I am looking for the information on the percentage illumination of the moon during the different stages of a total lunar eclipse. Is there a database from where I can acquire information of lunar illumination, distance and angle for the July 27th 2018 lunar eclipse for a given location?
I found some chart regarding this, which is here:
The light level drops from about 50-60% prenumbral phase. It becomes noticeable.
If you want to get the percentage illumination of the Moon during the eclipse, install the Cartes du Ciel and turn on the Earth's shadow. Then you will be able to gauge the percentage value.