iOptron CEM120 User manual

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iOptron® CEM120 Center-Balanced Equatorial Mount
Instruction Manual
Product #7300, #7301 & #7302

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Read the Instruction BEFORE setting up and using the mount! Worm/gear system damage due
to improperly use will not be covered by warranty.
If you have any questions please contact us at [e-mail]
WARNING!
NEVER USE A TELESCOPE TO LOOK AT THE SUN WITHOUT A PROPER FILTER!
Looking at or near the Sun will cause instant and irreversible damage to your eye.
Children should always have adult supervision while using a telescope.

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Table of Contents
Table of Contents .................................................................................................................................................... 3
1. CEM120 Introduction ......................................................................................................................................... 6
2. CEM120 Terms ................................................................................................................................................... 7
2.1. Parts List ...................................................................................................................................................... 7
2.2. Identification of Parts ................................................................................................................................... 8
2.3. CEM120 Mount Basic Cable Connection.................................................................................................... 9
2.4. CEM120 Cable Management ....................................................................................................................... 9
2.5. Go2Nova® 8407+ Hand Controller ............................................................................................................ 12
2.5.1. Key Description .................................................................................................................................. 12
2.5.2. The LCD Screen ................................................................................................................................. 13
2.6. Check the Battery ....................................................................................................................................... 14
3. CEM120 Mount Assembly ............................................................................................................................... 15
4. Getting Started .................................................................................................................................................. 22
4.1. Setting the Mount and Performing Polar Alignment ................................................................................. 22
4.2. Manual Operation of the Mount ................................................................................................................ 22
4.3. Push-to Operation of the Mount ................................................................................................................ 22
4.4. The mount can now be used to observe astronomical objects using the HC. Use the arrow keys Initial
Star Alignment .................................................................................................................................................. 22
4.5. GOTO the Moon and Other Objects .......................................................................................................... 23
4.6. Star Identification Function ....................................................................................................................... 23
4.7. Power-Down Memorization....................................................................................................................... 23
4.8. Turning Off the Mount............................................................................................................................... 23
5. Complete Functions of Go2Nova® 8407+ Hand Controller ............................................................................. 24
5.1. Select and Slew .......................................................................................................................................... 24
5.1.1. Solar System ....................................................................................................................................... 24
5.1.2. Deep Sky Objects ................................................................................................................................ 24
5.1.3. Stars..................................................................................................................................................... 24
5.1.4. Comets ................................................................................................................................................ 24
5.1.5. Asteroids ............................................................................................................................................. 24
5.1.6. Constellations ...................................................................................................................................... 24
5.1.7. Custom Objects ................................................................................................................................... 24
5.1.8. Customer R.A. and DEC ..................................................................................................................... 25
5.2. Sync to Target ............................................................................................................................................ 25
5.3. Alignment .................................................................................................................................................. 25
5.3.1. Position of Polaris/SigmaOct .............................................................................................................. 25
5.3.2. One Star Alignment ............................................................................................................................ 25
5.3.3. Two Star Alignment ............................................................................................................................ 25
5.3.4. Three Star Alignment .......................................................................................................................... 26
5.3.5. Solar System Align ............................................................................................................................. 26
5.3.6. Polar Iterate Align ............................................................................................................................... 26
5.3.7. View Model Error ............................................................................................................................... 26
5.3.8. Clear Alignment Data ......................................................................................................................... 26
5.4. Settings ....................................................................................................................................................... 26
5.4.1. Set Time and Site ................................................................................................................................ 26
5.4.2. Beep Settings ...................................................................................................................................... 27
5.4.3. Display Settings .................................................................................................................................. 27
5.4.4. Set Guiding Rate ................................................................................................................................. 27

