Is it possible to observe a lunar eclipse during daylight? Normally
not. During an eclipse the sun and the moon are pretty much exactly opposite.
So if one is above the horizon, the other must be below the horizon. So
both can not be visible at the same time. One could say the body of the
earth blocks the view.
Only under very special circumstances can both object be visible when they are opposite to each other. At this time for example both touch the horizon at the same time. One rises when the other sets. Then comes our atmosphere. Refraction apparently lifts objects a bit higher. The more the closer the object is to the horizon. At the time of sunset the solar disk is lifted about 30arc minutes (about it's own diameter). Also if one observes from a very high mountain the apparent horizon is somewhat lower as we observe a bit around the curvature of the earth.
These conditions came together on August 16 1989 when a lunar eclipse happened where the moon passes through the shadow cast into space by the earth. During the partial phase of the eclipse the moon was rising as seen from the top of Mauna Kea on the island of Hawaii. The mountain has an altitude of 4200m and give the impression of rather standing on the edge of the earth than on the surface.
The following images show the setting sun and the rising partially eclipsed
moon. On the image showing the moon the sun light on the cloud tops can
be seen. Also very impressive is the shadow of the mountain acting as a
pointer to show the opposite direction of the setting sun.
