Celestron G-9.25 User Manual
1
The G-9
Model #11037
/
4
INSTRUCTION MANUAL
▲▲
INTRODUCTION INTRODUCTION
▲
INTRODUCTION
▲▲
INTRODUCTION INTRODUCTION
A Word of Caution .......................................................................................................................... 2
The Schmidt-Cassegrain Optical System ...........................................................................................2
▲▲
ASSEMBLING YOUR ASSEMBLING YOUR
▲
ASSEMBLING YOUR
▲▲
ASSEMBLING YOUR ASSEMBLING YOUR
The The
The
The The
Assembling the CG-5 EquatorialMount.............................................................. 6Assembling the CG-5 EquatorialMount.............................................................. 6
Assembling the CG-5 EquatorialMount.............................................................. 6
Assembling the CG-5 EquatorialMount.............................................................. 6Assembling the CG-5 EquatorialMount.............................................................. 6
G-9G-9
G-9
G-9G-9
11
1
11
//
....................................................................................................................................................................................................................................................................................................................................................................................................................
/
..........................................................................................................................................................................................................
....................................................................................................................................................................................................................................................................................................................................................................................................................
//
44
4
44
Setting Up the Tripod ......................................................................................................... 6
Adjusting the Tripod Height ................................................................................................ 6
Attaching the Accessory Tray ........................................................................................... 7
Attaching the Equatorial Mount ......................................................................................... 8
Attaching the Telescope to the Mount .............................................................................. 12
Removing the Lens Cap ....................................................................................................13
Balancing the Telescope in R.A. ....................................................................................... 14
Balancing the Telescope in DEC ...................................................................................... 14
Adjusting the Mount in Altitude ......................................................................................... 15
Adjusting the Mount in Azimuth ........................................................................................15
Disassembling and Transporting Your G-9
Storing Your G-9
TT
ABLE OF CONTENTSABLE OF CONTENTS
T
ABLE OF CONTENTS
TT
ABLE OF CONTENTSABLE OF CONTENTS
..........................................................................................................................................................................................................................................................
.............................................................................................................................
..........................................................................................................................................................................................................................................................
11
1
11
//
G-9G-9
G-9
G-9G-9
......................................................................................................................................................................................................................................................................................................................................
/
...................................................................................................................................................................
......................................................................................................................................................................................................................................................................................................................................
//
44
4
44
Attaching the R.A. Slow Motion Knob ................................................................... 9
Attaching the Declination Slow Motion Knob........................................................ 10
Attaching the Counterweight Bar and Counterweights ..........................................11
1
/
......................................................................................................... 16
1
/
................................................................................................................................................................... 16
4
4
11
1
11
44
4
44
55
5
55
▲▲
TELESCOPE BASICS TELESCOPE BASICS
▲
TELESCOPE BASICS
▲▲
TELESCOPE BASICS TELESCOPE BASICS
Attaching the Accessories ...............................................................................................................17
The Visual Back ................................................................................................................17
The Star Diagonal ............................................................................................................. 17
The Eyepiece ....................................................................................................................18
Image Orientation .......................................................................................................................... 19
Focusing ........................................................................................................................................20
Aligning the Finder ........................................................................................................................21
Your First Look .............................................................................................................................22
Daytime Observing ........................................................................................................... 22
Nighttime Observing ......................................................................................................... 23
Calculating Magnification ............................................................................................................... 24
Determining Field of View .............................................................................................................24
General Observing Hints ................................................................................................................25
General Photography Hints .............................................................................................................25
▲ ▲
ASTRONOMY BASICS ASTRONOMY BASICS
▲
ASTRONOMY BASICS
▲ ▲
ASTRONOMY BASICS ASTRONOMY BASICS
The Celestial Coordinate System .....................................................................................................27
Motion of the Stars .........................................................................................................................28
Polar Alignment .............................................................................................................................28
Finding the Pole ............................................................................................................................. 29
Latitude Scales ..................................................................................................................30
Pointing at Polaris .............................................................................................................31
Declination Drift ..............................................................................................................32
Polar Alignment Finders .................................................................................................... 33
Aligning the R.A. Setting Circle ......................................................................................... 33
..........................................................................................................................................................................................................................................
.....................................................................................................................
..........................................................................................................................................................................................................................................
......................................................................................................................................................................................................................................
...................................................................................................................
......................................................................................................................................................................................................................................
