Onstep Mark III User manual

I
GREETINGS
Thank you for purchasing Mark III equatorial mount. The Mark III is
a symbol of vitality and modern technology. Meanwhile, it is a
lightweight and portable German equatorial mount with a delicate
harmonic gear system. Its outstanding payload capacity caters to
most desires in sky observation and astrophotography. Mark III
boasts quick dynamic response, precise tracking ability, accurate
data-transmission and processing. Mark III is easy to operate and
extensively compatible with existing astronomy software or
applications. It’s a great option for astronomy activities, a handy
and functional helper along your journey to the universe
exploration.
This instruction manual is designed for anyone who use Mark III
equatorial mount. The instruction manual will introduce you the
proper steps and warn you about the potential improper thus
dangerous operations or situations. Please be sure to thoroughly
read the instruction manual before you assembly and use Mark III
equatorial mount, and strictly follow these steps illustrated in it.
Also, you should keep it in a place where you can easily refer to
when you operate Mark III equatorial mount. The operator himself
should be responsible for any damage to the equipment or personal
injury caused by improper operations.

II
Mark III equatorial mount is powered by Onstep, a fantastic open
source software. We would like to express our sincere gratitude to
the developers and all relevant contributors who have helped a lot
to improve the Onstep software. We will also do our best to make
possible improvements and modifications to Onstep based on the
practical operations to make this software and thus our equatorial
mount perform more smoothly.
If users need Onstep source code, please contact us at:
bonnie@sharpstar-optics

III
SAFETY PRECAUTIONS
This instruction manual will help you operate the Mark III equatorial
mount effectively and safely. Please be sure to read this manual
before any operations and strictly follow the steps illustrated in it.
1. MARKIII has a automatic braking system used in accidental
power-off situations. Before rebooting the Equatorial mount, it
would be better to take down the telescope for safety reasons.
After powering on the MARKIII, manually adjust to the “Home
“position and reset the “Home” position of the mount.
2. After the MAKRIII is powered on, the automatic tracking will be
automatically turned on, if the mount is not used for a long time
after opening, it is recommended to manually turn off the tracking
to avoid accidental damage due to the mount’s long-term rotation.
3. MARK III GOTO Speed Recommendation:
Name
Symbol
Actual Speed
Recommended Load（without
counterweight）
Fastest
2×
4 deg/s
≤12kg
Faster
1.5×
3 deg/s
≤22kg
Default Speed
1×
2 deg/s
≤22kg

IV
Name
Symbol
Actual Speed
Recommended Load（with
counterweight）
Fastest
2×
4 deg/s
≤12kg
Faster
1.5×
3 deg/s
≤22kg
Default Speed
1×
2 deg/s
≤28kg
If ignored, it can cause damage to your equipment or personal
injury.
More information about the current step.

V
WARNING!
1. Do not directly look at the sun with your naked eyes through your
telescope or finder scope when you use Mark III equatorial mount.
Or it can cause permanent and irreversible damage to your eyes.
Observe the sun with a dedicated solar filter.
2. Do not place Mark III in places that is wet and damp. Or it may
cause erosion to the parts of equatorial mount, which may result in
inaccuracy, electrical shock and even fire.
3. Do not try to disassembly any part of Mark III equatorial mount
when you can’t find any references in the instruction manual. Or it
may cause inaccuracy of Mark III equatorial mount and even
personal injury.
4. Please be sure to keep children away from counterweight pin,
thumb screws, Allen wrench of M1.3 or any other tiny components.
Or it may cause suffocation.
5. Do not plug or unplug the power cord, hand controller cable and
other cables by force. Or it may cause electrical shock and even
personal damage.
6.Please don’t plug off the R.A. ,Dec and hand controller connecting

VI
cable when the mount is working, or it may cause the mount to
break down
7. Please be careful when you carry, assembly or disassembly the
main body, counterweight, counterweight bar and other heavy
components. Or it may cause damage to the equipment or even
personal injury.
8. Please be sure to place Mark III on flat ground before you observe
or astrophotograph. Or the equatorial mount may fall over which
may cause damage to the equipment or personal injury.
9. Do not wipe the surface of Mark III with corrosive liquid. Or it
may cause damage to the surface painting and the equatorial
mount.

