Celestron Ultima 11 User manual

THE CELESTRON ULTIMA 91/4
AND ULTIMA 11
INSTRUCTION MANUAL

Table of Contents
INTRODUCTION......................................................................................................................................... 4
HOW TO USE THIS MANUAL ............................................................................................................................ 4
THE SCHMIDT-CASSEGRAIN OPTICAL SYSTEM ................................................................................................ 6
ASSEMBLING YOUR ULTIMA 91/4AND 11........................................................................................... 7
SETTING UP THE TRIPOD.................................................................................................................................. 9
ADJUSTING THE TRIPOD HEIGHT.................................................................................................................... 10
INSTALLING THE DELUXE LATITUDE ADJUSTER............................................................................................. 11
Latitude Adjust Assembly Installation....................................................................................................... 11
Azimuth Adjust Assembly Procedure ........................................................................................................ 11
ATTACHING WEDGE TO TRIPOD..................................................................................................................... 13
ATTACHING THE TELESCOPE TO THE WEDGE................................................................................................. 14
INSTALLING THE FINDER ................................................................................................................................ 15
Attaching the Finder Bracket.................................................................................................................... 15
Attaching the Finder to the Bracket.......................................................................................................... 16
OPTIONAL ILLUMINATOR OPERATION ............................................................................................................ 17
Installing the Battery ................................................................................................................................ 17
Operating Information.............................................................................................................................. 17
INSTALLING THE VISUAL ACCESSORIES ......................................................................................................... 18
The Visual Back ........................................................................................................................................ 18
The Star Diagonal..................................................................................................................................... 18
The Eyepieces ........................................................................................................................................... 19
MOVING THE TELESCOPE IN R.A. AND DEC.................................................................................................. 19
ADJUSTING THE WEDGE ................................................................................................................................ 22
TRANSPORTING YOUR ULTIMA TELESCOPE ................................................................................................... 23
STORING YOUR ULTIMA TELESCOPE ............................................................................................................. 24
TELESCOPE BASICS ............................................................................................................................... 25
FOCUSING ...................................................................................................................................................... 25
ALIGNING THE FINDER SCOPE........................................................................................................................ 25
DAYTIME OBSERVING.................................................................................................................................... 26
NIGHTTIME OBSERVING................................................................................................................................. 26
CALCULATING MAGNIFICATION ..................................................................................................................... 27
DETERMINING FIELD OF VIEW ....................................................................................................................... 27
GENERAL OBSERVING HINTS ......................................................................................................................... 28
GENERAL PHOTOGRAPHY HINTS.................................................................................................................... 28
ASTRONOMY BASICS............................................................................................................................. 30
THE CELESTIAL COORDINATE SYSTEM .......................................................................................................... 30
MOTION OF THE STARS .................................................................................................................................. 31
POLAR ALIGNMENT ....................................................................................................................................... 32
Finding the Pole ....................................................................................................................................... 33
Latitude Scales.......................................................................................................................................... 34
Pointing at Polaris.................................................................................................................................... 35
Declination Drift....................................................................................................................................... 36
Aligning the RA Setting Circle.................................................................................................................. 37
USING THE DRIVE................................................................................................................................... 38
POWERING UP THE DRIVE.............................................................................................................................. 38

