbook formula to the values you entered, assuming ideal spherical bodies, circular orbits, blackbody radiation and perfect optics, and ignoring atmospheric seeing, relativistic corrections beyond those stated, cosmological models and measurement uncertainty. Use published ephemerides and catalogue data for real observations.