Takahashi CCA-250 User manual

⊂
orrected⊂assegrain AstrograPh
G
‐
INSTRUCT10N MANUAL
■
■
KAHASHl

丁hank you very:η uch for your purchase ofthe TAKAHASHI CCA‑250 Cor‐
rected Cassegrain Astrograph.丁he CCA‐ 250 is an original design by ttakahashi
that uses parabolic primary rnirroら a spherical secondary′ and a 3‐ element
correctontthere are also the optionalreducers and extender producing great
刊exibility for imaging.ln orderto enioy the cCA‐ 250 to the limits of ls capa‐
bility′ read this rnanual very carefuHy and falTliliarize yourself v th a‖ the func‐
tions of this astrographB A‖ the instruments have been carefuHy coHimated
and inspebted before shipment.lfthere is any damage′ contact your local
dealer iΠ llTlediately。
O vvhen you atthch the tube assembly onto a rnount′ do it very carefu‖ y so as not
to drop it.lt could cause iniury.
●
Do notlay the tube assembly on any surface thatis not completely level and
sufficiently large to hold the CCA‑250.An uneven surface could cause the in―
strument to fa‖ off on to the ground.
●
Do not place the tube assembly in the sunny place.丁 he direct sunlight wi‖ heat
up the interior 6fthe telescope and could cause damage.
●Keep small children away from small obiectS llke oculars to preventthem from
accidenta‖ y swa‖ ovving a part.
●
Keep the shipping carton in a safe place away frorn any flame because it con―
tains flamrnable rnaterials.
UNDER NO CIRCUMSTANCES WHATSOEVER
SHOULD THE CCA‐ 250 BE POINTED AT THE SUNロ
DIRECT VIEWING OF THE SOLAR IMAGE WILL
CAUS■ INSTANT BLINDNESS.
∠ゝ
DANGER
‑2‑

Table of Contents
Waming&Caution… …… …
…
…
…………
・
・
2
Table of Contents ―
口
・
……
口
・
口
・・・
……
…
…
・・
…
…
…
・・
3
Specifications ・
…
・
・
¨
……
……
・
・
……
口
・・

・
・
…
・・
…
……
・
4
Accessorles ・・・
・
…
口
・・・
・・・・
……
…
…
………
・・
……
…
・・
¨
・
5
Tubeノヘ SSembly Layout ・・
……
…
Ⅲ
・・
・
¨¨
・・
…
・
6
0ptical systen∩ features ・
口
・・

0・ …………
…
・
口
・
7
1nstaHation ………
・
・
¨
……
…
ロロ
……
・・
…
口
・
………
・・
…
8‐ 14
Photo/visual application …………
・
・
‑0日 15‐ 18
Systern parts ‑3● 口
●
…
………
…
…
ロロ¨
…
…
・
0… …
19‐ 23
CoHimation .・ .・ …
…
…
・
ヨ
…
…
・
口
"・・・・・
口
・・
口
・
・
・
…
・
24‐ 28
Care&l aintenance.… …
…
・・
…
・
・
…
・・
……
・
29‐ 30
Systerrl Chart ………
・
口
……
……
……
¨
………
…
口
・
31‑33
‑3‑

SPECIFICAT10NS
Optical system Corrected Cassegrain astrograph
Effective aperture 250rrlrn
Effective focallength 1250mrn
圧
ffective focal ratio 5.0
1mage circle φ88mm dia.
Backfocus 180.81nrn
Metal Back l15.5mm
<With Reducer‐CR O.73X>
Effective focallength 910mm
Effective focal ratio 3.6
1mage circle φ38mm dia.
<With Extender‐ CR l.5X>
Effective focallength 1880mln
Effective focal ratio 7.5
1mage circle φ40mm
<With 645 Reducer‐CA O日72X>
Effective focallength 890rTlrn
Effective focal ratio 3.6
1mage circle φ60mm dia.
Outer diameter of main tube 306「lrn
Totallength oftube assy 870「 l rTl
Total weight oftube assy 22.8kg[50.7 1bsl inCluding 7x50 findeL
dovetail adapter
Finder7x50、〃
/apparent field of 4口 2° lrv/reticle i‖ unη inator
Accessories lnstruction rnanual′ 、〃
arranty&inspection
certificate′ dove―tail adapteL tools
‑4‑