THE HAND CONTROLLER BUTTONS ............................................................................................................... 39
TRACKING RATE SELECTION.......................................................................................................................... 40
PERIODIC ERROR CORRECTION...................................................................................................................... 40
CONNECTORS................................................................................................................................................. 42
THE HAND CONTROLLER ............................................................................................................................... 43
REPLACING THE BATTERY ............................................................................................................................. 43
TROUBLE SHOOTING...................................................................................................................................... 44
CELESTIAL OBSERVING....................................................................................................................... 45
OBSERVING THE MOON ................................................................................................................................. 45
Lunar Observing Hints ............................................................................................................................. 45
OBSERVING THE PLANETS.............................................................................................................................. 45
Planetary Observing Hints ....................................................................................................................... 45
OBSERVING THE SUN ..................................................................................................................................... 45
Solar Observing Hints............................................................................................................................... 46
OBSERVING DEEP SKY OBJECTS.................................................................................................................... 46
Using the Setting Circles .......................................................................................................................... 46
Star Hopping............................................................................................................................................. 47
SEEING CONDITIONS ...................................................................................................................................... 49
Transparency ............................................................................................................................................ 49
Sky Illumination ........................................................................................................................................ 49
Seeing........................................................................................................................................................ 49
CELESTIAL PHOTOGRAPHY ............................................................................................................... 51
SHORT EXPOSURE PRIME FOCUS PHOTOGRAPHY .......................................................................................... 51
PIGGYBACK PHOTOGRAPHY........................................................................................................................... 52
EYEPIECE PROJECTION................................................................................................................................... 54
Effective Focal Length .............................................................................................................................. 55
Effective Magnification............................................................................................................................. 55
Effective f# or f-ratio................................................................................................................................. 56
LONG EXPOSURE PRIME FOCUS PHOTOGRAPHY ............................................................................................ 56
TELESCOPE MAINTENANCE ............................................................................................................... 58
CARE AND CLEANING OF THE OPTICS ............................................................................................................ 58
COLLIMATION ................................................................................................................................................ 58
OPTIONAL ACCESSORIES .................................................................................................................... 60
THE MESSIER CATALOG ...................................................................................................................... 64
LIST OF BRIGHT STARS ........................................................................................................................ 68
TECHNICAL SPECIFICATIONS............................................................................................................ 69
FURTHER READING ............................................................................................................................... 70

Telescope Basics4
INTRODUCTION
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 Ultima series telescopes
continue in this proud tradition combining large aperture optics with ease of use and portability. With
mirror diameters of 9.25 and 11 inches, your Celestron Ultima 91/4and 11 have a light gathering power of
1,126 and 1,593 times that of the unaided human eye respectively. Yet, their optical systems are extremely
compact and portable despite their large aperture because they utilize the Schmidt-Cassegrain design. This
means you can take your Ultima telescope to the mountains or desert or wherever you wish to observe.
The Ultima telescope is made of the highest quality materials to ensure stability and durability. All this
adds up to a telescope that gives you a lifetime of pleasure with a minimal amount of maintenance. And,
your Ultima telescope is versatile — it grows as your interest in astronomy grows.
But, your Celestron Ultima telescope is not limited to astronomical viewing alone. It can also be used for
terrestrial viewing to study the world around you. All you need to do is take the time to familiarize yourself
with your Ultima telescope and its operation.
HOW TO USE THIS MANUAL
This manual is designed to instruct you in the proper use of your Celestron Ultima telescope. This includes
assembly, initial use, and long term operation and maintenance. There are seven major sections to the
manual. The first section covers the proper procedure for setting up your Ultima telescope and includes
attaching the standard accessories.
The second section covers basic telescope operation. Topics include focusing, aligning the finder, and
taking your first look. The third section deals with the basics of astronomy which includes the celestial
coordinate system, the motions of the stars, and polar alignment. The fourth section describes how to use
the drive. The fifth section covers visual observing of the Moon, planets, and deep sky objects. The sixth
section deals with celestial photography covering all major forms working from the easiest to the most
difficult. The last major section is on telescope maintenance, specifically on cleaning and collimation.
After the major sections mentioned above, there is a partial list of optional accessories for the Ultima
telescope with a brief description of each and its intended purpose. The final part of this manual contains a
list of objects that can be observed through your Celestron Ultima telescope. Included are the coordinates
for each object, its brightness, and a code which indicates object type. There is also a list of bright stars for
aligning the setting circles.
Read the assembly instructions completely before you attempt to set up your Ultima 91/4or 11. Once you
have set up your Ultima telescope, read the section on "Telescope Basics" before using it outside. This will
ensure that you are familiar with your telescope before you use it under a dark sky.
Since it will take a few observing sessions to familiarize yourself with your Ultima telescope, you should
keep this manual handy until you have fully mastered your telescope's operation.
Your Ultima telescope is designed to give you hours of fun and rewarding observations. However, there are
a few things to consider before using your telescope that will ensure your safety and protect your
equipment.
NEVER LOOK DIRECTLY AT THE SUN WITH THE NAKED EYE OR WITH A TELESCOPE.
PERMANENT AND IRREVERSIBLE EYE DAMAGE MAY RESULT.

