iOptron GEM45EC User manual

iOptron®GEM45 German Equatorial Mount
Instruction Manual
Product GEM45 (#7603A), GEM45EC (#7603ECA) and GEM45G (#7603AG)

Please read the included GEM45 Quick Setup Guide (QSG) BEFORE taking the mount out of the
case!
This product is a precision instrument. Please read the included QSG before assembling the
mount. Please read the entire Instruction Manual before operating the mount.
You must hold the mount firmly when disengaging the gear switches. Otherwise personal injury
and/or equipment damage may occur. Any worm system damage due to improper operation will
not be covered by iOptron’s limited warranty.
If you have any questions please contact us at [email protected]m
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.

Table of Contents
Table of Contents ...............................................................................................................................................3
1. GEM45 Introduction ......................................................................................................................................5
2. GEM45 Overview ..........................................................................................................................................6
2.1. Parts List..................................................................................................................................................6
2.2. Identification of Parts ..............................................................................................................................7
2.3. GEM45 Mount Basic Cable Connection.................................................................................................7
2.3.1. Power Panel on Rear of RA axis......................................................................................................7
2.3.2. Ports on Main Control Board ...........................................................................................................8
2.3.3. Ports on Dovetail Saddle..................................................................................................................8
2.4. Go2Nova®8407+ Hand Controller.......................................................................................................10
2.4.1. Key Description..............................................................................................................................10
2.4.2. The LCD Screen.............................................................................................................................11
2.4.3. Check the Hand Controller Battery................................................................................................12
2.5. Bench Testing the Mount ......................................................................................................................12
3. GEM45 Mount Assembly.............................................................................................................................13
3.1. GEM45 Mount Assembly......................................................................................................................13
4. Getting Started..............................................................................................................................................21
4.1. Setting the Mount and Performing Polar Alignment.............................................................................21
4.2. Manual Operation of the Mount............................................................................................................21
4.3. One Star Alignment...............................................................................................................................21
4.4. GOTO the Moon and Other Objects .....................................................................................................21
4.5. Star Identification Function...................................................................................................................21
4.6. Power-Down Memorization..................................................................................................................22
4.7. Turning Off the Mount..........................................................................................................................22
4.8. Putting the Mount Back into the Carrying Case....................................................................................22
5. Complete Functions of Go2Nova®8407+ Hand Controller ........................................................................23
5.1. Select and Slew......................................................................................................................................23
5.1.1. Solar System...................................................................................................................................23
5.1.2. Deep Sky Objects...........................................................................................................................23
5.1.3. Stars................................................................................................................................................23
5.1.4. Comets............................................................................................................................................23
5.1.5. Asteroids.........................................................................................................................................23
5.1.6. Constellations.................................................................................................................................23
5.1.7. Custom Objects ..............................................................................................................................23
5.1.8. Custom R.A. and DEC ...................................................................................................................24
5.2. Sync to Target........................................................................................................................................24
5.3. Alignment..............................................................................................................................................24
5.3.1. Position of Polaris/SigmaOct .........................................................................................................24
5.3.2. One Star Alignment........................................................................................................................24
5.3.3. Two Star Alignment.......................................................................................................................24
5.3.4. Three Star Alignment .....................................................................................................................25
5.3.5. Solar System Align.........................................................................................................................25
5.3.6. Polar Iterate Align ..........................................................................................................................25
5.3.7. View Model Error...........................................................................................................................25
5.3.8. Clear Alignment Data.....................................................................................................................25
5.4. Settings ..................................................................................................................................................25
5.4.1. Set Time and Site............................................................................................................................25
5.4.2. Beep Settings..................................................................................................................................26