1717
17
1717
2626
26
2626
Table of Contents • i
▲ ▲
CELESTIAL OBSERVING CELESTIAL OBSERVING
▲
CELESTIAL OBSERVING
▲ ▲
CELESTIAL OBSERVING CELESTIAL OBSERVING
Observing the Moon .......................................................................................................................34
Observing the Planets .....................................................................................................................34
Observing the Sun ..........................................................................................................................35
Observing Deep-Sky Objects ...........................................................................................................36
Using the Setting Circles .................................................................................................... 36
Star Hopping ..................................................................................................................... 37
Viewing Conditions ........................................................................................................................39
Transparency ....................................................................................................................39
Sky Illumination ............................................................................................................... 39
Seeing ...............................................................................................................................39
▲ ▲
CELESTIAL PHOTOGRAPHY CELESTIAL PHOTOGRAPHY
▲
CELESTIAL PHOTOGRAPHY
▲ ▲
CELESTIAL PHOTOGRAPHY CELESTIAL PHOTOGRAPHY
Short Exposure Prime Focus ...........................................................................................................42
Piggyback ......................................................................................................................................44
Eyepiece Projection ........................................................................................................................46
Long Exposure Prime Focus ........................................................................................................... 48
▲▲
TELESCOPE MAINTENANCE TELESCOPE MAINTENANCE
▲
TELESCOPE MAINTENANCE
▲▲
TELESCOPE MAINTENANCE TELESCOPE MAINTENANCE
Care and Cleaning of the Optics .......................................................................................................50
Collimation ...................................................................................................................................50
Technical Specifications .................................................................................................................52
......................................................................................................................................................................................................................
...........................................................................................................
......................................................................................................................................................................................................................
........................................................................................................................................................................................................
....................................................................................................
........................................................................................................................................................................................................
........................................................................................................................................................................................................
....................................................................................................
........................................................................................................................................................................................................
3434
34
3434
4141
41
4141
5050
50
5050
▲ ▲
OPTIONAL ACCESSORIES OPTIONAL ACCESSORIES
▲
OPTIONAL ACCESSORIES
▲ ▲
OPTIONAL ACCESSORIES OPTIONAL ACCESSORIES
▲▲
THE MESSIER CATALOG THE MESSIER CATALOG
▲
THE MESSIER CATALOG
▲▲
THE MESSIER CATALOG THE MESSIER CATALOG
▲▲
LIST OF BRIGHT STARS LIST OF BRIGHT STARS
▲
LIST OF BRIGHT STARS
▲▲
LIST OF BRIGHT STARS LIST OF BRIGHT STARS
▲▲
FOR FURTHER READING FOR FURTHER READING
▲
FOR FURTHER READING
▲▲
FOR FURTHER READING FOR FURTHER READING
....................................................................................................................................................................................................................
..........................................................................................................
....................................................................................................................................................................................................................
........................................................................................................................................................................................................................
............................................................................................................
........................................................................................................................................................................................................................
............................................................................................................................................................................................................................
..............................................................................................................
............................................................................................................................................................................................................................
......................................................................................................................................................................................................................
...........................................................................................................
......................................................................................................................................................................................................................
5353
53
5353
5757
57
5757
6060
60
6060
6161
61
6161
ii • Table of Contents
INTRODUCTIONINTRODUCTION
INTRODUCTION
INTRODUCTIONINTRODUCTION
Welcome to the Celestron world of amateur astronomy! For more than a quarter
of a century, Celestron has provided amateur astronomers with the tools needed to
explore the universe. The Celestron G-9
1
/
continues in this proud tradition
4
combining large aperture optics with ease of use and portability. With a mirror
diameter of 9.25 inches, your Celestron has a light gathering power of 1,126 times
that of the unaided human eye. Yet despite its large aperture, the Celestron G-9 1/
optical system is extremely compact and portable because it utilizes the Schmidt-
Cassegrain design. This means you can take your Celestron G-9 1/
to the moun-
4
tains or desert or wherever you observe.
The Celestron G-9 1/
is made of the highest quality materials to ensure stability
4
and durability. All this adds up to a telescope that gives you a lifetime of pleasure
with a minimal amount of maintenance. And, your Celestron G-9 1/
is versatile -
4
it grows as your interest in astronomy grows.
Your Celestron G-9 1/
is not limited to astronomical viewing alone. It can also be
4
used for terrestrial viewing to study the world around you. All you need to do is
take the time to familiarize yourself with your Celestron telescope and its opera-
tion.
Read the assembly instructions through completely before you attempt to set up
your Celestron G-9 1/
telescope. Then, once you’ve set up your Celestron G-9 1/
4
you should read the section on ‘Telescope Basics’ before you take it outside and
4
4
use it. This will ensure that you are familiar with your telescope before you try to
use it under a dark sky. Since it will take a few observing sessions to familiarize
yourself with your Celestron G-9 1/
you should keep this manual handy until you
4
have fully mastered your telescope’s operation. After that, save the manual for
future reference.
Introduction • 1
A Word of CautionA Word of Caution
A Word of Caution
A Word of CautionA Word of Caution
Your G-9 1/
tions. However, there are a few things to consider before using your telescope that
will ensure your safety and protect your equipment.
telescope is designed to give you hours of fun and rewarding observa-
4
WARNING !WARNING !
WARNING !
WARNING !WARNING !
