Page 79 - BBC Sky at Night Beginners Guide to Astronomy - 2017 UK

WHAT TO SEE

LUNAR ATLASES

There are many atlases and wall charts vying to help you fi nd
the various craters, mountains and features of the Moon. They
have their strengths and weaknesses, and you’ll fi nd some easier
to use than others.
Watch out for any that fl ip the Moon so that south becomes
north, or make any other change to orientation. These are fi ne
for seasoned astronomers who use a specifi c telescope setup
to observe the Moon, but for those of us who switch between
correcting lenses, terrestrial telescopes, binoculars and the like,
go for a plain and simple map with north at the top. It’s also an
advantage to have one with high-quality pictures.
Wall charts are also good for getting a general idea of
where things are on the Moon. However, they’re less use at
the eyepiece unless they’re safely wrapped up in a dew-proof
coating, so it’s worth getting a laminated version.

LATIN

gradually changes as the Moon LINGO
spins on its axis, but even at this
slow rate you will be able to see
hour-by-hour movement. When you look at a map
That the Moon spins on its of the Moon, you’ll notice
axis may seem strange, as we that its physical features all
know the same side always faces have Latin names because
they were named a long
Earth. We are actually able to
time ago when Latin was
see 59 per cent of its surface as
more widely used. Here’s
the Moon ‘wobbles’ up and down
what those names mean in
and from left to right, an effect modern English.
known as libration.
Catena ..Chain of craters
We only see the one face
Dorsum ........Mare ridge
because a long time ago the
Dorsa..Group of mare ridges
molten material inside the Moon
Lacus ..................... Lake
caused it to become tidally locked Mare ......................Seas
to Earth. This ‘synchronous Mons .............. Mountain
rotation’ means that the Moon Montes ..Mountain range
spins once on its axis in exactly Oceanus .............Ocean
the same time it takes to orbit Palus ...................Marsh
Promontorium .....Cape
Earth. You can get an idea of
Rima ................... Fissure
how this works if you imagine
Rimae ...Group of fi ssures
yourself observing from the Sun.
Rupes .......... Escarpment
Over the course of a month you
Sinus ....................... Bay
would see the Moon spin once. Terra ...............Landmass
Of course, leaving Earth takes Terrae ............ Highlands
a bit of mastering, but once you Vallis ..................Valleys
can imagine it, understanding A lunar map will help you get to know the Moon’s features
the Universe becomes a breeze.
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