ACCESSORIES
Corrected CassegrainAstrograPh
⊂CA‐己50
:NSTRU CT:ON MANUAL
TAKAHASH日
inspection certificate
:nspection certiflcate 7X50mm Finder&bracket
(not for u.s.market)
tools
instruct;on manual
dove― tail saddle
INote]
ln orderto use the auto‐ focus function′ an
ASCOM compliant software disc′ USB
cable′ AC adapterfor DC12V l.5A{polarity
center tt plus} ′
are required.
躙 嘲
□
E‐コ
ロ
‑5‑

Bridge
LAYOUT OF TUBE ASSEMBLY
Dew Sh:eld
Dew Shield Cover
Dew Sh:eld Cover Knob ttop Ring
Pttmary Mirror Collimation Screws
Finder Scope (3 in a set)
Bridge
Cooling Fan
BOttom Ring Dove― 丁ail
Main ttube(CarbOn F:ber)
Finder Scope
Dove― 丁all
Pmary Mirror Cell
Stud for Attaching Finder
Correcter Lens
Cell Cap
Focuser Drive Unit
Focuser Drive Unit
P mary Mirror Cell
BOttom Ring
Screw
Spider
Spider Ring
p Ring
Clamp一‐
判
8:[IIIIIEIIゴ III}←一一
一
―
Dove― 丁
ail Adapter
Secondary Mirror Bafne
Focuser Motor Un:t
Dove―丁ail
S
‑6‑
Dove―丁ai:Adapter
Bridge Spider Attusting
Secondary Col‖ maJon Screws(3 in a set)

OPTICAL FEATURES
CCA‐250 uses a parabolic prirTlary rnirror
and a spherical secondaryr Which are easier
to produce′ resuiting in an ideal optical sys‐
teln producing corrected images、 〃
ithout
astigrnatism.
丁his optical design is an original and is an
advance from the senli‐Ritchey Chretien de‐
sign lTlaking the curves ofthe primary and
secondary same radius so as to rnake the
total su「l of Petzval zeroo MoreoveL the 3‐
element corrector can make the field per‐
fectly flat surpassing the BRC design.
Optical perforinance atf/5′ the CCA‐250 can
produces a 50rnrn image circle、〃ith less
than 6‐ rrlicron image in the centeL able to
easily cover a mediun∩ forrnat and larger
CCD with a totalimage circle 88mm atf/5.
丁
his iarge image circle will also be able to
handle 67 size CCDs when they become
avallable in the rnarket.
丁
he FnOSt remarkable feature of the CCA‐
250 is its ability to be a tri‐ focus astro imag‐
ing platforrn using the dedicated reducers
and extender.丁 he CCメい250 can be used at
the native f/5′ f/3口 6 1rvith the Reducer‐ CR
O.73X and f/7.5 with the Extender‐ CR l.5X′
which have been developed for the
Takahashi′ s original Mewlon― CR optical
systems.Moreoveら in order to cover the
largerirnage circle of future CCDs′ a dedi―
cated 645 Reducer‐ CA which produces
60mrn circle with less than 10‑rnicron irn―
ageis now under development.
An ASCOM Compliant Auto Focus:ng Sys―
tem is standard.FocusMax and lⅥ axilTIDL
can be used、 Ⅳ:th this system to control criti‐
cal focusing口 An ASCOM compliant dr er
can be downloaded from the Takahashi
website.
Please access:
[htt p://WWwatakahashilapanecOm/
supporteohtml]
to download the ASCOM compliant driver
forthe Active Focus systelTl ofthe CCA‐ 250.
Cooling Systeln:
3 cooling fans are provided on the rrlirror
ceH cover ofthe tube assembly。 (Э n/off Op‐
eration forthese fans is contro‖ ed automati―
cally by ASCOM compliant software or
manua‖y口 ln orderto run these fans′ three
sensors are provided to rnonitor the teln‐
peratures ofthe primary mirroL the inside
and outside temperatures ofthe rnain tube.
‑7‑