Telescope Basics 5
NEVER USE YOUR TELESCOPE TO PROJECT AN IMAGE OF THE SUN ONTO ANY SURFACE.
INTERNAL HEAT BUILD-UP CAN DAMAGE THE TELESCOPE AND/OR ANY ACCESSORIES
ATTACHED TO IT.
NEVER USE AN EYEPIECE SOLAR FILTER OR A HERSCHEL WEDGE. INTERNAL HEAT
BUILD-UP INSIDE THE TELESCOPE CAN CAUSE THESE DEVICES TO CRACK OR BREAK,
ALLOWING UNFILTERED SUNLIGHT TO PASS THROUGH TO THE EYE.
NEVER LEAVE THE TELESCOPE UNSUPERVISED, EITHER WHEN CHILDREN ARE PRESENT
OR ADULTS WHO MAY NOT BE FAMILIAR WITH THE CORRECT OPERATING PROCEDURES
OF YOUR TELESCOPE.
NEVER POINT YOUR TELESCOPE AT THE SUN UNLESS YOU HAVE THE PROPER SOLAR
FILTER. WHEN USING YOUR TELESCOPE WITH THE CORRECT SOLAR FILTER, ALWAYS
COVER THE FINDER. ALTHOUGH SMALL IN APERTURE, THIS INSTRUMENT HAS ENOUGH
LIGHT GATHERING POWER TO CAUSE PERMANENT AND IRREVERSIBLE EYE DAMAGE.
FURTHERMORE, THE IMAGE PROJECTED BY THE FINDER IS HOT ENOUGH TO BURN SKIN
OR CLOTHING.

Telescope Basics6
THE SCHMIDT-CASSEGRAIN OPTICAL SYSTEM
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 Schmidt-Cass 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 convex 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 without striking the primary or secondary mirrors.
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

Telescope Basics 7
ASSEMBLING YOUR ULTIMA 91/4AND 11
The Ultima 91/4and 11 are heavy-duty, fork mounted telescopes that uses a single motor Byers worm gear
drive and a 2-5/8" tapered polar shaft. For easy transportation, the Ultima telescopes have three carrying
handles; one on each fork tine and one on the rear cell. In addition, the Ultima comes standard with
StarbrightTM 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
Ultima 91/4(#11035 ) and the Ultima 11 (#11044) are shipped in four boxes. One contains the telescope
with most of the standard accessories, which are:
• 26mm Plössl Ocular 1-1/4" (Ultima 11)
• 25mm SMA Ocular 1-1/4” (Ultima 91/4)
• Visual Back 1-1/4"
• Reducer Plate (Ultima 11)
• Star Diagonal, Prism 1-1/4"
• Deluxe Latitude Adjuster Upgrade Kit (DLA)
• 7x50mm Polaris Finderscope with Bracket (Ultima 11)
• 6x30mm Finderscope with bracket (Ultima 91/4)
• Lens Cap
• Bolt Pack
• Allen Wrench
The second and third boxes contain the wedge and tripod which are also standard accessories. The Deluxe
Latitude Adjuster is not installed on the wedge. The fourth box contains additional accessories not included
inside the telescope case.
Both telescopes come with a heavy-duty wedge and an 11/4" star diagonal. The assembly procedure for both
scopes is identical. The differences between these models are the optical tube assemblies. The Ultima
telescope should be set up indoors the first time so that it is easy to identify the various parts and familiarize
yourself with the correct assembly procedure before attempting it outdoors.
Remove the wedge, tripod and telescope from their respective boxes. Remove all the accessories as well,
which are located in the box with the telescope. Since all parts are completely assembled, all you need to
do is attach the wedge to the tripod and the telescope to the wedge. Provided are two bolt packs (each
containing three bolts) for this purpose. Locate each pack and you are ready to begin.
Use the diagram on the following page (figure 2-1) to familiarize yourself with the various parts of your
telescope. When setting up your Ultima telescope, you must start with the tripod and work up from there.

Telescope Basics8
Figure 2-1
The Ultima telescope completely assembled. Use this illustration, and others throughout this manual,
to familiarize yourself with the various parts of your Ultima 91/4or Ultima 11 telescope.

