Transparency

Transparency graded on a 7 point scale and has been adapted for use in the Southern hemisphere. 

Score	Descriptor	Description	Visual test
0	Completely clouded out	possible light precipitation	no stars visible
1	Very Poor	cloud covering most of sky	momentary patches of clear sky
2	Poor	patchy cloud or heavy haze	alpha and / or beta Crux visible
3	Some what clear	Cirrus or Moderate haze	α, β, γ Crux visible
4	Partly clear	slight haze	α, β, γ, δ Crux visible
5	Clear	no clouds	Milky way visible by averted vision, α, β, γ, δ, ε crux visible
6	Very Clear	no clouds little sky glow, very little light pollution	Milky way visible, all stars of Crux visible plus coal sack
7	Extremely Clear	no clouds, minimal sky glow, Dark skies	ω Centauri and 47 Tucanae visible to naked eye

Seeing

Antoniadi Scale (seeing)