5.4.3. Display Settings..............................................................................................................................26
5.4.4. Set Guiding Rate.............................................................................................................................26
5.4.5. Set Tracking Rate...........................................................................................................................27
5.4.6. Set Parking Position .......................................................................................................................27
5.4.7. Meridian Treatment........................................................................................................................27
5.4.8. Set Altitude Limit...........................................................................................................................27
5.4.9. Polar Scope Bright..........................................................................................................................27
5.4.10. HC Heating Switch.......................................................................................................................27
5.4.11. Set RA Guiding ............................................................................................................................28
5.4.12. Language ......................................................................................................................................28
5.5. Electric Focuser.....................................................................................................................................28
5.6. PEC Option............................................................................................................................................28
5.6.1. PEC Playback.................................................................................................................................28
5.6.2. Record PEC....................................................................................................................................28
5.6.3. PEC Data Integrity .........................................................................................................................28
5.7. Park Telescope.......................................................................................................................................29
5.8. Edit User Objects...................................................................................................................................29
5.8.1. Enter a New Comet ........................................................................................................................29
5.8.2. Enter Other Objects or Observation List........................................................................................29
5.9. Firmware Information ...........................................................................................................................30
5.10. Zero Position .......................................................................................................................................30
5.10.1. Goto Zero Position .......................................................................................................................30
5.10.2. Set Zero Position ..........................................................................................................................30
5.10.3. Search Zero Pos............................................................................................................................30
6. Maintenance and Servicing ..........................................................................................................................31
6.1. Maintenance ..........................................................................................................................................31
6.2. iOptron Customer Service.....................................................................................................................31
6.3. Product End of Life Disposal Instructions ............................................................................................31
6.4. Battery Replacement and Disposal Instructions....................................................................................31
Appendix A. Technical Specifications.............................................................................................................32
Appendix B. Go2Nova®8407+ HC MENU STRUCTURE............................................................................33
Appendix C. Go2Nova®Star List ....................................................................................................................36
Appendix D. Gear Meshing Adjustment..........................................................................................................45
Appendix E. Polar Alignment using iPolar Electronic PolarScope .................................................................47
Appendix F. iGuider for GEM45G ..................................................................................................................48
Appendix G. Firmware Upgrade......................................................................................................................53
Appendix H. Computer Control a GEM45 Mount...........................................................................................54
IOPTRON TWO YEAR TELESCOPE, MOUNT, AND CONTROLLER WARRANTY............................55
Ver. 2.1 2021.3
iOptron reserves the rights to revise this instruction without notice. Actual color/contents/design/function may differ from those described in this
instruction manual.

1. GEM45 Introduction
Innovative ideas applied to a time tested design, the iOptron®GEM45 next generation German equatorial
mounts. A sharp looking CNC body is the first indicator the GEM45 is a top quality mount in both form and
function.
Utilizing experiences gained during development of our CEM series, we were able to remove unnecessary
bulk giving the GEM45 an incredible 2.5 payload to mount weight ratio. This compact 17.4lbs mount can
precisely GOTO an object and track with up to 45lbs of gear onboard.
With its integrated electronic polar scope (iPolarTM), polar alignment is a snap, even when the pole star is
obscured. Large levers on the quick-lock drive engagement system make it easy to snap its drive gears into
place even when wearing gloves. There is little chance of your cables getting snagged with the GEM45's
internal advanced cable management system.
Make way for an innovative mount! The GEM45G mount has a built-in iGuiderTM guiding camera. The mount
has a 6” dual saddle that accommodates Losmandy and Vixen-style dovetail plates. GEM45 mounts utilize
reliable stepper motor drive systems with our low power consumption technology. Our new LiteRoc 1.75"
tripod delivers rock solid stability in a lighter, more compact package. A 212,000+ object library with star
identification, GPS, Wi-Fi (requires optional iStarFi adapter) are a few of the desirable features standard on
a GEM45 mount.
Features:
German equatorial mount with innovative features
Idea for both visual observation and astrophotography
Maximum payload of 45 lbs (20 kg) with the mount weight of only 17.4 lbs (7.9 kg)
Easy to use quick-lock gear clutches
Integrated iPolarTM electronic polar finder
Built-in iGuiderTM guiding camera for GEM45G
Low periodic error: <±7 arc seconds for GEM45 and GEM45G, < 0.25 arcsec RMS for GEM45EC
Permanent periodic error correction (PPEC) or Real-time periodic error correction (for GEM45EC)
Precision stepper motor for precise GOTO and accurate tracking
Go2Nova®8407+ controller with Advanced GOTONOVA®GOTO Technology and built-in heater
Integrated ST-4 autoguiding port
32-channel Global Positioning System (GPS)
USB communication port
Cable management system
All metal, CNC machined with red/black anodized
Optional WiFi module (iStarFi, #7434) for mount control via SmartPhone/Tablet/Computer
All new LiteRoc 1.75" tripod with improved stability and leg locks

