As. your. head. moves. a. bit,. the. image. will. sometimes.
disappear.partly.or.entirely..Don’t.be.concerned.about.
it.–.simply.re-center.your.eye..Make.sure.your.body.is.
positioned. so. that. you’re. relaxed. and. not. cramped. or.
getting.a.stiff.neck..
Keeping.both.eyes.open.is.the.key.to.avoiding.eyestrain..
With.a.bit.of.practice.you’ll.learn.to.ignore.the.extra.image.
seen.by.the.unaided.eye..If.it.doesn’t.feel.natural.to.look.
with.one.eye,.then.try.the.other..If.you.still.feel.you.can’t.
learn.to.ignore.the.other.image,.try.closing.the.other.eye.
gently.so.you’re.not.squinting,.which.causes.eyestrain..
Some.observers.prefer.to.use.an.eyepatch.(available.at.
most.drugstores).over.the.other.opened.eye..
On.bright.sunny.days.you.may.notice.a.fuzzy.spot.that.
seems. to. move. about. the. eyepiece. field;. this. is. the.
shadow.of.the.small.diagonal.mirror.and.will.completely.
disappear.under.dim-light.conditions.as.the.pupil.of.your.
eye.opens.much.wider.at.night..
If.you.wear.eyeglasses.for.either.near-.or.farsightedness,.
take. them. off. while. observing,. simply. correcting. your.
vision. by. focusing. the. telescope. as. described. below..
This.will.be.much.more.comfortable.and.let.you.get.closer.
to.the.eyepiece.when.necessary.to.see.the.full.field.of.
view.. Unfortunately,. those. having. severe. astigmatism.
should.keep.their.eyeglasses.on.while.observing.since.
refocusing.won’t.correct.for.this.aberration..
Focusing the Astroscan
The. image. is. focused. by. turning. the. focusing. knobs.
located. beside. the. eyepiece.. With. the. Astroscan,. the.
image. will. seem. to. almost. “snap”. into. sharpness.. For.
focusing.on.nearby.objects.you’ll.find.that.the.eyepiece.
comes.much.farther.out.than.it.does.for.distant.objects..
The. closest. focusing. distance. is. set. by. how. far. the.
eyepiece. tube. can. be. safely. moved. without. it. coming.
out.of.the.focuser,.but.generally.you.can.focus.to.within.
20.feet.or.so.for.close-up.nature.studies..
Focusing the eyepiece.
There’s.actually.no.such.thing.as.“exact”.focusing.of.
a. telescope.. What. happens. is. that. the. image. forms.
at.a.very.precise.and.exact.image.plane,.but.you.can.
see.the.image.well.at.various.settings.of.the.eyepiece.
because. the. eye. can. adjust. for. either. long. or. short.
focus.. The. best. general. practice. is. to. focus. “long.”.
This. is. done. by. extending. the. eyepiece. a. little. more.
than. necessary. and. then. focusing. in. just. enough. to.
get.a.sharp.picture..The.“long”.focus.causes.your.eye.
to. focus. as. for. a. distant. object,. its. most. comfortable.
position.. If. you. focus. to. the. maximum. “in”. position.
which.retains.a.sharp.image,.the.eye.accommodates.
for.a.close.object.but.finds.this.somewhat.more.tiring..
In.actual.practice,.you.should.alternate.between.long.
and.short.focus.since.frequent.changes.will.allow.you.
to.see.clearly.with.the.least.eye.fatigue.
Supporting the Astroscan
The.very.best.way.to.use.your.Astroscan.is.on.its.built-in.
base..This.sturdy.support.allows.the.telescope.to.swivel.
quickly.around.the.entire.sky.in.seconds,.and.it.doesn’t.
need.any.adjustments,.clamping.gadgets.or.other.such.
complications..You.can.put.the.base.down.on.just.about.
any.fairly.level.sturdy.surface.such.as.a.picnic.or.coffee.
table,.always.using.the.rubber.base.mat.to.protect.the.
surface..You.can.also.place.the.base.on.the.front.hood.
or. trunk. of. a. car.. (Note,. however,. if. the. car. is. warm.
–. especially. the. area. over. the. engine. –. it. will. produce.
Astroscan with
shoulder strap.
Astroscan on
its base.
