Astroimaging
While.your.Astroscan.was.not.specifically.designed.for.
imaging.the.sky,.being.essentially.an.instrument.for.visual.
use,.it.nevertheless.can.be.used.for.what.was.known.in.
the.past.as.“astrophotography,”.or.taking.pictures.using.
conventional.film..Today,.most.amateur.and.professional.
astronomers.have.abandoned.photographic.emulsions.
for. some. form. of. electronic. imaging. using. widely.
available.digital.cameras,.or.ones.especially.designed.
for.celestial.imaging.known.as.CCD.(or.charged.coupled.
device).cameras..These.have.a.much.higher.“quantum.
efficiency”. than. film. does,. making. it. possible. to. take.
pictures. of. faint. objects. in. just. minutes. that. used. to.
take. hours!. Both. conventional. astrophotography. and.
electronic.astroimaging.are.very.involved.subjects,.and.
many.books.have.been.entirely.devoted.to.the.techniques.
of.shooting.both.celestial.and.terrestrial.targets.
Your. new. telescope. is. actually. an. excellent. telephoto.
lens..The.same.qualities.which.make.it.a.fine.astronomical.
instrument.also.serve.when.used.as.a.lens.in.front.of.a.
35.mm.single.lens.reflex.(SLR).camera.(either.digital.or.
film)..Its.large.light-gathering.power.provides.telephoto.
capabilities.under.adverse.lighting.conditions.which.may.
preclude. photography. with. slower. lens-type. telephoto.
systems.. When. used. in. this. manner,. the. lens. of. the.
SLR. camera. is. removed. (the.Astroscan. becoming. its.
lens!).and.replaced.with.a.“T.Compatible.Adapter”.which.
is. specifically. made. for. your. particular. camera. model..
Adapters.for.most.popular.SLR.cameras.are.available.
from. Edmund. Scientific.. This. method. of. photography.
is. called. “eyepiece. projection,”. in. which. the. image. is.
photographed.directly.through.the.eyepiece.with.the.aid.
of.Edmund’s.Variable.Sliding.Tube.Camera.Adapter.(see.
the.“Accessories”.section)..This.device.allows.the.user.to.
vary.the.eyepiece.magnification.without.using.extension.
tubes.or.removing.the.adapters.from.the.focusing.tube..
Again,.as.mentioned.above,.a.“T”.adapter.is.required.to.
mount.the.camera.to.the.telescope..
It’s.important.that.the.Astroscan.and.its.base.are.seated.
on. a. sturdy. support. like. a. picnic. table. or. the. Edmund.
Scientifics.Telescope.tripod.(see.“Accessories”.section).
for. any. type. of. astroimaging.. The. old. rule. in. film.
astrophotography.was.to.take.lots.of.pictures.at.different.
exposures.to.hopefully.get.one.that’s.perfect.for.the.object.
you’re.shooting..However,.one.of.the.beauties.of.digital.
imaging.is.that.you.can.see.the.result.of.your.exposure.
immediately.and.adjust.it.accordingly.to.correct.for.under-.
or.overexposure..Focusing.in.either.case.is.done.with.the.
Variable Sliding
Tube Camera
Adapter
(#30429-10)
telescope.until.you.see.a.sharp.image.on.the.camera’s.
viewing. screen.. It’s. probably. best. to. experiment. with.
photographing.objects.in.the.daytime.to.get.a.feel.for.the.
process.. Exposure. times. may. range. from. as. short. as.
1/1000th.of.a.second.to.1/60th.of.a.second,.depending.
on.the.ASA.rating.of.the.film.and.how.bright.the.day.and.
subject.are..
Exposures.at.night.will.be.correspondingly.longer.since.
celestial.objects.are.much.fainter.than.daytime.ones..The.
Moon.is.definitely.the.best.target.to.begin.with,.exposure.
times. being. determined. by. the. Moon's. phase,. among.
other.factors..Note.that.even.with.eyepiece.projection,.
the. image. of. the. Moon. will. be. relatively. small. and.
those. of. the. planets. even. smaller.. Using. the. Edmund.
Barlow.Lens.(see.“Accessories”.section).in.conjunction.
with. an. eyepiece. significantly. increases. the. effective.
magnification.and.resulting.image.scale..However,.the.
combination.of.Barlow,.camera,.and.sliding.tube.adapter.
tends.to.make.the.Astroscan.top-heavy.and.the.scope.
may.not.stay.on.your.target,.depending.on.the.angle.at.
which.the.telescope.is.pointed..
Sky.shooting.with.your.Astroscan.is.necessarily.limited.
to.short.exposures.of.no.more.than.a.minute.or.two.due.
to.the.rotation.of.the.Earth,.causing.the.images.to.trail..
But. that’s. still. long. enough. to. get. pictures. not. only. of.
stars,.but.also.of.the.brighter.deep-sky.objects.like.the.
Pleiades.Cluster,.the.Orion.Nebula.and.the.Andromeda.
Galaxy. using. a. digital. camera.. Both.
Sky & Telescope
.
and.
Astronomy
.magazines.frequently.carry.articles.on.
astroimaging.–.and.also.accept.pictures.taken.by.readers.
for. publication!. For. those. desiring. to. try. their. hand. at.
conventional. film. photography,. the. Edmund. booklet.
Photography with Your Telescope
.contains.much.helpful.
information.on.both.celestial.and.terrestrial.shooting.with.
your.telescope,.and.discusses.other.techniques.such.as.
prime-focus.imaging..