2. GEM45 Overview
2.1. Parts List1
SHIPPING CONTENTS
Your new GEM45 mount comes in three shipping boxes. Box 1 contains either a GEM45 (#7620A),
a GEM45G (#7620AG) or GEM45EC (#7620ECA) mount head, hand controller, counterweight shaft, and
accessories. Box 2 contains the LiteRoc tripod (#7623). Box 3 is a 11lbs (5kg) counterweight (#8027).
The contents are:
iOptron®GEM45 telescope mount
oGEM45 with iPolarTM electronic Polar Scope (#7620A);
oGEM45EC with iPolar and High Precision Optical Encoder (#7620ECA); or
oGEM45G with iPolar and iGuiderTM guiding system (#7620AG)
Go2Nova®8407+ Hand Controller
One 11lbs (5 kg) counterweight (#8027)
Stainless steel counterweight shaft
Internal iPolar electronic polar scope
Built-in iGuider autoguiding system on dovetail saddle (GEM45G only)
GEM45 GPS module
AC adapter (100V-240V)
2X coiled control Cable (6P6C RJ11 to RJ11, straight wired)
USB cable
Aluminum carrying case (for GEM45EC & GEM45G)
LiteRoc 1.75” tripod and accessory tray
Quick Start Guide
OPTIONAL PARTS
Tri-Pier (#8034)
iStarFi wireless adapter (#7434)
Serial cable for 8407 hand controller firmware upgrade (#8412)
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
1US market only. Actual contents, design, color and function may vary.

2.2. Identification of Parts
Figure 1.GEM45 mount assembly (GEM45G Shown)
2.3. GEM45 Mount Basic Cable Connection
2.3.1. Power Panel on Rear of RA axis
Figure 2. GEM45 Power Panel on Rear of RA axis
POWER (I/O): Power Switch
DC 12V 5A: DC power socket to power the mount (2.5mmX5.5mm, center positive)
USB2.0: USB input port to connect to iPolar, iGuider, USB 2.0 Port on dovetail saddle, as well as
mount computer control and firmware upgrade.

2.3.2. Ports on Main Control Board
Figure 3. Ports on a GEM45 main board
HBX (Hand Box): For connecting to an 8407 Hand Controller
iPORT: Auxiliary port for connecting to other iOptron accessories, such as a GPS receiver, an
iStarFi WiFi adapter, an electronic focuser or for observatory dome control. DO NOT plug ST-4
guiding camera cable into this port, It will damage the guide camera electronics.
2.3.3. Ports on Dovetail Saddle
On the back of the dovetail saddle, there are one USB2.0 port and two DC 12V outputs.
Figure 4.Port on back of the dovetail saddle (a GEM45G shown)
1X USB 2.0 ports with standard type A connectors for connecting accessory;
2X DC12V power outlet (2.1mmX5.5mm, center positive, max. current 3A) for powering
accessories such as CCD cameras, filter wheels, or electric focusers;
The ST-4 guiding port is located in front of the dovetail saddle.
Figure 5.Port on front of the dovetail saddle
ST-4: ST-4 compatible autoguiding port. The wiring is shown in Error! Reference source not
ound.

Figure 6. ST-4 Compatible Guiding Port Wiring

2.4. Go2Nova®8407+ Hand Controller
The Go2Nova®8407+ hand controller (HC) shown in Figure 7 is the standard controller used on the GEM45
mount. It has an integrated heater that ensures the LCD display will work at the temperature as low as -
10ºC. 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 RS232 serial port (4-pin) at the bottom.
The GEM45 mount can be operated without the hand controller attached if it is controlled via a
SmartPhone/Tablet/Computer.
Figure 7. Go2Nova®8407+ hand controller
2.4.1. 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
Port
Serial
Port
R.A.+
R.A.-
DEC-
DEC+

HBX (Handbox) port: connect the HC to the GEM45 mount using a 6P6C RJ11 cable.
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 8.
Figure 8. Serial port pin-out on an 8407+ hand controller
2.4.2. 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 9.The user interface is simple and easy to operate.
Figure 9. 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;
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 (~4º/sec).
14. Operation Mode: EQ indicates that the mount is operating in an equatorial mode.
2.4.3. Check the Hand Controller 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 HC can’t keep the date and time, the battery is low and needs be replaced. Please open
the back cover of the HC and replacement is straight forward.
2.5. Bench Testing the Mount
The counterweight shaft is designed to counter balance the mount’s own weight. It is recommended that the
CW shaft is installed when testing the mount’s function. Slewing the mount without the CW shaft installed is
not recommended.
NEVER operate the mount with only the counterweight or OTA on it. It may damage the precision
engineering of the mount drive system.