Telescope Basics 9
SETTING UP THE TRIPOD
For maximum rigidity, the Celestron field tripod has a leg support bracket. This bracket fits snugly against
the tripod legs, increasing stability while reducing vibration and flexure. However, the tripod is shipped
with each arm of the leg support bracket in between the legs so the tripod legs can collapse. To set up the
tripod:
1. Hold the tripod with the head up and the legs pointed toward the ground.
2. Pull the legs away from the central column until they will not separate any further. A small stop on
the top of each tripod leg presses against the tripod head to indicate maximum separation.
3. Rotate the tension knob (located underneath the support bracket on the central column) clockwise
until it is close to the bottom of the central column.
4. Turn the leg support bracket until the cups on the end of each bracket are directly underneath each
leg.
5. Rotate the tension knob counterclockwise until the bracket is secure against the tripod legs. Do
not over tighten.
The tripod will now stand by itself. Once the wedge and telescope are attached to the tripod, readjust the
tension knob to ensure that the leg support bracket is snug. Once again, do not over tighten!

Telescope Basics10
ADJUSTING THE TRIPOD HEIGHT
The tripod that comes with your Ultima telescope is adjustable. To adjust the height at which the tripod
stands:
1. Loosen the extension clamp on one of the tripod legs (see figure 2-3).
2. Extend the leg to the desired height.
3. Tighten the extension clamp to hold the leg in place.
4. Repeat this process for each of the remaining legs.
You can do this while the tripod legs are still folded together.
Remember that the higher the tripod legs are extended, the less stable it is. For casual observing, this may
not pose a problem. However, if you plan on doing photography, the tripod should be set low to ensure
stability. A recommended height is to set the tripod in such a manner that you can look directly into the
eyepiece on the telescope with a diagonal while seated.

Telescope Basics 11
INSTALLING THE DELUXE LATITUDE ADJUSTER
Latitude Adjust Assembly Installation.
• Remove the screws marked A in figure 2-5 from both sides of the wedge.
• Place the wedge in front of you upright and with the Celestron logo facing you. Place the wedge on its
left side. There should be a hole right next to the fourth hex head screw. This is where the azimuth
adjust screw will go. Loosen all of the hex head screws on the side of the wedge which is upright now.
Loosen them about three turns. There is no need to remove them completely.
• On the back of the tilt plate there are four 1/4-20 tapped holes. Place an angle bracket on the lower set
of holes with the bracket facing up. Use two of the 1/4-20 screws to attach the bracket.
• Take the latitude adjust assembly, shown in figure 2-4, and place one end of the swivel pin in the hole
of the mounted angle bracket. Now take the second angle bracket and slip it over the exposed side of
the swivel pin and mount the bracket.
• The crossbar needs to be adjusted so that it lines up with and slips into the recess on the inside of the
wedge side plate. Rotate the cross bar on the adjust screw until it approximately lines up with the
recess on the lower side of the wedge. This is the one inch diameter counter sunk hole that looks silver
since it is not coated. It is facing up at you since the wedge is on its side.
• Since the upper plate is loose it can be moved to allow the crosssbar to fit into place. The upper and
lower ends of the crossbar should fit into the recesses on the sides of the wedge. If the top side doesn't
quite fit, rotate the adjust screw till it does.
• Tighten all the screws of the side plate and replace the screws marked A being sure to tighten down the
slotted Latitude Support Arms in figure 2-5. Be sure the nylon washers are between the Latitude
Support Arms and the side of the wedge.
Azimuth Adjust Assembly Procedure
• Remove the block assembly from the threaded rod of the Azimuth Adjust Assembly.
• Remove the collar from the threaded rod by loosening the set screw.
• Attach the block assembly to the bottom of the baseplate of the wedge using the 10-24 x 3/4” screw.
The tapped hole should be facing the toward the left side of the wedge if the wedge is upside down. Do
not tighten the screw all the way. The block assembly should be able to slide back and forth.
• Put one nylon washer on the threaded rod and place the rod through the hole on the side of the wedge.
• Once the threaded rod is through the side of the wedge, place the other nylon washer on and then the
lock collar on.
• Now thread the threaded rod into the tapped hole on the side of the block assembly.
• Push the handle of the threaded rod flush against the side of the wedge and place the lock collar against
the inside of the wedge.
• Tighten the set-screw in the collar.
• Now if you rotate the threaded rod, the block assembly should move. If it is hard to rotate, then loosen
the screw holding the block assembly to the baseplate of the wedge.