instaHation
■I Attaching Finder Bracket
丁he finder bracket can be attached attwo
optional positions、 Ⅳith iⅥ 1 0x25[this a tube
holder bolti bolt.Be careful notto screw the
bolt only′ which could hitthe tube.
■I Attaching Finder Scope
Pu‖ the adiuSting screws of the finder
bracket to clear the space for the finder
scope、〃
hen setting.Remove the i‖ unlina‐
tor before setting the finder in the bracket.
丁
hen setthe finder scope with equal space
between the adiuslng screws and lock the
lnder scope with adius ng screws.
Again attach the i‖ unlinator in place.
■
Dove―Tail and Bridge
Do notremove the dove‐ tail or the bridge.
丁
hese parts are rrlade of alun nun∩ and the
main tube is made of carbon fibere So′ these
are assembled by a special method to off‐
set different expansion rates and contrac‐
tion ofthese various rrlaterials.Usua‖ y there
is no need to remove these parts′ but if reロ
moved′ return the resin vvashers to their
Finder Bracket
Fiber Washer
Ring
I‖ urninator
7x50 Finder Scope
A‖ en Wrench
Ａ ハ ■︱︱ ︱ ︱︱ ︲
ｍ
Botto
Allen Bolt(M10× 25mm)
Adusting Screw
Nut
Screw
‑8‑

original pos:tions.First′ loosen the sma‖
screvヴ a bit and loosen the lⅥ 6 A‖ en bolt.
When the plate:s removed′ the sma‖ resin
piece setin the screw hole、 〃ill come oute
Levelthe dove―tail so that the tube as―
sembly can be set easily on the lnount.
Turn the dove‐tall saddle plate clamping
screws counter‐ clocklrvise untiithe scope
is properly positioned.
Place the dove‐ tall attached to the tube
assembly firlTlly into the key‐ way ofthe
dove‐tail saddle plate.Make sure thatthe
tube assembly is firlnly locked into the
dove―tall saddle plate.Do not hold the
adapters on the rear ofthe scope、 Ⅳhen
lifting the tube assembly.Doing so could
damage to the adapters.
Allen W鰤 市
Dove― tail Adapter
Holder Base
Dove― tail Handle
2ロ
Allen Wtth
斜
:1月14daJ
Spring Washer一
Plate Bracket￢
3ロ
Plate Metal Allen Wrench
Bridge
1ヽ
丁op Ring Dove―丁all
Plate Metal Plate Metal
■
Placing the tube assembly onto the
Mount
To place the tube assembiy onto the rnount′
the dove tail saddle plate is used.丁 his al―
lowsthe tube assembly to be taken on and
offthe rnount vvithout tools′ and ifthe tube
assembly is not inserted into the saddle
plate correctly′ the(DTA could faH out′ pos‐
s:bly causing iniury to the user or damage
to the telescope.丁 he、″
eight ofthe tube as‐
semblyis about20kg{441bs).ltiS a good idea
for two to place the CCA‑250 on to the
saddle plate.
1.Attach the dove‐ tail saddle plate firrnly
ontothernountvvith4eaoM10x30Allen
bolts.
冒
冒
Dove― ta‖
‑9‑
Male Dove―ta‖ Adapter
Do∨e―tail Adapter