NEVER LOOK DIRECTLY AT THE SUN WITH THE NAKEDNEVER LOOK DIRECTLY AT THE SUN WITH THE NAKED
NEVER LOOK DIRECTLY AT THE SUN WITH THE NAKED
NEVER LOOK DIRECTLY AT THE SUN WITH THE NAKEDNEVER LOOK DIRECTLY AT THE SUN WITH THE NAKED
EYE OR WITH A TELESCOPE. PERMANENT AND IRRE-EYE OR WITH A TELESCOPE. PERMANENT AND IRRE-
EYE OR WITH A TELESCOPE. PERMANENT AND IRRE-
EYE OR WITH A TELESCOPE. PERMANENT AND IRRE-EYE OR WITH A TELESCOPE. PERMANENT AND IRREVERSIBLE EYE DAMAGE MAY RESULT.VERSIBLE EYE DAMAGE MAY RESULT.
VERSIBLE EYE DAMAGE MAY RESULT.
VERSIBLE EYE DAMAGE MAY RESULT.VERSIBLE EYE DAMAGE MAY RESULT.
NEVER USE YOUR TELESCOPE TO PROJECT AN IMAGE OFNEVER USE YOUR TELESCOPE TO PROJECT AN IMAGE OF
NEVER USE YOUR TELESCOPE TO PROJECT AN IMAGE OF
NEVER USE YOUR TELESCOPE TO PROJECT AN IMAGE OFNEVER USE YOUR TELESCOPE TO PROJECT AN IMAGE OF
THE SUN ONTO ANY SURFACE. INTERNAL HEAT BUILD-THE SUN ONTO ANY SURFACE. INTERNAL HEAT BUILD-
THE SUN ONTO ANY SURFACE. INTERNAL HEAT BUILD-
THE SUN ONTO ANY SURFACE. INTERNAL HEAT BUILD-THE SUN ONTO ANY SURFACE. INTERNAL HEAT BUILDUP CAN DAMAGE THE TELESCOPE AND/OR ANY ACCES-UP CAN DAMAGE THE TELESCOPE AND/OR ANY ACCES-
UP CAN DAMAGE THE TELESCOPE AND/OR ANY ACCES-
UP CAN DAMAGE THE TELESCOPE AND/OR ANY ACCES-UP CAN DAMAGE THE TELESCOPE AND/OR ANY ACCESSORIES ATTACHED TO IT.SORIES ATTACHED TO IT.
SORIES ATTACHED TO IT.
SORIES ATTACHED TO IT.SORIES ATTACHED TO IT.
NEVER USE AN EYEPIECE SOLAR FILTER OR A HERSCHELNEVER USE AN EYEPIECE SOLAR FILTER OR A HERSCHEL
NEVER USE AN EYEPIECE SOLAR FILTER OR A HERSCHEL
NEVER USE AN EYEPIECE SOLAR FILTER OR A HERSCHELNEVER USE AN EYEPIECE SOLAR FILTER OR A HERSCHEL
WEDGE. INTERNAL HEAT BUILD-UP INSIDE THE TELE-WEDGE. INTERNAL HEAT BUILD-UP INSIDE THE TELE-
WEDGE. INTERNAL HEAT BUILD-UP INSIDE THE TELE-
WEDGE. INTERNAL HEAT BUILD-UP INSIDE THE TELE-WEDGE. INTERNAL HEAT BUILD-UP INSIDE THE TELESCOPE CAN CAUSE THESE DEVICES TO CRACK OR BREAK,SCOPE CAN CAUSE THESE DEVICES TO CRACK OR BREAK,
SCOPE CAN CAUSE THESE DEVICES TO CRACK OR BREAK,
SCOPE CAN CAUSE THESE DEVICES TO CRACK OR BREAK,SCOPE CAN CAUSE THESE DEVICES TO CRACK OR BREAK,
ALLOWING UNFILTERED SUNLIGHT TO PASS THROUGHALLOWING UNFILTERED SUNLIGHT TO PASS THROUGH
ALLOWING UNFILTERED SUNLIGHT TO PASS THROUGH
ALLOWING UNFILTERED SUNLIGHT TO PASS THROUGHALLOWING UNFILTERED SUNLIGHT TO PASS THROUGH
TO THE EYE.TO THE EYE.
TO THE EYE.
TO THE EYE.TO THE EYE.
NEVER LEAVE THE TELESCOPE UNSUPERVISED, EITHERNEVER LEAVE THE TELESCOPE UNSUPERVISED, EITHER
NEVER LEAVE THE TELESCOPE UNSUPERVISED, EITHER
NEVER LEAVE THE TELESCOPE UNSUPERVISED, EITHERNEVER LEAVE THE TELESCOPE UNSUPERVISED, EITHER
WHEN CHILDREN ARE PRESENT OR ADULTS WHO MAYWHEN CHILDREN ARE PRESENT OR ADULTS WHO MAY
WHEN CHILDREN ARE PRESENT OR ADULTS WHO MAY
WHEN CHILDREN ARE PRESENT OR ADULTS WHO MAYWHEN CHILDREN ARE PRESENT OR ADULTS WHO MAY
NOT BE FAMILIAR WITH THE CORRECT OPERATINGNOT BE FAMILIAR WITH THE CORRECT OPERATING
NOT BE FAMILIAR WITH THE CORRECT OPERATING
NOT BE FAMILIAR WITH THE CORRECT OPERATINGNOT BE FAMILIAR WITH THE CORRECT OPERATING
PROCEDURES OF YOUR TELESCOPE.PROCEDURES OF YOUR TELESCOPE.