Telescope Basics12
Figure 2-4: Upgrade Kit for the Heavy Duty Wedge
Figure 2-5: Upgrade Kit installed on the Heavy Duty Wedge

Telescope Basics 13
ATTACHING WEDGE TO TRIPOD
Your Ultima 91/4and Ultima 11 telescopes have a clock drive built into the base to track the stars as they
move across the sky from east to west. This drive is useless, however, unless the telescope’s axis of rotation
is parallel to the Earth’s axis. The wedge, which comes standard with both telescopes, allows you to tilt the
Ultima’s axis of rotation. This process is known as polar alignment and is described in the section by the
same name. The wedge, like the tripod, is fully assembled and only needs to be attached to the tripod.
The tripod has six holes on its base for mounting equipment. Three of the holes are threaded with 5/16-18
threads and three of the holes are open. The three open holes are for mounting a different telescope in the
Celestron line. To mount a wedge to the tripod, the three threaded holes are used. But, since you are using
the wedge with the Deluxe Latitude Adjuster kit (included with the Ultima 91/4and 11) the azimuth
adjusting knob will hit one of the legs of the tripod. Because of this, the wedge needs to be rotated on the
tripod 120º. Inserts are provided with the wedge which fit into the open holes in the tripod head. The
inserts are threaded inside.
To attach the wedge to the tripod:
1. Place the black inserts in the open holes from underneath the tripod head. The inserts fit into the
tripod with the flange end down (see Figure2-5b).
2. Hold the wedge over the center post in the tripod. Rotate the wedge so the through holes of the
wedge line up with the threaded inserts in the tripod head. Notice that there is a pin on the bottom
of the wedge which protrudes from the azimuth adjusting block. The pin fits into one of the
existing threaded holes. You may need to rotate the wedge slightly back-and-forth to get the
azimuth block pin to fall into the existing threaded hole on the head of the tripod.
3. Insert the three 5/16-18x1 socket head cap screws and washers through the slotted holes in the
wedge and into the tripod head.
4. Tighten the bolts until the wedge does not move from side-to-side. These can be loosened later for
polar alignment.
Figure 2-5a
Top view of tripod head
Figure 2-5b
Front view of wedge and tripod head

Telescope Basics14
ATTACHING THE TELESCOPE TO THE WEDGE
With the wedge in place on the tripod, you are ready to mount the telescope on the wedge. The telescope
base fits directly onto the tilt plate of the wedge. Attaching the telescope to the wedge is the same for both
the Ultima 91/4and the Ultima 11 telescopes. To do this:
1. Lay the telescope on its side and locate the three threaded holes in the bottom of the drive base.
2. Partially insert one of the three (3/8-16x1) bolts with the hand tightening knob (supplied in the bolt
pack) into the hole that is opposite the rectangular portion of the drive base. The rectangular
portion of the base slides between the side plates on the wedge and rest near the top of the tripod.
3. Pick the telescope up by the fork tines and position it above the wedge. Orient it so that the
telescope is over the tripod with the base pointing toward the tilt plate as seen in figure 2-6.
4. Slide the bolt, which is threaded into the base, into the slot on the top of the tilt plate.
5. Tighten the bolt slightly so that the bottom of the drive base is flush with the tilt plate. Do not
tighten it fully or you will not be able to slide the base so that the other two bolts can be inserted.
(If you do not tighten the bolt at all, the drive base may be tilted slightly so that the remaining bolts
will not go in straight.)
6. Move the base of the telescope until the two remaining holes in the drive base line up with the
holes in the tilt plate.
7. Insert the two remaining bolts with knobs and tighten all three completely.
Figure 2-6 - With the hand tightening bolt installed in the drive base, slide the Ultima telescope onto
the tilt plate of the wedge.

