The scale below has been reversed from the Webb Society scale which puts excellent values at 1 and poor values at 5 in order to match Meteoblue. However the exact decriptions may not tally exactly with the Meteoblue astronomers’ forecast. To be monitored.

Seeing

1. Very bad seeing, hardly stable enough to allow a rough sketch to be made.
2. Poor seeing, constant troublesome undulations of the image.
3. Moderate seeing with larger air tremors that blur the image.
4. Slight quivering of the image with moments of calm lasting several seconds.
5. Perfect seeing, without a quiver.

Transparency

1. Poor to terrible. Very hazy, bloated stars, haloes around bright stars, Moon and planets or there’s a lot of cloud. Not worth going out.
2. Milky skies, moderately hazy bit observing of brighter NGCs doable/drifting cloud.
3. Clear, some haze visble. Milky Way still visible but not detailed.
4. Very clear. Milky Way bright but not iridescent. No clouds. M31 visible.
5. Very clear and transparent. Milky Way ‘iridescent’. M33/M81 visible.