PROCEDURES OF YOUR TELESCOPE.
PROCEDURES OF YOUR TELESCOPE.PROCEDURES OF YOUR TELESCOPE.
NEVER POINT YOUR TELESCOPE AT THE SUN UNLESSNEVER POINT YOUR TELESCOPE AT THE SUN UNLESS
NEVER POINT YOUR TELESCOPE AT THE SUN UNLESS
NEVER POINT YOUR TELESCOPE AT THE SUN UNLESSNEVER POINT YOUR TELESCOPE AT THE SUN UNLESS
YOU HAVE THE PROPER SOLAR FILTER. WHEN USINGYOU HAVE THE PROPER SOLAR FILTER. WHEN USING
YOU HAVE THE PROPER SOLAR FILTER. WHEN USING
YOU HAVE THE PROPER SOLAR FILTER. WHEN USINGYOU HAVE THE PROPER SOLAR FILTER. WHEN USING
YOUR TELESCOPE WITH THE CORRECT SOLAR FILTER,YOUR TELESCOPE WITH THE CORRECT SOLAR FILTER,
YOUR TELESCOPE WITH THE CORRECT SOLAR FILTER,
YOUR TELESCOPE WITH THE CORRECT SOLAR FILTER,YOUR TELESCOPE WITH THE CORRECT SOLAR FILTER,
ALWAYS COVER THE FINDER. ALTHOUGH SMALL INALWAYS COVER THE FINDER. ALTHOUGH SMALL IN
ALWAYS COVER THE FINDER. ALTHOUGH SMALL IN
ALWAYS COVER THE FINDER. ALTHOUGH SMALL INALWAYS COVER THE FINDER. ALTHOUGH SMALL IN
APERTURE, THIS INSTRUMENT HAS ENOUGH LIGHTAPERTURE, THIS INSTRUMENT HAS ENOUGH LIGHT
APERTURE, THIS INSTRUMENT HAS ENOUGH LIGHT
APERTURE, THIS INSTRUMENT HAS ENOUGH LIGHTAPERTURE, THIS INSTRUMENT HAS ENOUGH LIGHT
GATHERING POWER TO CAUSE PERMANENT AND IRRE-GATHERING POWER TO CAUSE PERMANENT AND IRRE-
GATHERING POWER TO CAUSE PERMANENT AND IRRE-
GATHERING POWER TO CAUSE PERMANENT AND IRRE-GATHERING POWER TO CAUSE PERMANENT AND IRREVERSIBLE EYE DAMAGE. IN ADDITION, THE IMAGEVERSIBLE EYE DAMAGE. IN ADDITION, THE IMAGE
VERSIBLE EYE DAMAGE. IN ADDITION, THE IMAGE
VERSIBLE EYE DAMAGE. IN ADDITION, THE IMAGEVERSIBLE EYE DAMAGE. IN ADDITION, THE IMAGE
PROJECTED BY THE FINDER IS HOT ENOUGH TO BURNPROJECTED BY THE FINDER IS HOT ENOUGH TO BURN
PROJECTED BY THE FINDER IS HOT ENOUGH TO BURN
PROJECTED BY THE FINDER IS HOT ENOUGH TO BURNPROJECTED BY THE FINDER IS HOT ENOUGH TO BURN
SKIN OR CLOTHING.SKIN OR CLOTHING.
SKIN OR CLOTHING.
SKIN OR CLOTHING.SKIN OR CLOTHING.
The Schmidt-The Schmidt-
The Schmidt-
The Schmidt-The SchmidtCassegrainCassegrain
Cassegrain
CassegrainCassegrain
Optical SystemOptical System
Optical System
Optical SystemOptical System
2 • Introduction
A telescope is an instrument that collects and focuses light. The nature of the
optical design determines how the light is focused. Some telescopes, known
as refractors, use lenses while others, known as reflectors, use mirrors. The
Schmidt-Cassegrain optical system (or SCT for short) uses a combination of
mirrors and lenses and is referred to as a compound or catadioptric telescope. This
unique design offers large diameter optics while maintaining very short tube
lengths, making them extremely portable. The Schmidt-Cassegrain system
consists of a zero power corrector plate, a spherical primary mirror, and a secondary mirror. Once light rays enter the optical system, they travel the length of the
optical tube three times.