3. GEM45 Mount Assembly
3.1. GEM45 Mount Assembly
NOTE: The GEM45 mount is a precision astronomical instrument. It is highly recommended that you
read this entire manual and become familiar with the nomenclature and function of all components
before starting assembly.
WARNING: DO NOT rock the counterweight shaft rigorously. This may damage the
worm/drive gear system and such damage will not be covered by warranty.
STEP 1. Remove the mount head from package
The mount head is shipped with the R.A. Gear Switch unlocked to protect the worm/gear system. Turn the
Gear Switch 90° to lock the R.A. gear system before removing it from the box.
Figure 10. Mount in a hard case
STEP 2. Set up tripod
The tripod top is 120 mm in diameter with 2x M6 holes 103 mm apart for mounting. Two additional M6 holes
are for the Alignment Peg (the one on top of a leg is for high latitude use; the other one between two legs is
for low latitudes). Thread the Alignment Peg into the correct M6 hole. Insert the Accessory Tray through
the center rod and secure the setup by tightening Locking Knob from underneath.
Figure 11. Tripod top

STEP 3. Attach the mount
Retract the 2x Azimuth (Azi) Adjustment Screws from both sides to leave ample space for the alignment
peg to fit in between the 2 Azi Adjustment Screws. Remove the 2x Azi Locking Screws, with washers, from
the mount base. Secure the mount head by tightening the Azi Locking Screws into the M6 holes on the
tripod. An Allen wrench is included for convenience.
Figure 12. Attach the mount
Level the mount by adjusting the tripod legs. Use the build-in Bubble Level Indicator or an external leveler
for this purpose.
STEP 4. Adjust latitude
Without any payload, slightly loosen the 4x Latitude Locking Screws. Use the Latitude Adjustment Knob to
set the correct latitude value, as displayed in the Latitude Mark Window. Insert the Allen wrench into the
Latitude Adjustment Knob for more turning torque.
Figure 13. Adjust latitude
Two latitude ranges, 14~44° and 36~68°, can be set up for the mount head. To change the latitude range
from one to the other, both the Latitude Position Bolt and the Latitude Locking Screws need to be moved to
the correct locations (see photos below).
Loosen the Latitude Locking Screws just enough to adjust the latitude setting to 40°. Move the Latitude
Locking Screws with washers (one on each side) to the new locations revealed, do not tighten them just yet.
Allen wrench
Azi. Adj. Screw
Azi. Lock Screw
Azi. Lock Screw
Lat. Lock Screw
Lat. Adj. Knob
Lat. Mark

Figure 14. Latitude mark window
Unthread and remove the Position Bolt to its new location. Adjust the Latitude Adjustment Knob while
holding the brass eyebolt until it lines up with the Position Bolt. Secure the Latitude Position Bolt.
Figure 15. Change latitude range
STEP 5. Install Counterweight (CW) Shaft
Thread the CW shaft into the CW shaft mounting holes.
Figure 16. Install CW shaft
Position Bolt

STEP 6. Install Counterweight(s)
Before putting on CW, make sure the mount is at its zero position, i.e., CW shaft points to the ground.
Disengage the R.A. Gear Switch to set the R.A. axis free before loading the CW. Remove the CW
Safety Cap at the end of CW Shaft. Glide the CW over the shaft. Tighten the CW Locking Screw to hold the
CW in place. Place the Safety Cap back onto the shaft. Move the CW to the bottom of the shaft and tighten
the CW locking Screw.
Figure 17. Install Counterweight
You may need more CW for heavier payloads, or a smaller CW for lighter scopes.
GEM45 is equipped with a Vixen/Losmandy-D dual saddle. It can receive either a Vixen or a Losmandy-D
plate. Release the dovetail saddle locking knobs and slide the telescope dovetail plate into the saddle.
Tighten the saddle locking knobs.
STEP 7. Balance the Payload
After attaching the scope and accessories, the mount head assembly must be balanced in both DEC and
RA axes to ensure minimum stresses on the mount driving mechanism.
CAUTION: The telescope may swing freely when the R.A. or DEC Gear Switch is disengaged.
Always hold on to the mount and/or telescope assembly before releasing the Gear Switches
to prevent it from swinging, which can cause personal injuries and/or equipment damages.
Set the mount at Zero Position. Disengage both RA and DEC gear switches and move the mount to
horizontal position to check balance. Return to Zero Position for balance adjustment. Balance the DEC axis
by moving the scope with accessories back and forth in the mount saddle or within the scope mounting
rings. Balance the assembly in R.A. axis by moving CW along its shaft. Repeat the process until both DEC
and RA axes are balanced.
CAUTION: The balancing process MUST be done with Gear Switch at the total disengaged position!
Otherwise it might damage the worm system.