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5.4.5. Set Tracking Rate ................................................................................................................................ 28
5.4.6. Set Parking Position ............................................................................................................................ 28
5.4.7. Meridian Treatment ............................................................................................................................ 28
5.4.8. Set Altitude Limit ............................................................................................................................... 28
5.4.9. Enable CW Up Position ...................................................................................................................... 28
5.4.10. HC Heating Switch ........................................................................................................................... 29
5.4.11. Set RA Guiding ................................................................................................................................. 29
5.4.12. Network Options ............................................................................................................................... 29
5.4.13. Power LED Switch ........................................................................................................................... 29
5.4.14. Reset All Settings .............................................................................................................................. 29
5.4.15. Language ........................................................................................................................................... 29
5.5. Electric Focuser ......................................................................................................................................... 30
5.6. PEC Option ................................................................................................................................................ 30
5.6.1. PEC Playback...................................................................................................................................... 30
5.6.2. Record PEC ......................................................................................................................................... 30
5.6.3. PEC Data Integrity .............................................................................................................................. 30
5.7. Park Telescope ........................................................................................................................................... 30
5.8. Edit User Objects ....................................................................................................................................... 31
5.8.1. Enter a New Comet ............................................................................................................................. 31
5.8.2. Enter Other Objects or Observation List ............................................................................................ 31
5.9. Firmware Information ................................................................................................................................ 32
5.10. Zero Position ............................................................................................................................................ 32
5.10.1. Goto Zero Position ............................................................................................................................ 32
5.10.2. Set Zero Position ............................................................................................................................... 32
5.10.3. Search Zero Pos. ............................................................................................................................... 32
6. Maintenance and Servicing ............................................................................................................................... 33
6.1. Maintenance ............................................................................................................................................... 33
6.2. iOptron Customer Service .......................................................................................................................... 33
6.3. Product End of Life Disposal Instructions ................................................................................................. 33
6.4. Battery Replacement and Disposal Instructions ........................................................................................ 33
Appendix A. Technical Specifications ................................................................................................................. 34
Appendix B. Go2Nova® 8407+ HC MENU STRUCTURE ................................................................................. 35
Appendix C. Firmware Upgrade ........................................................................................................................... 38
Appendix D. Computer Control a CEM120 Mount.............................................................................................. 39
Appendix E. Go2Nova®Star List .......................................................................................................................... 40
IOPTRON TWO YEAR TELESCOPE, MOUNT, AND CONTROLLER WARRANTY ................................. 46
Ver. 1.0 2018.3
iOptron reserves the rights to revise this instruction without notice. Actual color/contents/design/function may differ from those described in this
instruction manual.

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Instruction for CEM120 Gear Switch and Axle Locking Knob
Both RA and DEC have the same Gear Switch and Axle Locking Knob, the operations are the same.
Gear Switch Axle Locking Knob
As an example, here are the positions for the Gear Switch and Axle Locking Knob for RA axis:
A: When transferring or installing the mount, lock the Axle Locking Knob and disengage the Gear
Switch . So the RA won’t swing and there is no force applied onto the worm/ring gear.
B: During mount balancing process, pull and turn the Axle Locking Knob to release it and leave the
Gear Switch at disengaged position . Now the mount will swing freely in RA direction.
C: During normal operation of the mount, i.e., GOTO and tracking, turn the Gear Switch to locking
position to engage the worm/ring gear while leave the Axle Locking Knob released 。
A. During transferring and
installing…
B. During balancing…
C. During operating…
ONLY set the Gear Switch at locking position to engage the worm/ring gear during goto, slew or
tracking.
ALWAYS lock the Axle Locking Knob during transferring and installing.
DO NOT lock both Gear Switch and Axle Locking Knob at the same time.

