Vacuum in the manifold drops as engine demand increases. If you use ported vacuum you always have a vacuum signal. If you want to make adjustments it can be done using the advance pot on the distributor when you use ported vacuum.
The decreasing or waning phases are when the moon shrinks from the full moon down to the new moon (darkness). As the moon wanes during the 3rd and 4th quarters, this is a good time to prune plants, as the water table is diminishing and so less sap will flow out of the cut ends.
The moon turns new on August 21, 2017 at 18:30 UTC. Some will call it a Black Moon, for a reason entirely unrelated to eclipses. More about that below. A moon at the new phase comes most nearly â for any particular month â to passing between the Earth and sun. This August, 2017 new moon makes that pass directly over the sunâs face, causing the much-anticipated August 21 total solar eclipse . On that day, the day of the coming new moon, the moon will pass between the sun and Earth. The moonâs shadow will fall on Earth.