while. the. craters. themselves. are. impact. scars. where.
meteors.miles.in.diameter.slammed.into.the.lunar.surface..
Most.of.these.features.are.billions.of.years.old.and.they.
remain. essentially. unchanged,. since. the. Moon. has. no.
atmosphere.to.weather.them.down.or.erase.them.
The.thin.lunar.crescent.sets.very.quickly,.but.just.a.few.
nights.later,.as.the.Moon.continues.on.its.path.around.
the.Earth,.it.will.be.much.higher.in.the.early.evening.sky.
and.remain.visible.for.several.hours..Now.you’ll.have.a.
chance.to.really.examine.our.amazing.neighboring.world.
at.your.leisure..The.crescent.will.be.much.wider,.and.the.
unlit.side.much.fainter.and.harder.to.see.than.before..
The.many.craters.visible.along.the.edge.of.the.shadow.
line.(known.as.the.“terminator”).will.really.“knock.your.
socks.off”!.Some.of.them.will.be.right.on.the.edge.of.the.
terminator.and.their.insides.still.filled.with.shadow..But.
in.just.a.matter.of.hours.the.Sun.will.rise.over.them.and.
the. shadows. will. disappear.. Other. craters. will. already.
be. further. out. into. the. sunlight. and. you’ll. be. able. to.
look. down. into. them. very. clearly.. Some. will. encroach.
into. others,. appearing,. as. indeed. they. were,. blasted.
onto.each.other..You’ll.definitely.want.to.use.the.15.mm.
(30X).eyepiece.–.and.more.powerful.ones.should.you.
have.any.–.to.bring.you.in.closer.and.see.all.the.rich.
detail. that’s. there.. (The. Edmund. 8. mm. Plossl. yields.
56X,.and.combined.with.the.2.5X.Barlow.lens.makes.it.
possible.to.reach.139X..See.the.“Accessories”.section..
But.also.read.again.the.discussion.on.the.useful.limits.
of.magnifying.power.that.appeared.earlier.in.this.guide.
under.“Optical.Specifications.”)
Phases.of.the.Moon
Figures on the inner circle show the Moon in its orbit; those on the outer
circle represent the Moon’s corresponding phases as seen from the Earth.
•
A, New Moon
(invisible)
•
B, Crescent
(waxing Moon)
•
C, First Quarter
(half Moon)
•
D, Gibbous
•
E, Full Moon
•
F, Gibbous
•
G, Last Quarter
(half Moon)
•
H, Crescent
(waning Moon)
A
Sun
C
B
Earth
H
G
F
E
D
Peering. inside. of. the. larger. craters,. you’ll. notice. that.
some.have.a.central.mountain.peak.within.their.raised.
rims.and.others.don’t..Many.of.the.bigger.craters.you.
see. are. about. 50. to. 80. miles. in. diameter,. and. 2. or. 3.
miles.deep..The.low-angle.lighting.along.the.terminator.
exaggerates. relief. and. makes. them. look. even. deeper.
than.they.really.are..Note.that.some.of.the.raised.rims.
have. steps. or. terraces. created. by. giant. landslides. as.
the.inside.walls.collapsed.after.the.initial.violence.of.the.
impact.ended..
As.the.Moon.grows.in.phase,.other.lunar.seas.become.
visible,. including. Mare. Tranquillitatis. where. we. first.
landed.on.the.Moon.in.1969..In.addition,.more.craters.
become. visible. in. increasing. numbers,. and. those.
formerly.so.obvious.become.difficult.to.find.as.the.Sun.
shines. high. over. them. and. their. shadows. disappear..
If.you.look.at.the.bright.highland.areas,.you’ll.see.that.
some.craters.are.surrounded.by.whitish.streaks..These.
lunar.rays.were.made.by.the.impact.throwing.material.
out.across.the.surface,.where.it.landed.in.long.streaks..
Long.rays.are.one.way.to.recognize.the.younger.craters.
on.the.moon’s.surface.
The. time. around. the. Half. Moon. or. First. Quarter. (so.
called.because.the.Moon.is.a.quarter.of.the.way.around.
Map of the Moon
fix