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1. CEM120 Introduction
Welcome to a new type of equatorial mount – the iOptron® Center-Balanced Equatorial Mount,
or CEM! It offers the benefits of our revolutionary “center balance” design: stability, accuracy, and
smooth mechanical operation, while capable of carrying a payload up to 115 lbs (52 kg). The “center
balance” design’s natural stability is due to its focusing the mount along with payloads weight directly
over the center of the pier or tripod.
The CEM120's performance is demonstrated by its low periodic tracking error: <±3.5 arc
seconds for CEM120 and <0.15 arcsec RMS for CEM120EC/CEM120EC2. Along with the stability
aspect, the CEM120 features an advanced cable management system consisting of more ports in more
locations preventing tangle ups and reducing the chance of fractured cables. It also adds some new
features to the CEM family like Wi-Fi and LAN for remote operation and easy to use, reliable clutches
on both axes.
The CEM120 family has three versions: CEM120 standard version (#7300), CEM120EC
(#7301) with high precision optical encoder on RA axis, and CEM120EC2 (#7302) with high precision
optical encoders on both RA and DEC axes.
The CEM12 mount is equipped with the most advanced GOTONOVA® GOTO technology,
making it one of the most powerful and accurate GOTO mounts available. TheGo2Nova® 8407+ hand
controller has a database of over 212,000 objects making it easy to locate even the faintest celestial
objects.
Features:
 A new design, center-balanced equatorial mount (CEM) for maximum payload with natural
stability
 Observatory astrophotography mount ideal for both visual and Astro-photographers
 Payload of 115 lbs (52 kg) with the mount weight of 57 lbs (26 kg)
 Easy to use and reliable gear clutches
 Precision altitude and azimuth adjustment.
 Precision stepper motor with 0.07 arcsec accuracy for precise GOTO and accurate tracking
 Polar alignment routine for those who can't see the Pole Star
 Go2Nova® 8407 V2 controller with Advanced GOTONOVA® GOTO Technology with built in
heater
 High precision tracking with low periodic error: PE<±3.5 arcsec for #7300, or PE <0.15 arcsec
RMS for #7301/#7302
 Permanent periodic error correction (PPEC) (#7300) or Real-time periodic error correction
(RPEC) (#7301/#7302)
 Push-to operation for CEM120EC and CEM120EC2
 Built-in 32-channel Global Positioning System (GPS)
 Built-in WiFi and LAN for remote operation
 Integrated ST-4 autoguiding port
 AutoZeroTM technology for mount remote operation
 Power-down memorization of GOTO and tracking position
 Advanced cable management system with more choices
 Spring loaded, individual adjustable Losmandy saddle

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2. CEM120 Terms
2.1. Parts List1
SHIPPING CONTENTS
Your new CEM120 mount comes in two shipping boxes. One box contains either a CEM120
(#7300), CEM120EC (#7301) or CEM120EC2 (#7302) mount head, hand controller, and accessories.
The other box contains a 22lb (10kg) counterweight and counterweight shaft. The contents are:
 1X iOptron
® CEM120 telescope mount (#7300, with silver adjustment knobs), iOptron®
CEM120EC mount (#7301, high precision model with red adjustment knobs), or iOptron®
CEM120EC2 mount (#7302,dual high precision model with red adjustment knobs)
 1X Go2Nova® 8407 V2 Hand Controller
 1X 22lb (10 kg) counterweight
 1X Stainless steel counterweight shaft
 1X 12V/5A AC/DC adapter (100V-240V, with 2.5mmX5.5mm plug)
 1X Hand Controller Cable (6P6C RJ11 to RJ11, straight wired)
 1X Serial cable (RS232 to RJ9)
 4X Base mounting screws
 1X external GPS antenna
 1X Wi-Fi external antenna
OPTIONAL PARTS
 Electronic polar scope adapter (#3337-120)
 Pier top mounting plate
 USB to RS232 Converter with FTDI chipset (#8435)
ONLINE RESOURCES (click on the “Support” menu at www.iOptron.com)
 Quick Start Guide
 Instructional manual
 Tips for set up
 Hand controller and mount firmware upgrades (check online for latest version)
 iOptron ASCOM driver
 Reviews and feedback from other customers
 Accessories
1 US market only. Actual contents may vary.

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2.2. Identification of Parts
Figure 1.CEM120 mount assembly
DovetailSaddle
DovetailLockingKnob
DECAxleLockingKnob
DECGearSwitch
RAAxis
CWShaftMountingHouse
CWShaft
CWShaftSafetyLock
Counterweight
MountBase
AZIAdjustmentKnob
BaseMountingScrew
RAAxleLockingKnob
RAGearSwitch
ALTAdjustmentKnob
ALTLockingClamp
Cablemanagement
OutputPanel
Cablemanagement
InputPanel
MountBasicPorts