Inside the optical tube you will notice a black tube (not illustrated) that extends
out from the center hole in the primary mirror. This is the primary baffle tube
and it prevents stray light from passing through to the eyepiece or camera.
Figure 1-1
This cross-sectional diagram shows the light path of the Schmidt-Cassegrain optical
system. Note that the light rays travel the length of the telescope tube three times,
making this a compact optical design. Note that the curve of the corrector plate is
greatly exaggerated.
Introduction • 3
ASSEMBLING ASSEMBLING
ASSEMBLING
ASSEMBLING ASSEMBLING
Unpacking YourUnpacking Your
Unpacking Your
Unpacking YourUnpacking Your
G-9 1/4G-9 1/4
G-9 1/4
G-9 1/4G-9 1/4
YY
OUR OUR
Y
OUR
YY
OUR OUR
AT POLARIS CAT POLARIS C
AT POLARIS C
AT POLARIS CAT POLARIS C
The Celestron G-91/4 is a standard 9.25" Schmidt-Cassegrain telescope on a
German equatorial mount. The Celestron G-91/4 comes standard with
Starbright™ coatings, an enhanced multi-layer aluminum coating on the primary
and secondary mirrors for increased reflectivity. Also, the corrector plate is fully
coated to allow maximum light transmission. The Celestron G-91/4 is shipped in
two boxes. One contains the telescope optical tube and is accompanied by a box
that contains the standard accessories, which are:
• 26mm Plossl Ocular 1-1/4"
• Visual Back 1-1/4"
• Star Diagonal 1-1/4"
• 6x30mm Finder and Bracket
• Lens Cap
The second box contains the tripod, equatorial mount and the hardware needed to
set it up. Included are the:
• CG-5 German Equatorial Mount
• Counterweight Bar
• Two Counterweights (11 lbs each)
• Declination (DEC) Slow Motion Knob
• Right Ascension (R.A.) Slow Motion Knob
• Adjustable Aluminium Tripod
• Accessory Tray
G - 9 G - 9
G - 9 1/4
G - 9 G - 9
When setting up the telescope, find a large, clear area where the parts can be
laid out without fear of losing them. Start with the tripod and mount. Remove
the contents of the box and place them neatly on your work surface. Leave the
optical tube in its box until you are ready to attach it to the mount. Once your G-9
1
/4 has been unpacked and assembled, you will not need the shipping boxes for
everyday storage and transportation. However, you should save them in case you
decide to ship your telescope via a common carrier.
4 • The G-9 1/4
13
The G-9 The G-9
The G-9
The G-9 The G-9
11
1
11
//
/
//
44
4
44
1
12
11
10
9
2
3
4
5
6
8
7
Figure 2-1
1. Lens Cover 8. Accessory Tray
2. Dovetail Bar Clamp Knob 9. Latitude Adjustment Screw
3. R.A. Lock Lever 10. Star Diagonal
4. Counterweight Shaft 11. Eyepiece
5. Counterweights 12. Finderscope
6. Tripod 13. Optical Tube
7. Leg Extention Clamp
The G-9 1/4 • 5
Setting Up the TripodSetting Up the Tripod
Setting Up the Tripod
Setting Up the TripodSetting Up the Tripod
Adjusting the TripodAdjusting the Tripod
Adjusting the Tripod
Adjusting the TripodAdjusting the Tripod
HeightHeight
Height
HeightHeight
Assembling the CG-5 Equatorial Mount
(#91515)
The tripod comes fully assembled with the metal plate, called the tripod head, that
holds the legs together at the top. In addition, the brackets that support the
accessory tray are also attached to the tripod.
Stand the tripod upright and pull the tripod legs apart until the leg brace assembly
for the accessory tray is fully extended (see figure 2-2). The tripod will now stand
by itself. To increase the stability, tighten the bolts that hold the legs to the tripod
head (use the appropriate size wrench from the supplied set). This will help
minimize any flexure or wobble of the legs.
Once the tripod is set up, you can adjust the height at which it stands. To do
this:
1. Loosen the knob on the leg clamp so that the tripod leg can be adjusted.
2. Slide the center portion of the tripod leg away from the tripod head until it
is at the desired height.
3. Tighten the knobs on each leg clamp to hold the legs in place.
Tripod HeadTripod Head
Tripod Head
Tripod HeadTripod Head
Warning: The G-9
adjusting the tripod height. If you need to make fine adjustments to the tripod while
the scope is mounted, be very careful because it is easy to accidentally knock the
system over!
1
/4 is quite heavy. Because of this, great care should be taken when
Figure 2-2
6 • The G-9 1/4
Attaching the AccessoryAttaching the Accessory
Attaching the Accessory
Attaching the AccessoryAttaching the Accessory
TrayTray
Tray
TrayTray
With the tripod set up, you are ready to attach the accessory tray to the tripod.
There are three wing bolts that hold the accessory tray to the bracket.
1. Locate the three wing bolts.
2. Place the accessory tray over the bracket and position it so the thread
holes in the accessory tray are above the slotted holes in the bracket.
