STEPHEN
Welcome to Idaho Skies for
the weekend of January 31st. We’re your hosts, Stephen…
DAN
…and Dan.
STEPHEN
The moon is at the perfect phase
this weekend. That’s the first quarter moon, or when Earth can only see half of
the illuminated moon. Remember, that
half of the moon is always experience day. However, this weekend, half of the
illuminated side is located on the far side and thus we cannot see it.
DAN
What makes the first quarter moon
so perfect for observing is that the shadows cast by the rising sun appear
stretched out to their maximum extent. And those shadows are visible along the
lunar terminator.
I’ll be back
DAN
No, not that kind of terminator.
Astronomically speaking, the terminator is the boundary between day and night.
And when it’s turned face on to Earth, shadows appear at their greatest angular
extent.
STEPHEN
Scan this area with your
binoculars or small telescope this weekend. You’ll see mostly craters in the
moon’s Southern Hemisphere and lunar seas in the north. Those lunar seas are
ringed with mountains where the lunar crust was thrown back by massive impacts
billions of years ago.
DAN
There’s an extra treat on Sunday.
That night the moon will be flanked by two star clusters, the Pleiades and the
Hyades. The Pleiades is the smaller of the two and it’s a wonderful target for
binoculars. The star cluster is 444 light years away. So the Pleiades that you
see tonight is what it looked like in 1576.
STEPHEN
That’s Idaho Skies
for the weekend of January 31st.
DAN
Be sure to read our blog for additional information.
It’s at idahoskies.blogspot.com
For Idaho Skies this is Dan…
STEPHEN
…and Stephen.
DAN
Dark skies and bright stars.
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