We
had a very good view of Kies Pi, a lunar volcanic dome last night at
250X. These subtle volcanic features are only seen at times of low
illumination. They are almost always found on the margins of the Mare.
You can even see a summit pit on several ones if you have good optics
and seeing conditions.
A
lunar dome is a low viscosity surface volcanic feature. They have
gentle slopes much like certain Icelandic volcanoes. Called shield
volcanoes, the lava flows easily due to the chemical make up and forms
wide low features generically known as volcanic domes. These exist both
on Earth, where they are more common, and on the moon where they are far
more rare.
There
was a time in the 1940's though 60's and earlier that many thought
lunar craters were volcanic features (even though no such volcanic
feature was ever found on earth). Sometimes called crypto volcanic,
which was scientific terminology for something you can't see (and may
not exist outside of the imagination of the observer), the term had also
been applied to meteor crater in Arizona during the early 20th century.
There too, in that terrestrial case, no other volcanic feature was
known to exist but hey it must be volcanic so let's call it "crypto." In
both cases, earth bound meteor crater and lunar craters, the volcanic
description was imaginary. But there are real volcanic features such as
Kies Pi on the moon though they not nearly as prevalent as once thought.
These are fun objects to observe due to the subtle nature and low
relief. You have to get the lighting just right in many cases to be able
to see them. There exists about a dozen of the these lunar objects that
make for challenging observations. It
is located to the left of the distinctive crater Kies. Kies is close to
Copernicus so navigation is not too hard.