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2.3. CEM120 Mount Basic Cable Connection
The basic cable connection ports of a CEM120 mount are all located on the mount base, as
shown in Figure 2.
Figure 2. Ports on a CEM120 mount base
 DC 12V 5A: DC power socket to power the mount (2.5mmX5.5mm, 5525)
 ON/OFF: Power Switch
 HBX (Hand Box): For connecting to an 8407 Hand Controller
 RS232: Serial port for mount computer control and firmware upgrade
 USB: USB port for mount computer control
 LAN: network connection for remote control
 WiFi: Mini coaxial cable connector for WiFi antenna
 GPS: Mini coaxial cable connector for GPS external antenna
2.4. CEM120 Cable Management
The CEM120 mount has a pre-wired Cable Management System that allows the user to connect
their accessories and imaging equipment without cables tangling or snagging when the mount is
slewing or tracking. The Cable Management Outputs are located at the back of the dovetail saddle, as
shown below.
Figure 3. Connects at the end f the dovetail saddle
Figure 4. GUIDE port wiring
At the end of the dovetail saddle, there are
 USB 2.0 x 4: 4 USB 2.0 ports with standard type A connectors for connecting accessories
(un powered). They were connected to the USB2.0 input on Input Panel.
 GUIDE: port for autoguiding with ST-4 cable. The wiring is shown in Figure 4.
 AUX (OUT): A DIN-422 port for high power or other connection purpose. It is connected to
the AUX (IN) port on Input Panel.

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Figure 5. AUX port DIN-422 socket
 iPORT: for iOptron compatible accessories, such as electrical focuser.
 USB 3.0: Powered USB 3.0 port. It is connected to the USB3.0 input on the Input Panel.
 5521 5V1A socket: a 2.1mmX5.5mm 5V DC power output for accessories. Maximum 1A,
center positive. This is provided by mount DC 12V power.
Figure 6. Power output sockets
On the side of the dovetail saddle, there are 4 power output sockets:
 5521 12V1A socket X2: There are two 12V1A DC output sockets on the right end side of the
dovetail saddle, with 2.1mmX5.5mm, center positive sockets. They are provided by mount
DC 12V power.
 On the left end side of the dovetail saddle, there are one 5525 (2.5mmx5.5mm) and one
5521 (2.1mmX5.5mm) DC output sockets for your accessories. The maximum specified
current output is 5A. They are connected to the DC IN 10 port on the Input Panel. The
voltage is determined by the input voltage, such as V, 12V or 24V.
Figure 7. Cable Management System Input Panel

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The ports on the Cable Management Panel are connected to the Input Panel located at the end
of the mount RA axis, as shown in Figure 7:
 1X DC IN 10A power input (2.5mmX5.5mm, 10A max.)
 1X USB 2.0 port with a standard type B connector
 1X USB 3.0 port
 1X AUX IN port (for data or extra power input)
 iPolarScope port for electronic polar scope connection

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2.5. Go2Nova®8407+ Hand Controller
Figure 8. Go2Nova® 8407+ hand controller
The Go2Nova® 8407+ hand controller (HC) shown in Figure 8 is the standard controller used on
the CEM120 mount. It has an integrated heater that ensures the LCD display will work at the
temperature as low as -20ºC(-4ºF). It has a large LCD screen, function, direction, and number keys on
the front; a red LED reading light on the back; and a HBX (6-pin) and a serial port (4-pin) at the bottom.
2.5.1. Key Description
 MENU Key: Press “MENU” to enter the Main Menu.
 BACK Key: Move back to the previous screen, or end/cancel current operation, such as
slewing.
 ENTER Key: Confirm an input, go to the next menu, select a choice, or slew the telescope
to a selected object.
 Arrow (▲▼◄►) Keys: The arrow keys are used to control the movement of DEC and R.A.
axes. Press and hold ▲(DEC+),▼(DEC-) buttons to move a telescope along the DEC
direction, ◄(R.A.+), ►(R.A.-) to move a telescope along the R.A. direction. They are also
used to browse the menu or move the cursor while in the menu. Press and holding an arrow
key for a fast scrolling.
 Number Keys: Input numerical values. Also used to adjust speeds (1: 1X; 2: 2X; 3: 8X; 4:
16X; 5: 64X; 6: 128X; 7: 256X; 8: 512X; 9: MAX)
 Light Key(☼): Turns on/off the red LED reading light on the back of the controller.
 Help (?) Key: Identify and display bright stars or objects that the telescope is pointing to.
 STOP/0 Key: Stop the mount during GOTO. Also toggling between starting and stopping
tracking.
 HBX (Handbox) port: connect the HC to a mount using a 6P6C RJ11 cable.
HBX
Port
Serial
Port
R.A.+ R.A.-
DEC-
DEC+