3. Insert the wing bolts up through the slotted holes in the bracket (see figure
2-3).
4. Thread the wing bolts into the holes in the accessory tray.
5. Tighten the wing bolts fully.
WingWing
Wing
WingWing
BoltBolt
Bolt
BoltBolt
Figure 2-3Figure 2-3
Figure 2-3
Figure 2-3Figure 2-3
The G-9 1/4 • 7
Attaching the EquatorialAttaching the Equatorial
Attaching the Equatorial
Attaching the EquatorialAttaching the Equatorial
MountMount
Mount
MountMount
With the accessory tray in place, the tripod will be much more stable making it
easier to attach the mount and telescope.
The equatorial mount allows you to tilt the telescope’s axis of rotation so that you
can track the stars as they move across the sky. The CG-5 mount is a German
equatorial mount that attaches to the tripod head (i.e., metal plate on the tripod).
On one side of the plate there is an “N” which signifies north. This side of the
tripod will face north when setting up for an astronomical observing session.
Above the “N” is a peg about 3/4" high that points straight up. To attach the
equatorial head:
1. Locate the azimuth adjustment screws on the equatorial mount.
2. Retract the screws so they no longer extend into the azimuth housing
(rectangular extrusion) on the mount.
they are needed later for polar alignment.they are needed later for polar alignment.
they are needed later for polar alignment.
they are needed later for polar alignment.they are needed later for polar alignment.
3. Hold the equatorial mount over the tripod head so that the azimuth housing
is above the metal peg.
4. Place the equatorial mount on the tripod head so that the two are flush.
5. Tighten the knob on the underside of the tripod head to hold the equatorial
mount firmly in place. The knob is already attached and can
removed.
Do NOT remove the screws sinceDo NOT remove the screws since
Do NOT remove the screws since
Do NOT remove the screws sinceDo NOT remove the screws since
NOTNOT
NOT be
NOTNOT
8 • The G-9 1/4
Figure 2-4Figure 2-4
Figure 2-4
Figure 2-4Figure 2-4
Attaching the R.A. Slow Motion KnobAttaching the R.A. Slow Motion Knob
Attaching the R.A. Slow Motion Knob
Attaching the R.A. Slow Motion KnobAttaching the R.A. Slow Motion Knob
With the mount securely in place, you are ready to attach some of the accessories
(the telescope tube will be added last). Start with the Right Ascension (R.A.) slow
motion knob. The R.A. slow motion knob allows you to make fine pointing
adjustments in the direction the telescope is aiming (once it is attached to the
mount). To install the knob:
1. Locate the hard plastic shell under the R.A. shafts.
2. Remove either of the two oval tabs by pulling tightly.
3. Line up the flat area on the inner portion of the R.A. slow motion knob with
the flat area on the R.A. shaft (see figure 2-5).
4. Slide the R.A. slow motion knob onto the R.A. shaft.
The knob is a tension fit, so sliding it on holds it in place. As mentioned
above, there are two R.A. shafts, one on either side of the mount. It makes no
difference which shaft you use since both work the same. Use whichever one
you find more convenient. If, after a few observing sessions, you find the R.A.
slow motion knob is more accessible from the other side, pull firmly to remove the
knob, then install it on the opposite side.
Figure 2-5Figure 2-5
Figure 2-5
Figure 2-5Figure 2-5
The G-9 1/4 • 9
Attaching the Declination Slow Motion Knob
Like the R.A. slow motion knob, the DEC slow motion knob allows you to make
fine pointing adjustments in the direction the telescope is pointed.
The DEC slow motion knob attaches in the same manner as the R.A. knob.
The shaft that the DEC slow motion knob fits over is toward the top of the
mount, just below the telescope mounting platform. Once again, you have two
shafts to choose from. Use the shaft that is pointing toward the ground. This
makes it easy to reach while looking through the telescope, something which
is quite important when you are observing.
1. Line up the flat area on the inner portion of the DEC slow motion knob with
the flat area on the DEC shaft.
2. Slide the DEC slow motion knob over the DEC shaft (see figure 2-6).
Mounting Platform
Mounting Platform
Safety Screw
DEC Slow Motion
Knob
R.A. Setting
Circle
Polar Housing
Cover
Altitude Adjustment
Control
Telescope
Mounting Screw
DEC Lock
Lever
RA Lock
Lever
Declination Setting
Circle
R.A. Slow Motion
Knob
Azimuth Adjustment
Controls
Figure 2-6
10 • The G-9 1/4
Attaching the Counterweight Bar and Counterweights
The last item to be mounted before the telescope tube is the counterweight bar and
counterweights. Used to balanced the telescope, the counterweight bar attaches to
the opposite side of the mount as the telescope. To install the counterweight bar:
1. Retract the counterweight bar lock nut by turning it counterclockwise. This
will expose the threads on the end of the counterweight bar.