■I Balancing
丁he CCA‐250 is supplied with long dove tail
to help lrvith balancing a variety ofimaging
packages.ヽⅣ
hen the tube assembly is
placed on to the rnount′ balance itfrom front
to back using the dovetail′ and in R.A.by
shifting the counter weightse When balanc‐
ing′ attach the imaging package to the tube
assembly.
丁hen rebalance in the arc thatthe instrument
will cover as the:mage is rnade.
丁
his vvi‖ insure good tracking by the mount.
O Balancing in the Declination Axis
l.Loosen the Declination clamp and lockin
position when the scope is horizontal.lf
the scope is out of balance′ clamp the Dec
axis and balance the load in RA first.
2口 丁hen loosen the Declination clamp′ hold‐
ing on to the tube to keep itfronl svvingロ
ing away and striking the rnount′ ITlake the
OTA horizontalロ
3。 Holding the scope with on hand loosen
the saddle plate clamps slightly vvith the
other hand′ which a‖ ows the tube to be
moved back and forth.
4.lfthe instrumentis not balanced′ loosen
the Dove‐ tail handle and s!ide the tube as―
sembiy forward and backward untilitis
balanced.
●
Balancing the R.A.Axis
laVVhen balancing in the Declination is coFト
plete′ lock the Dec.clamp.
2.Loosen the R.A.clamp and see how ifthe
R.A.axis is balanced.
3.lf it is not balanced′ shift the counter‐
weight until balancing is complete.
4.Balancing may require an additional
counter weightis]ロ
■Camera and Balance
When the tube assembly is locked in the
position、Ⅳ
here it does not rnover you can
attach a 5kg camera to the camera angle
adiuSter On the rear ofthe OTA so long as
the scope and camera are balanced in Dec..
Dove― tail Stop Bolt Loose Dove―tail Handle a bit
‑10‑
Dove― ta‖ Stop Boit

■I Attaching Adapters
Before shipment′ the adapters have been
attached for visual use as illustrated.ln place
of an oculaL an adapter cap is attached.
M98Xl.0
38.5mm
Aux.Ring Aux.R:ng Coupling(丁 W)
Camera An」 e Aduster
(CAA)
■
Attaching Other Accessories
Various imaging adapters can be attachedロ
Please study the systern chart so that the
parts、〃:￨l be attached correctly. lncorrect
attachment vvi‖ not a‖ ow maxilnurTl perfor‐
mance and lrvill not focus correctly and it
wi‖ reduce the perforrnance ofthe scopeロ
■Camera Angle Adiuster(cAA)
丁he CAA is attached to the tube to a‖ ow the
irnaging package to be rotated 360° . Loosen
thelock screw and then turn the CAA to any
desired position.When the CAA is used′
rotate the entire camera to keep the T― ring
from conling loose.Check the focus after
the camera is turned.
M98Xl.0 M98Xl.O M98 Xl.O M54 XO。 75 M43XO。75 M36.5Xl.O φ31.7mm
Visual Adapter 。
cul!lrAdapter °Cular
(31.7mm)(11/4″ )
︱上 Ｖ６
Coupling
Lo hten
CAA
‑11‑