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 Serial port: connect the HC to a computer via a RS232 to 4P4C RJ9 cable. The pin-out of
the serial port is shown in Figure 9.
Figure 9. Serial port pin-out on an 8407+ hand controller
2.5.2. The LCD Screen
The 8407+ HC has a large 8-line, 21-character per line, LCD screen which displays information
on the status of the mount as shown in Figure 10.The user interface is simple and easy to operate.
Figure 10. 8407+ HC LCD Information Screen
1. Target Name/Mount Position: displays the name of the target that telescope is currently pointed to
or the current mount position.
 Zero Position: The reference position for GOTO. The mount can move to Zero Position
using “Goto Zero Position” or “Search Zero Position” command;
 User Position: The mount is pointed to a user defined position, which could be a particular
celestial object or simply a position determined by pressing an arrow key;
 An object name, such as “Mercury” or “Andromeda Galaxy”: Name of the star or celestial
object that the mount is currently slewing to or tracking.
2. Target R.A.: Right Ascension (R.A.) of the target object.
3. Target Declination: Declination (DEC) of the target object.
4. Right Ascension: Current R.A. of the telescope.
5. Declination: Current DEC of the telescope.
6. Altitude: Altitude of the telescope (degrees vertical from the local horizon - zenith is 90º).
7. Azimuth: Azimuth of the telescope (north is 0º, east is 90º, south is 180º, and west is 270º).
8. Local Date and Time: displays the local time in a format of YY-MM-DD HH:MM:SS.
9. Mount Status: Displays the current operational status of the mount.
 Stop: mount is not moving;

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 Slew: mount is moving with an arrow key is pressed or a GOTO command, such as “Select
and Slew” or “Goto Zero Position”;
 Tracking: mount is at a tracking status.
10. GPS status: When the power is turned on, the initial GPS status will be “GPS ON”, which means
that the mount is connected to its GPS receiver and is seeking a satellite signal. When the GPS
receiver finds the satellites and receives the GPS signal the status will change to “GPS OK”.
11. PEC status: Display of “PEC” here Indicates the Periodic Error Correction playback is turned on.
Default is off.
12. Tracking speed: Displays the current tracking rate of the mount.
 SDRL: mount is tracking at sidereal speed;
 Solar: mount is tracking at solar speed;
 Lunar: mount is tracking at lunar speed;
 King: mount is tracking at king speed;
 CSTM: mount is tracking at a custom, user-defined speed.
13. Slew speed: The mount has 9 slew speeds: 1X, 2X, 8X, 16X, 64X, 128X, 256X, 512X,
MAX(4°/sec).
14. Operation Mode: EQ indicates that the mount is operating in an equatorial mode.
2.6. Check the Battery
The hand controller has a real time clock (RTC) which should display the correct time every time
the mount is turned on. If the time is incorrect, please check the battery inside the hand
controller and replace it if needed. The battery is a 3V, CR1220 button battery.

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3. CEM120 Mount Assembly
STEP 1. Attach the Mount
Make sure that the RA axle is at the locking position (please refer to the charts on page 5).
Remove the mount from the package. Put it onto a pier/tripod top and secure it with four included Base
Mounting Screws.
(a) (b)
Figure 11. (a) Attach the mount, and (b) mount base dimension
Because of the total weight of the mount, counterweight and payload, we recommend use your
own pier for the mount. The base dimension is shown in

STEP 2. Install the Counterweight (CW) Shaft
Hold the mount head with one hand. Pull the RA Axle Locking Knob outward to disengage the
lock. Slowly rotate the mount RA 90 degree to level position. Release the RA Axle Locking Knob to lock
the RA axis again.
Figure 12. Install CW shaft

