Product
Glossary
Terms used in LightCurve.
| Term | Definition |
|---|---|
| A·σ | Albedo × cross-section of the diffuse sphere that would be as bright: an “optical size” (m²) |
| AEM | CCSDS Attitude Ephemeris Message |
| Airmass (X) | Thickness of atmosphere crossed, relative to the zenith |
| Albedo | Diffuse (Lambertian) reflectance |
| BRDF | Bidirectional reflectance distribution function, in sr⁻¹ |
| Characteristic magnitude | Mean brightness at the zenith at the end of astronomical twilight (Mallama) |
| DISCOS | ESA’s Database and Information System Characterising Objects in Space |
| Earthshine | Sunlight reflected by the Earth onto the satellite |
| Extinction coefficient (k) | Loss of brightness per airmass, mag |
| F₀ | Specular reflectance at normal incidence |
| GGX | Microfacet distribution of the specular reflection |
| LVLH | Local vertical, local horizontal frame |
| mag/arcsec² (mpsas) | Surface brightness of the sky: the larger, the darker |
| OEM | CCSDS Orbit Ephemeris Message |
| Phase angle | Angle at the satellite between the Sun and the observer; signed in LightCurve |
| Quicksat magnitude | McCants’ intrinsic magnitude: 1,000 km, full phase, brightest likely |
| SGP4 | Analytical propagator of TLE element sets |
| SNR | Signal-to-noise ratio; 5 is the detection limit |
| TDM | CCSDS Tracking Data Message |
| TLE | Two-line element set |
| Umbra, penumbra | Full and partial shadow of the Earth |