Telescope Basics 15
INSTALLING THE FINDER
The Ultima 91/4comes with a 6x30 finderscope which has an 7° field-of-view. The Ultima 11 comes with a
7x50 finder, which has a 5° field of view. The specifications for a finderscope, 6x30 or 7x50, stand for the
magnification and the aperture, in millimeters, of the scope. So, a 6x30 finder magnifies six times and has a
30mm objective lens.
A finder helps you locate and center objects in the main field of your Ultima telescope. The Polaris 7x50
finder serves a dual purpose. First, it is used as a regular finder to help you locate and center objects in the
main field of your Ultima 11. Second, if you purchase the optional Illuminator (51614-IL) and the Polaris
Guiding Plate (60121), it can be used to polar align your telescope. To accomplish this, the finder has a
built-in reticle that indicates the distance between the North Star, Polaris, and the true celestial pole. The
Guide Plate is used to show the exact position of Polaris on the reticle for the date and time you are
observing.
To ensure that the finder and bracket are not damaged during shipping, they are not attached to the
telescope at the factory. Start by removing the finder and hardware from the plastic wrapper. Included are
the following:
Ultima 9 1/4
• 6x30mm Finderscope
• Rubber O-Ring
• Three Nylon Thumbscrews (10-24x1/2)
• Two Allen Head Screws (10-24x5/8)
Ultima 11
• 7x50mm Finderscope
• Reticle Housing with Eyepiece
• Rubber O-Ring
• Three Nylon Thumbscrews (10-24x1/2)
• Two Allen Head Screws (10-24x5/8")
Mounting the finder is a two-step process and is the same for the Ultima 91/4and 11. First you mount the
bracket to the telescope, then mount the finder in the bracket.
Attaching the Finder Bracket
1. Find the two holes in the rear cell of the telescope on the top left, when looking from the back of
the tube.
2. Remove the tape covering the two holes. The tape is there to prevent dust and moisture from
entering the optical tube before the finder is installed.
3. Place the finder bracket over the two holes. Orient the bracket so that the rings that hold the finder
are over the telescope tube, not the rear cell.
4. Insert the screws through the bracket and into the rear cell.
WARNING: If you remove the finderscope, do not thread the screws back into the rear cell of the
telescope. The screws are long enough to obstruct the movement of, and possibly chip the primary mirror.

Telescope Basics16
Attaching the Finder to the Bracket
With the bracket firmly attached to the telescope, you are ready to attach the finder to the bracket.
1. Thread the three nylon screws into the front ring of the finder bracket. Tighten the screws until the
nylon heads are flush with the inner diameter of the bracket ring. Do NOT thread them in
completely or they will interfere with the placement of the finder.
2. Slide the O-Ring over the back of the finder-it may need to be stretched a little.
3. Position the O-Ring on the main body of the finder so that it is toward the front (i.e., objective) end
of the finder.
4. Slide the end of the finder where the eyepiece mounts into the front of the bracket. Push it back
until the end of the finder, where the eyepiece attaches, is past the back ring of the bracket , but
NOT so far that the O-Ring is snug inside the back ring.
5. Slide the O-Ring toward the back(i.e., eyepiece end) of the finder.
6. Push the finder back until the O-Ring is snug inside the back ring of the finder bracket.
7. Hand tighten the three nylon-tipped thumbscrews until snug.
Figure 2-7

Telescope Basics 17
OPTIONAL ILLUMINATOR OPERATION
Installing the Battery
(only applies to 7x50 finder)
As mentioned previously, the reticle in the finder is used for polar alignment. To help you see the reticle at
night, there is an illuminator with a red Light Emitting Diode (LED). The illuminator comes with two
camera batteries (LR44). To install the batteries:
1. Remove the top of the illuminator housing by rotating it in the “off” direction.
2. Insert the batteries with the negative (-) end first.
3. Thread the top of the illuminator back on.
4. Turn the knurled knob on the end of the illuminator in the “ON” direction to make sure the
batteries were installed correctly. If the LED illuminates, turn the knurled knob in the “OFF”
direction to conserve power. If the LED does not illuminate, remove the cover and flip the
batteries 180°.
For replacement purposes, the correct batteries are Toshiba LR44 or equivalent.
Operating Information
• The brightness of the reticle can be varied by turning the “ON/OFF” knob on the end of the illuminator
housing. Once the knob clicks, the LED is on. To increase the brightness, continue turning the knob in
the “ON” direction.
• To insert the illuminator into the reticle housing, turn the thumbscrew on the reticle ring until it no
longer obstructs the inner diameter of the ring. Insert the LED end of the illuminator and tighten the
thumbscrew on the reticle ring to hold it in place.
• To focus the reticle, turn the top portion of the eyepiece (on the reticle housing) until sharp. The
direction may vary depending upon your eyesight.
• To focus the finder, loosen the knurled locking ring on the front of the finder and rotate the objective
lens housing until the image is sharp. Tighten the locking ring to ensure that the finder stays in focus.
The finder is preset for infinity focus.
The correct procedure for using the reticle is described in the section on “Polar Alignment.”