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Remove the CW shaft from the package and threaded it onto the CW shaft mounting house. DO
NOT release the RA Axle Lock before the CW shaft is fully threaded in. The CW shaft is designed to
balance the mount head weight.
DO NOT rock the counterweight shaft rigorously. It may damage the worm system.
STEP 3. Adjust Altitude
This step requires you to know the latitude of your current location. This can be found from your
8407+ hand controller after the embedded GPS receives the signal from the satellites. It can also be
easily found on the Internet, using a GPS satellite-navigation system, or a GPS capable cell phone.
You will have to change this latitude setting every time you significantly change your night sky viewing
location. Note that this setting directly affects the mount’s GOTO accuracy.
Figure 13. Setting the latitude
Figure 14. Latitude Adjustment Knob
Slightly loosen the Altitude Locking Clamps about a quarter (1/4) turn with a 5mm Allen wrench,
on both side of the mount. Turn the Altitude Adjustment Knob until the arrow points to your current
latitude on the Latitude Scale, as shown in Figure 13. Tighten the Altitude Locking Clamps when done.
The altitude adjustment employs worm gear system and can be adjusted precisely when turn in
one direction. The fine adjustment is 0.5 arcmin.
The mount latitude adjustment range is from 0° to 68°. For those low latitude places between
0° to 10°, special low latitude CWs (#7326LL) are needed. Please specify when order.
STEP 4. Install the Counterweight(s) and Telescope
Before installing the Counterweight(s), make sure that mount is at Zero Position, i.e., CW shaft
is pointing to ground. Both R.A. and DEC Axle Locking Knobs are at the locking position (refer to
Illustration A on page 5).
Remove the CW Safety Cap at the end of CW Shaft. Guide the CW over the shaft. Tighten the
CW Locking Screw to hold the CW in place. Place the Safety Cap back onto the shaft.
WARNING: The mount should always be kept in the zero position while it is being loaded
with CWs and payload.
Altitudelocking
clamp
Altitude
Adjustmentknob

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Figure 15. Loading counterweight
You may need more CWs for heavier payload, or smaller size CW for lighter scope.
The CEM120 has a Losmandy-D dovetail saddle plate, as shown in Figure 16. Release the
dovetal saddle locking knobs and slide the telescope dovatal plate into the saddle. Tighten the saddle
locking knob.
Figure 16. CEM120 dovetail saddle plate

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STEP 5. Balance the Payload
After attaching the scope and accessories, the mount head assembly must be balanced in both
R.A. and DEC axes to ensure minimum stresses on the mount driving mechanism.
CAUTION: The telescope may swing freely when the R.A. or DEC during the balancing process.
Always hold on to the mount and/or telescope assembly before releasing the Axle Locking
Knob and/or Gear Switches to prevent it from swinging, which can cause personal injury and/or
equipment damage.
With the corresponding Gear Switch disengaged, balance in DEC axis by moving the scope with
accessories back and forth in the mount saddle. Balance the assembly in R.A. axis by moving CW
along its shaft.
Only balance one axis at a time and start with the DEC axis first. Double check the mount to
make sure both the RA and DEC axes are balanced.
Return the mount to the Zero Position after balancing; i.e., the CW shaft points to ground, and
the telescope tip is at its highest position.
STEP 6. Connect Cables
Plug in a 12V DC power supply to the DC12V POWER socket; connect the Go2Nova® 8407
Hand Controller to the HBX port on the mount side panel; and install Wi-Fi antenna (right angle one)
and GPS antenna, as shown in .
STEP 7. Setup Hand Controller
The CEM120 mount is equipped with a GPS receiver which will receive the UTC time, longitude
and latitude information for your current location from satellites after a link is established. However,
there are still some parameters which need to be entered to reflect your location, such as time zone
information and whether daylight saving time is currently in effect. This information will be stored in the
mount until they need be updated.
The GPS with an external antenna should make the mount to connect the satellites in a few
minutes. If the GPS module has difficulty receiving the satellite signal, you may manually enter the
information.
To set up the controller, press MENU =>“Settings”:
Press ENTER and select “Set Time & Site”
Select and Slew
Sync. to Target
Alignment
Settings
Electric Focuser
PEC Options
Park Telescope
Edit User Ob
j
ects