■I Focuslng
ln order to irnage any oblect sharply after
the imaging package is attached′ best pos‐
sible focus:s necessary.ln orderto use the
CCA‐ 250 to its maximum capabil:ties′ pre―
cise focusing is necessaryo tthe CCA‐ 250
uses a computer controHed focusing sys‐
tem that rnoves the secondary ITlirror using
a pulse rnoton tthis systenl can also be op‐
erated manuaHy.
■
How to:η anuaHy operate the
focusing system
A center positive DC 12V l.5A AC adapter
is used forthe power source.lnsertthe plug
into the power receptacle ofthe drive unit.
An on/off SWitch is not provided so switch‐
ing is rnade by inserting and pu‖ ing outthe
plug.ヽ Vhen the poweris on′ the motor set
on the secondary lTlirror starts to detectthe
original position.At first′ it rnoves the sec―
ondary mirrorto the primary nlirror side and
stOps onceo Then′ it rnoves the secondary
mirror near the focal point and stops itself.
Ⅵ
′
hen FOCUS+{plus}iS preSSed′ the dis―
tance bet、〃
een the primary and the second‐
ary is Ⅵ
パdened and the focal plane willrnove
inward.い′
hen FOCUS‐ {lminuS)iS pressed′
FOCUS+Switch(black):
Widens the distance between
the primary and the Secondary
FOCUS― Switch(red):
Narrows the distance between
the primary and the Secondary
the distance between the primary and the
secondary is narrowed and the focal plane
wi‖ move out、〃
ard.Each FOCUS button
ramps up the rnotor when itis pressed and
gradua‖ y speeds up the rnotor when itis
continously pressedeWhen these buttons
are pressed together for 6 seconds′ the
motor vviH detectthe original positione When
the focus button lN{red}iS pressed′ the sec‐
ondary is shifted toward the opening ofthe
tube and the focal plane、 〃ill rnove inward.
い
′
hen the focus button OU丁 {white)iS
pressed′ the secondaryis rnoved toward the
primary and the focal plane will rnove out‐
ward.
■
Fan Operation
When focusing inanua‖y′ the on/off fan
switch operates the cooling fansロ
When the button is pressed the cool:ng fans
turn on and when the same button is
pressed again the cooling fans turn off。
⊂⊂
A‐己
50
TAKAHASHロ
Fan Switch(white)
‑12‑

■I Finder Alignment
ln the view field of a telescope′ the rnagnifi‐
cation is very high and the view field is nar‐
row so itis very hard to center a desired
ObieCto When a camera is attached forim―
aging′ the view field:s so dark and hard to
see the obieCt.丁 herefore′ it is very diff:cult
to make certain r the ObieCtiS centered in
the field。
A finderis a sma‖ telescope、 〃ith、〃ide ap‐
parent field and low magnification.So′ if it
is aligned、″ith the rna:n scope and a de‐
sired obiect iS Centered by it beforehand′
the obiectin the■ eld ofthe main scope is
also centered.Finder alignment procedures
are as fo‖ ows。
●Focusing
When an obieCt10Cated far away and k is
out of focus′ proceed the foHovving proce‐
dures.
1.Loosen the lock ringロ
2.Look forthe best focus′ turning the eye‐
piece clockwise and counter clock‐ vv:se′
viewing the obiect.
3.VVhen itis focused best′ tighten the lock
r!ng・ Finder Attusting Screw
Finder Reticle I‖ uminator
●
Finder Adiustment
l.Attach a loⅥ ノ
pOwer ocular to the visual
back and center a conspicuous( DbieCt 10由
cated far away. View
2.Change the eyepiece、Ⅳith high power one
and centerthe obieCt again.
3.lfthe obieCtiS Seen different as shown in
the illustration′ adiuStthe finder scope so
as to center the obiect wtth the following
manners.
4.Turn aH the lock nuts unt:lthey reach the
head ofthe alignment screws.
5。 ln orderto move the crosshairin the di―
rec on ofthe arrow′ 刊rstloosen screw{a)
and 
ghten{push)the nder wkh screw
(C).thiS procedure will move the crosshair
in the desired direction.丁 he top ofthe
finder vvi‖ rnove in the opposite direction
and the obieCt Will move in the direction
ofthe smaHer arrow.Referto the i‖ ustra―
tion.
Scope
皇 ず
Vlew Field of F:nder Scope
of Ma:n
Lock Screw Lock Ring
Finder Scope Eyepiece
Finder Bracket
View Field of Finder
Field of Main Scope
‑13‑

