and
are the apparent major and minor axis of the
planet (
being the planet radius and
the geocentric
distance in km).
is the cosmic background radiation (2.7 K)
We list in Table 1 the brightness models used in the original ASTRO implementation (Legacy models), the models we propose to implement (2024), and the models used in CASA.
| Planet | ASTRO Legacy | ASTRO 2024 | CASA | |||
| Mercury | Flat Spectrum | Flat Spectrum | No model | |||
| (too close to the Sun) | ||||||
| Venus | Spectral Index | Spectral Index | Physical model | |||
| Clancy et al. 2012 | ||||||
| Mars | Flat spectrum, |
Physical model | Physical model | |||
| Lellouch et al. | Butler et al. | |||||
| Juptier | Flat spectrum | Physical model | Physical model | |||
| ESA2 (R. Moreno) | ESA4 (G. Orton and R. Moreno) | |||||
| Saturn | Flat spectrum | Physical model | No model | |||
| ESA2 (R. Moreno) | ||||||
| Uranus | Spectral index | Physical model | Physical model | |||
| ESA2 (R. Moreno) | ESA4 (G. Orton and R. Moreno) | |||||
| Neptune | Spectral index | Physical model | Physical model | |||
| ESA5 (R. Moreno) | ESA3 (G. Orton and R. Moreno) |