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Press ENTER. A time and site information screen will be displayed:
Set Local Time
The time will be updated automatically when the GPS receiver has established its link with the
GPS satellites. In the event that the GPS module is unable to establish a link to the satellites, local time
can be entered manually. Use the ◄ or ► key to move the cursor _ and use the number keys to
change the numbers. Use the ▲ or ▼ button to toggle between “Y” and “N” for Daylight Saving Time,
or “+” and “-“ for UTC (Coordinated Universal Time) setting. Hold the arrow key to fast forward or
rewind the cursor.
In order to make the Hand Controller reflect your correct local time, time zone information has
to be entered. Press the ◄ or ► key, move the cursor to the third line “UTC -300 Minute(s)” to set the
time zone information (add or subtract 60 minutes per time zone). For example:
 Boston is “UTC -300 minutes”
 Los Angeles is “UTC -480 minutes”
 Rome is “UTC +60 minutes”
 Beijing is “UTC +480 minutes”
 Sydney is “UTC +600 minutes”
All the time zones in North America are “UTC –“, as shown in the following table, so ensure the
display shows “UTC -” instead of “UTC +” if in North or South America.
Time Zone Hawaii Alaska Pacific Mountain Central Eastern
Hour behind UT -10 -9 -8 -7 -6 -5
Enter UTC -600 -540 -480 -420 -360 -300
To adjust minutes, move the cursor to each digit and use the number keys to input the number
directly. Use ▲ or ▼ key to toggle between “+” and “-”. When the time one information entered is
correct, press ENTER and go back to the previous screen. Note that fractional time zones can be
entered.
Do not manually add or subtract an hour from displayed time to reflect Daylight Saving Time
(DST). Only select “Y” after DST begins.
For other parts of the world you can find your “time zone” information from internet.
Daylight Saving Time Y
UTC -300 Minute(s)
2014-03-09 10:19:18
Longitude:W071°08’50”
Latitude: N42°30’32”
Northern Hemisphere
Set Time and Site
Beep Settings
Display Settings
Set Guiding Rates
Set Tracking Rate
Set Parking Position
Meridian Treatment
Set Altitude Limit

20
Set Observation Site Coordinates
The third and fourth lines display the longitude and latitude coordinates respectively. The
longitude and latitude coordinates will be automatically updated when the GPS picks up a satellite
signal. “W/E” means Western/Eastern Hemisphere; “N/S” means Northern/Southern Hemisphere; “d”
means degree; “m” means minute; and “s” means second.
If, for any reason, your GPS does not pick up the satellite signal, you can manually enter your
longitude and latitude coordinates. Press the ◄ or ► key to move the cursor, use the ▲ or ▼ key to
toggle between “W” and “E”, and “N” and “S”, and use the number keys to change the numbers. It is
always a good idea to do your homework and get longitude and latitude coordinates before traveling to
a new observation site.
The site coordinates information can be found from your smart phone, GPS receiver or via the
internet. Site information in decimal format can be converted into d:m:s format by multiplying the
decimal numbers by 60. For example, N47.53 can be changed to N47º31'48”: 47.53º = 47º +0.53º,
0.53º=0.53x60'=31.8', 0.8'=0.8x60"=48". Therefore, 47.53º=47º31'48" or 47d31m48s.
Select N/S Hemisphere
The Northern/Southern Hemisphere will be selected automatically when the latitude is set,
unless the latitude is near the equator. When the latitude is between -10° ~ +10°, set it to Northern
Hemisphere if the polar axis is pointing to North, or Southern Hemisphere if the polar axis is pointing to
South.
STEP 8. Polar Alignment
In order for an equatorial mount to track properly, it has to be accurately polar aligned. A
CEM120 mount does not come with an optical polar scope. There are a few ways to perform the polar
alignment.
Polar Alignment Software
There are quite a few alignment software available or polar alignment, such as TPoint with The
Sky software, PemPro, or Alignmaster
Optional Electronic Polar Scope
A CEM120 has a built-in USB connection (iPolarScope port) for an electronic polar scope. With
a proper adapter, an electronic polar scope, such as PoleMaster can be installed onto the mount and
ready to use.
Figure 17. CEM120 with an installed electronic polar scope