6.Similarlyr adiuSt the direction ofthe lnder
wヒh3sets of adiuSIng screws.
7.When the opticalaxes of both finder scope
and rnain scope are para‖ eled′ lock the
finder scope vvith the lock nuts.Learn the
relationship betⅣ een the lTlovement ofthe
three adius ng screws.rthe inder cannot
be rnoved in the desired direction′ loosen
the locking nuts.
丁hese procedures should be done in the
daytime to prepare your observation in the
night.Remember that the l■ otor drive
should be engaged when the finder is
aligned、″ith the main optics′ using a bright
star at night′ because staris rnoving at the
sidereal rate.
■
I Reticle l‖ unlinator
Takahashi 7x50 finder scope、 〃
ill
optional reticle i‖ unlinator.丁 his
the interrupted crosshair in the
accept the
i‖ uttlinates
finder and
makes the centettng obieCtSin the 
ewtteld
easier.丁 he i‖ urninator is inserted into the
hole covered by the slotted screw nextto
the eyepiece end ofthe finder scopea
lf you wish to turn the iHunlinator on′ turn
the chrome knob ciocklrvise.丁 he Knob、Ⅳill
click when itis turned on.丁 his、Ⅳill a‖ ow the
i‖ urninator to be changed to suit the sky
conditions.Turning the knob counter― clock"
wise willturn the iHunlinator off.丁 he knob
will click once again、 〃hen itis turned off.
■
I Replacing Batteries
ln case the battery rnust be replaced′ take
outthe case′ turning it counter‐ clockvrise as
i‖ ustrated.Before replacingthe batteries′
clean the surface ofthe batteries and place
them into the battery holdeL checking the
polarity.Use two silver ce‖ 1.5v batteries
S76 or equivalent.
cap and turn
as arrowed
A
チ ′ Ｂ
Hold the knurled
the battery case
Mercury Battery
(V76‑PK)
‑14‑

Observation
■
Cooling System
Before imaging the CCA‐ 250 rnust equalize
to the ambienttemperature ofthe lmaging
site.丁his process can be shortened with the
use ofthe cooling system which is part of
the rear ce‖ ′
丁he syste爾l uses three sensors
lrnirrOL inside tube and outside tubel and
three low vibration motors、 Ⅳhich can be
used manually orin coniuncJOn wtth focus‐
ing software to bring the instrument to
ambient temperature.
■Astro!maging atthe Prime Focus
丁hisis the ilnaging method placing the CCD
atthe prime focus plane ofthe CCA‐ 250.丁 he
focal!ength of a telescope at prime focusis
1250 1rvhich needs a high quality autoguider
to keep the steHarirnages perfectly focused.
A CCD calmera or35mn∩ DSLR can be used
to rnake images.
■I Back Focus
丁he back focus of this instrument is
155.4爾lln from the CAA and 193.9 from the
rear of the lnirror ceH.lt is:mportant that
the CCD chip to be placed precisely atthe
focal planeB tth:s willinsure the best pos―
sible image.
Aux.Ring cOupling(丁W)
Camera An」 e Aauster Aux.Ring
(CAA)
‑15‑

■I Focusing
丁he CCA‐250 uses an ASCOM compliant
Activ Focus focusing systen∩ that can be
controHed with popularfocusing sottare.
丁
his softvvare aHows the CCA‐ 250 to use
computer controlled focusing.An ASCOM
download is available on the Takahashi Ja―
pan website as we‖ a Takahshi America
webske.When an obiectiS Setto beimaged′
connect your PC vvith your CCA‐ 250 and
focus by using an ASCOM compliant soft‐
ware focusing sottare available.Forfurther
details′ refer to the instruction lTlanual at‐
tached with the software thatis used.
Power Source
丁oa PC
‑16‑