Telescope Basics18
INSTALLING THE VISUAL ACCESSORIES
Installing the oculars and other visual accessories is the same for both the Ultima 91/4and the 11. The only
difference is that the rear cell, for the Ultima 11, is 3.290 inches in diameter and requires a reducer plate.
The reducer plate adapts the rear cell to the Celestron two inch standard. The Ultima 11 comes with the
reducer plate installed.
The Visual Back
The visual back allows you to attach most visual accessories to the telescope. If you use an 1-1/4" star
diagonal or if you want to insert the eyepiece into the telescope without a diagonal, then the visual back
attaches to the standard 2 inch rear cell on the back of the telescope (see figure 2-8). To attach the visual
back:
1. Remove the protective cap from the back of your telescope. It is pressed onto the rear cell.
2. Place the slip ring on the visual back over the threads on the rear cell.
3. Tighten by rotating the slip ring clockwise until tight.
Once this is done, you are ready to attach other accessories such as eyepieces, and diagonal prisms. 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 is a prism
that diverts the light at a
right angle from the light
path of the telescope. For
astronomical observing, this
allows you to observe in
positions that are more
comfortable than if you were
to look straight through. To
attach the star diagonal:
1. Turn the
thumbscrew on the
visual back until its
tip no longer
extends into (i.e.,
obstructs) the inner
diameter of the
visual back.
Figure 2-8
2. Slide the chrome portion of the star diagonal into the visual back.
3. Tighten the thumbscrew on the visual back to hold the star diagonal in place.
If you wish to change the orientation of the star diagonal, loosen the thumbscrew on the visual back until the
diagonal rotates freely. Rotate the diagonal to the desired position and tighten the thumbscrew.

Telescope Basics 19
The Eyepieces
The eyepiece, or ocular, is the optical element
that magnifies the image focused by the
telescope. The eyepiece fits either into the
visual back directly or into the star diagonal. To
install an eyepiece:
1. Loosen the thumbscrew on the star
diagonal so that it does not obstruct the
inner diameter of the eyepiece end of
the diagonal.
2. Slide the chrome portion of the
eyepiece into the star diagonal.
3. Tighten the thumbscrew on the
diagonal to hold the eyepiece in place.
To remove the eyepiece, loosen the thumbscrew
on the star diagonal and slide the eyepiece out.
In addition to barrel diameter, eyepieces are also referred to in terms of their focal length. The focal length
of each eyepiece is printed on the eyepiece barrel. The longer the focal length (i.e., the larger the number),
the lower the eyepiece power and the shorter the focal length (i.e., the smaller the number), the higher the
magnification. Generally, you will use low-to-moderate power when viewing. For more information on
how to determine power, see the section on “Calculating Magnification.”
Barrel diameter is the diameter of the barrel that slides into the star diagonal. Standard barrel diameters are
.96”, 1.25”, and 2”. The Ultima 91/4and 11 come standard for use with 1.25” barrel eyepieces.
MOVING THE TELESCOPE IN R.A. AND DEC
Once set up, you will need to move your telescope to different objects. To make rough adjustments, loosen
the R.A. and DEC slow motion clamps and move the telescope in the desired direction (see figure 2-9). Do
not move the wedge and tripod, only the telescope optical tube. Once in place, lock the R.A. and DEC
clamps to hold the telescope in place.
For fine adjustments, use the R.A. and DEC slow motion knobs. If you are making an adjustment in
declination, simply turn the declination knob (see figure 2-11). The DEC clamp does not have to be
loosened. Once you have located the desired target, stop turning the DEC knob. If the DEC knob will not
turn, the DEC tangent arm has most likely reached the end of the threaded rod (see figure 2-11). To correct
this, turn the DEC knob in the opposite direction until the tangent arm is in the center of the fork tine (look
at the inside of the fork tine). Release the DEC clamp and re-center the object you were looking at.
Tighten the DEC clamp and the DEC slow motion knob will again allow fine adjustments.
Note that adjustments to the DEC axis indicate inaccurate polar alignment. To minimize adjustments to this
axis, accurate alignment should be done before observing (see the section on “Polar Alignment”).
Figure 2-9

Telescope Basics20
For fine adjustments in R.A., release the R.A. clamp until the R.A. knob rotates freely. Turn the R.A. knob
until the desired object is centered (see figure 2-12). Once centered, tighten the R.A. clamp. The clamp
must be sufficiently locked for the drive motor to engage and move the telescope.
Do not force the R.A. knob to turn when the R.A. clamp is fully engaged. This may strip the R.A. pinion.
In addition, do not force the fork mount to swivel when the r.a. clamp is fully engaged. This may damage
the drive base.
Figure 2-10