2. Thread the counterweight bar into the mount completely. Once again,
threads into the mount opposite the telescopethreads into the mount opposite the telescope
threads into the mount opposite the telescope (see figure 2-7).
threads into the mount opposite the telescopethreads into the mount opposite the telescope
3. Tighten the counterweight bar lock nut fully for added support.
The counterweight bar is now installed. With the counterweight bar in place,
you are ready to attach the counterweights.
1. Lock the DEC clamp to hold the mount in place.
2. Remove the safety thumbscrew on the end of the counterweight bar.
3. Loosen the set screw on the counterweight itself so that the central hole of
the counterweight is unobstructed.
4. Slide the counterweight onto the counterweight bar. Move it high enough
to allow room for the second weight (see figure 2-7).
5. Tighten the set screw on the counterweight to hold it in position.
6. Repeat this process for the second weight.
7. Replace the safety thumbscrew on the end of the counterweight bar. The
thumbscrew will prevent the counterweights from sliding off the bar should
they ever become loose.
itit
it
itit
Figure 2-7
The G-9 1/4 • 11
Attaching the TelescopeAttaching the Telescope
Attaching the Telescope
Attaching the TelescopeAttaching the Telescope to the Mountto the Mount
to the Mount
to the Mountto the Mount
NOTE:NOTE:
NOTE: Never loosen any of the knobs on the telescope tube or mount. Also, be sure
NOTE:NOTE:
With the mount fully assembled, you are ready to attach the telescope to the
mount.
Before you attach the optical tube, fully tighten the right ascension andBefore you attach the optical tube, fully tighten the right ascension and
•
Before you attach the optical tube, fully tighten the right ascension and
Before you attach the optical tube, fully tighten the right ascension andBefore you attach the optical tube, fully tighten the right ascension and
declination clamps. This will prevent the telescope from movingdeclination clamps. This will prevent the telescope from moving
declination clamps. This will prevent the telescope from moving
declination clamps. This will prevent the telescope from movingdeclination clamps. This will prevent the telescope from moving
suddenly once attached to the mount.suddenly once attached to the mount.
suddenly once attached to the mount.
suddenly once attached to the mount.suddenly once attached to the mount.
1. Loosen the hand knob on the side of the CG-5 mount.
2. Slide the dovetail bar that is attached to the telescope onto the CG-5
mount (see figure 2-8).
3. Tighten the knob on the CG-5 mount to hold the telescope in place.
that the corrector end of the telescope is pointing away from the ground at all
times.
12 • The G-9 1/4
Figure 2-8
This illustration shows the correct mounting procedure for the optical tube onto the CG-5
mount. The dovetail slide bar has been attached to the telescope tube and is ready to
attach to the CG-5 mount.
Balancing the Telescope
in R.A.
To eliminate undue stress on the mount, the telescope should be properly
balanced around the polar axis. In addition, proper balancing is crucial for
accurate tracking if using an optional motor drive. To balance the mount:
1. Release the R.A. Clamp and position the telescope off to one side of the
mount (make sure that the balance bracket thumbscrew is tight). The
counterweight bar will extend horizontally on the opposite side of the
mount (see figure 2-9).
2. Release the telescope — GRADUALLY — to see which way the telescope
“rolls.”
3. Loosen the set screw on one or both counterweights.
4. Move the counterweights to a point where they balance the telescope (i.e.,
it remains stationary when the R.A. clamp is released).
5. Tighten the set screw to hold the counterweight(s) in place.
These are general balance instructions and will reduce undue stress on the
mount. When taking astrophotographs, this balance process should be done
for the specific area at which the telescope is pointing.
R.A. CLAMP
Figure 2-9
The telescope should be balanced after all the standard accessories (i.e., star diagonal,
eyepiece, etc.) have been attached to the telescope. The correct procedure for attaching
these accessories is discussed in the section on “Telescope Basics.”
The G-9 1/4 • 13
Balancing the Telescope
in DEC
The telescope should also be balanced on the declination axis to prevent any
sudden motions when the DEC clamp is released. To balance the telescope in
DEC:
1. Release the R.A. clamp and rotate the telescope so that it is on one side
of the mount (i.e., as described in the previous section on balancing the
telescope in R.A.).
2. Lock the R.A. clamp to hold the telescope in place.
3. Release the DEC clamp and rotate the telescope until the tube is parallel
to the ground (see figure 2-10).
4. Release the tube — GRADUALLY — to see which way it rotates around
the declination axis. DO NOT LET GO OF THE TELESCOPE TUBE
COMPLETELY!
5. Slightly loosen the balance bracket thumbscrew and slide the telescope
either forward or backward until it remains stationary when the DEC clamp
is released. Do NOT let go of the telescope tube while the balance
bracket thumbscrew is loose.
6. Tighten the thumbscrew firmly to hold the telescope in place.
Like the R.A. balance, these are general balance instructions and will reduce
undue stress on the mount. When taking astrophotographs, this balance
process should be done for the specific area at which the telescope is pointing.