Figure 18. Balance a mount
Return the mount to Zero Position after balancing and engage gear switches.
STEP 8. Connect Cables
Plug in included 12V/5A DC power supply to the DC12V 5A socket, which is located at the end of the RA
axis.
Figure 19. Power connection
Connect the Go2Nova® 8407 Hand Controller to the HBX port on the mount main board. Plug GPS module
into the iPORT with a coiled cable. When powering on, GPS ON sign should be displayed at the upper right
corner of the hand controller.
Figure 20. Ports for cables

If you want to use the iPort for another accessory, such as WIFI adapter (iStarFi #7434), or electronic
focuser (#8451/#8452), you may disconnect the GPS module after it picks up satellites signals and displays
GPS OK on hand controller. (It takes about 1 to 2 minutes in normal conditions).
STEP 9. Setting up the Hand Controller
The GEM45 mount is equipped with a GPS receiver which will receive the 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 hand controller memory along
with longitude and latitude coordinates until they need to be updated.
A clear sky and open space outside is needed for the GPS to establish a link with the satellites.
To set up the controller, press MENU =>“Settings”:
Press ENTER and select “Set Time and Site”
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 to the satellites. In
the event that the GPS module is unable to establish a link, 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”
Daylight Saving Time Y
UTC -300 Minute(s)
2019-03-09 10:19:18
Longitude:W071d08m50s
Latitude: N42d30m32s
Northern Hemisphere
Set Time and Site
Beep Settings
Display Settings
Set Guiding Rate
Set Tracking Rate
Set Parking Position
Meridian Treatment
Set Altitude Limit
Set Eyepiece Light
Select and Slew
Sync. to Target
Alignment
Settings
Electric Focuser
PEC Options
Park Telescope
Edit User Objects
Firmware Information

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 +”.
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.
Set Observation Site Coordinates
The fifth and sixth 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.
Check the Hand Controller 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
required.
STEP 10. Set the Zero Position
Zero Position is the mount starting reference point which ensures the GOTO performance. Press MENU =>
“Zero Position” => “Search Zero Position” to let the mount search the Zero Position. Follow the instruction
on hand controller display to adjust the Zero Position if RA or DEC is not aligned. Or press MENU => “Zero
Position” => “Set Zero Position”, to manually set the mount to Zero Position. Loosen the DEC and R.A.
Gear Switches in turn to adjust the mount to the Zero Position. Engage the clutches after each adjustment.
STEP 11. Perform Polar Alignment
Polar Alignment with iPolar Electronic Polar Scope
GEM45 are equipped with an iPolarTM electronic polar scope. To perform polar alignment, please refer to
Appendix C. It is simple and fast, even the pole star or part of the sky is blocked. Steps are briefly outlined
below:

Download and install iPolar Software (first time use)
Connect a USB cable between the iPolar port on the mount and a computer USB port
Calibrate the iPolar Rotation Center (first time use)
Start polar alignment by following on screen instructions
BrightStar Polar Alignment
If you can’t use the iPolar for some reason, you may use the drift alignment for precise polar alignment. Or
may use two bright stars with Polar Iterate Align to do a polar alignment.
(1) Level the mount and set it to the Zero Position. Align the telescope to the R.A. axis of the mount.
If a finder scope is used, adjust it to be parallel to the telescope optical axis.
(2) Use the HC (MENU => “Alignment” => “Polar Iterate Align”) to display the azimuth and altitude
position of several bright stars near the meridian. Select one that is visible at a high altitude as
Alignment Star A. Follow the HC instruction to move Alignment Star A to the center of the
eyepiece using a combination of the Latitude Adjustment Knob and the “◄” or “►” buttons.
Press ENTER to confirm when the star is centered. Next, select a bright star that is close to the
horizon as Alignment Star B. Center it using the Azimuth Adjustment Knob and the “◄” or “►”
button (the “▲” and “▼” buttons are not used here). Press ENTER to confirm the settings.
(3) The telescope will now slew back to Alignment Star A. Repeat the steps above. The iteration can
be stopped when it is determined that the alignment error has been minimized. Press the BACK
button to exit the alignment procedure.
NOTE: It is highly recommended to use an eyepiece with an illuminated crosshair for accurate centering.
NOTE: The movement of the alignment star in your eyepiece may not be perpendicular depending on its
location in the sky.
STEP 12. Returning the Mount to Zero Position
After polar alignment and balancing OTA, return the mount to the Zero Position. Please check the zero
position after set up the mount or firmware update.