■Filters
Some of accessories for CCA‐ 250 can ac‐
cept 48「lrn′ 58Flln′ and 82Flrn filten When
necessary′ you can use theln as iHustrated.
Be carefu‖ some filters wi‖ possibly produce
ghostimages.
OA 481nlTlfilter can be attached on the CA―
35{50。8mm/2")or on the■ Mount DX―
WR。 丁he filter vvith large attaching frame
can not be attached on these accessories
because of sma‖ spaces.
An 82「lln filter can be attached on the
corrector ceH.
Mirror Cell
Filter
A58nlrn filter can
Reducer‐ CR O.73X.
be attached on the
58nlrn Filter Reducer― CR O。 73X
48mm
丁
―
Mount DX/WR
Pttmary
Corrector Cell
(50.8mm/2"
Filter
‑17‑

■SOME PRECAU丁10NS ON IMAGING
●丁
riaHmaging
Afterthe imaging package has be attached
and focused precisely′ itis a good idea to
take a 5‐ rrlinute test exposure makes cer‐
tain that everything is correctly set.
●
Guided lmaging
in the optical system which can produce
sharpestilnages as CCA‐ 250′ slight guiding
error vviH Inake images deforrned口 丁
here―
fore′ precise tracking and guiding are
required.in the CCA‐ 250′ its f‐ ratio is so
darkerthat a long exposure is necessary for
irnaging.lf there、〃
ould be some plays and
rattles around the guiding systeΠ l′ no pre―
cise guiding can be expected.Please use
firlnly built guiding systeme
●Back Focus
Focusing in thisinstrumentis rnade by rnov‐
ing the secondary rnirror by a rnoton ln or‐
der to have the best possible capability of
the instrument′ the various parts forimag‐
ing are attached correctly according to the
designed backfocus.Study the systena chart
very carefu‖ y and attach yourimaging pact
age strictly according to the back focus.
●
Tube Current
When the CCA‐250 is taken out′ there will
be air currents inside the tube that vvi‖ dis‐
tortimagingo Soritis necessary to、 Ⅳait until
the temperature inside and outside the tube
is equal口 When the telescope is brought
outsiderthe temperature inside the tube、 Ⅳill
be higherthan the outside air.
So′ there will be active air currents inside
the tube。 One source ofthe turbulence in
side the tube is the heat radiated by the
primary ITlirror as it cools.丁 his temperature
equalization process should take about one
houn
∠R Cautions
When imaging at high lnagnification′
pay careful attention to balance.Rebal―
ance the telescope when the obiectis
placed at the center ofthe camera.lf
the telescope is rnoved to another ob‐
leCt′ then rebalance itin the position in
which the:maging is taken.
Neverloosen the clamps ofthe rnount
when the telescope is unbalanced.
A‖ the clamps should be tight afterthe
instrumentis balanced.Otherwise′ the
instrument will possibly swing and
cause damageロ
‑18‑

ACCESSORIES FOR IMACING
ln orderto image with CCA‐ 250a、〃ide range of
optical accessories and spacers are available that
will produce outstanding images。
■
Reducer― CR O.73X
Reducer‐ CR O.73X changes the focallength
to 910mm(f/3.6).lmaging with a DSLR
needs the foHowing accessories as i‖ us‐
trated.
Camera An」 e A uster
(CAA)
RD― EXtt R:ng
Specs:
Focallength
Focal ratio
lrnage circle
910mm
f/3.6
38mm
Reducer―CR O.73X 丁
―
Mount DX―WR DSLR
Coupling(丁 W)
Reducel― CRO.73X
RD― EX丁
‑19‑
Coupling(丁 W)

■
645 Reducer― CA O。 72X
645 Reducer‐ CA O。72X which produces a
601TllTl image circle is suitable to be used
with large chip CCD cameras and fu‖ frarrle
35nlm DSLR' so as illustrated belowロ
Specs:
Focallength
Focal ratio
lrnage circle
Coupling(丁W)
890rnrrl
f/3.6
60mm
丁
―
Mount DX―WR DSLR
A●ust::ReducerCA O.72X AUX.Ring
Camera Angle
(CAA)
645 Reducer― CA O.72X
AUX.Ring
Camera Angle A uster
(CAA)
‑20‑
Coupling(丁 W)