14 • The G-9 1/4
Figure 2-10
As with R.A., the telescope should be balanced in DEC after all the standard accessories
(i.e., star diagonal, eyepiece, etc.) have been attached to the telescope.
Adjusting the Mount
in Altitude
For the purpose of polar alignment, there are two directions in which the
mount can be adjusted; vertically, which is called altitude and horizontally,
which is called azimuth. There are several ways to align on the celestial pole,
many of which are discussed later in this manual. This section simply covers
the correct movement of the mount during the polar alignment process. To
adjust the mount in altitude (i.e., raise or lower the angle of the polar axis), turn
the altitude adjustment screw:
• Turning the knob clockwise increases the angle at which the polar axis is
pointing
• Turning the handle counterclockwise lowers the angle at which the polar
axis is pointing.
The latitude adjustment on the CG-5 mount has a range of 40°, starting at 20°
going up to 60°.
Adjusting the Mount
in Azimuth
For rough adjustments in azimuth, simply pick up the telescope and tripod and
move it until the R.A. axis is roughly pointed towards north. For fine adjustments in azimuth:
1. Turn the azimuth adjustment screws located on either side of the azimuth
housing. While standing behind the telescope, the knobs are on the front
of the mount.
• Turning the right adjustment knob clockwise moves the mount toward the
right.
• Turning the left adjustment knob clockwise moves the mount to the left.
Both screws push off of the peg on the tripod head, which means you may
have to loosen one screw while tightening the other. The screw that holds the
equatorial mount to the tripod may have to be loosened slightly.
Figure 2-11
The G-9 1/4 • 15
Disassembling and
Transporting Your
G-9 1/
4
The entire telescope and mount can be picked up and carried outside for a
1
/
casual observing session. If, however, you want to transport your G-9
4
to a
remote observing location, you must partially disassemble it. Here’s how:
1. Remove the telescope from the equatorial mount. Return it to the shipping
carton to ensure safe transportation.
2. Remove the three wing bolts that hold the accessory tray to the tripod.
3. Pull the accessory tray off the bracket.
4. Thread the wing bolts back onto the accessory tray once they are removed
from the bracket. This will eliminate the possibility of losing them.
Storing Your G-9 1/4
What Next?
5. Fold the tripod legs together and you are ready to transport your G-9 1/
4"
telescope.
The equatorial mount does NOT have to be removed if you are transporting the
telescope yourself. However, you may want to remove the counterweights from
the counterweight bar to lighten the mount.
If you are shipping the telescope via a common carrier, you should completely
disassemble the telescope and return all parts to their original shipping
container.
When not in use, your Celestron G-9
1
/
can be left fully assembled and set up.
4
However, all lens and eyepiece covers should be put back in place. The
opening to the rear cell must also be covered. This will reduce the amount of
dust build-up on the optical surfaces and reduce the number of times you need
to clean the instrument. You may want to return everything to its original
shipping container and store all the parts there. If this is the case, all optical
surfaces should still be covered to prevent dust build-up.
Now that you have completed assembling your G-9 1/
, you are ready to begin
4
attaching the accessories. Please turn to the section on “Telescope Basics” for
more information.
16 • The G-9 1/4
TELESCOPE BASICS
Once your telescope has been fully assembled, you are ready to attach the accessories and have a look. This section deals with basic telescope operations that are
common to all Celestron Schmidt-Cassegrain telescopes.
Attaching the Accessories
There are several accessories that come standard with all the Celestron SchmidtCassegrain telescopes. The installation and use of each of these is described in this
section.
The Visual Back
The visual back is the accessory that allows you to attach all visual accessories to
the telescope. The G-9 1/4 comes with the visual back installed. If it is not already on
the tube it can be attached as follows:
1 . Remove the rubber cover on the rear cell.
2 . Place the knurled slip ring on the visual back over the threads on the rear cell
(see figure 3-2).
3. Hold the visual back with the set screw in a convenient position and rotate the
knurled slip ring clockwise until tight.
Once this is done, you are ready to attach other accessories, such as eyepieces,
diagonal prisms, etc.
If you want to remove the visual back, rotate the slip ring counterclockwise until it is
free of the rear cell.
The Star Diagonal
The star diagonal uses a mirror that reflects the light at a right angle to the light path
of the telescope. This allows you to observe in positions that are physically more
comfortable than if you were to look straight through. To attach the star diagonal:
1 . Turn the set screw on the visual back until it no longer extends into (i.e., ob-
structs) its inner diameter of the visual back.
2 . Slide the chrome portion of the star diagonal into the visual back (see figure 3-2).
3. Tighten the set screw to hold the star diagonal in place.
If you wish to change the orientation of the star diagonal, loosen the set screw on the
visual back until the star diagonal rotates freely. Rotate the diagonal to the desired
position and tighten the set screw.
Telescope Basics • 17
Loading...