VII
STORAGE AND PROTECTION
1. Please be sure to return your equatorial mount to home position
if you want to leave your telescope on Mark III equatorial mount
after your observation or astrophotography, then cut off the
electricity. Or the equatorial mount may fall over which may cause
damage to the equipment or even personal injury.
2. Do not expose uncovered telescope to direct sunlight. Or this
may cause a fire.
3. Do not expose Mark III equatorial mount to direct sunlight, heavy
moisture or dust. Keep Mark III at places that is dry and clean.
4. Keep children away from Mark III equatorial mount. The mount
may fall over, which may cause damage to the equipment or even
personal injury.
5. If Mark III is stained, please clean Mark III equatorial mount with
dedicated cleaning cloth and solvent. Do not clean the surface of
Mark III with strong corrosive detergent. Or it may poison the
surface painting of Mark III equatorial mount.
6. If Mark III is not used for a long time or for long-distance
transportation, please adjust the altitude angle to 30 degree and
put it into the original protective box.

VIII
BASIC OPERATION STEPS
Users, especially those who first operate Mark III, must follow the
steps below. Or it may cause inaccuracy of Mark III equatorial
mount.
1. First, users should unpackage and assembly Mark III under the
instruction of this manual.
2. Before observation or field astrophotography, point Mark III
equatorial mount approximately to North (or South). (See 3.1)
3. Altitude and azimuth adjustment. (See 3.3)
4. Power your Mark III mount (with proper voltage), upload your
current time, longitude and latitude to Mark III equatorial mount
(See 4.3.1); change your mount’s hotspot name (See 5.3.2)
5. N-star alignment. (See 4.3.3)
6. Polar alignment. (See 4.3.4)
7. Reset the home position of Mark III equatorial mount. (See 4.3.2)

IX
CONTENT
SAFETY PRECAUTIONS ...................................................................................................III
WARNING! ..................................................................................................................... V
STORAGE AND PROTECTION ........................................................................................VII
BASIC OPERATION STEPS ............................................................................................ VIII
CONTENT .......................................................................................................................IX
1 Components and Specifications ..................................................................................1
1.1 Basic Function of an Equatorial Mount..........................................................1
1.2 Specification of Mark III ................................................................................. 2
1.3 Package Contents ........................................................................................... 5
1.4 Components of Main Body ............................................................................ 6
1.5 Ports and lights .............................................................................................. 9
1.6 Components of Tripod ................................................................................. 10
1.7 Basic Information of Hand Controller .......................................................... 11
1.8 Diagram of the hand controller connection hole ........................................ 13
2 Assembly Steps ......................................................................................................... 15
2.1 How to set up the Tripod ............................................................................. 15
2.2 How to Assemble the Main Body ................................................................ 17
2.3 How to Assemble Counterweight ................................................................ 19
2.4 Power Connection and controller ................................................................20
3 Mechanical adjustment ............................................................................................ 23
3.1 Find the North ..............................................................................................23
3.2 How to Level Mark III ................................................................................... 24
3.3 How to Adjust Altitude and Azimuth ........................................................... 24
3.4 How to Set up a Telescope ........................................................................... 28
4 Operate with Hand Controller.................................................................................. 30
4.1 Basic Operation of Hand Controller .............................................................30
4.2The battery installation steps for the hand controller..................................59
5 Operate with Smartphone ........................................................................................ 61
5.1 Operate with Onstep App ............................................................................ 61
5.2 How to Connect ........................................................................................... 61
5.3 Information Bar ............................................................................................64
5.4 Initial Settings of Time and Location ............................................................66
5.5 Home Position ..............................................................................................69

X
5.6 Other Functions ........................................................................................... 72
5.7 How to Connect by Web .............................................................................. 91
6 Operate with Computers.......................................................................................... 94
6.1 How to Connect with Computer .................................................................. 94
7 Operate with ASIAIR ..................................................................................................96
8 FAQ ..........................................................................................................................100
APPENDIX ...................................................................................................................102
Menu of Onstep App ........................................................................................102
Menu of Hand Controller .................................................................................107

1
1 Components and Specifications
1.1 Basic Function of an Equatorial Mount
When we observe the sky in the northern hemisphere, we can find
that all the stars in the sky are constantly rotating around the Polaris,
approximately one turn a day. It’s an interesting phenomenon
caused by the earth rotation which is called diurnal motion. If we
need to observe, especially image an object in a quite long time, we
have to offset the influence the star rotation, keeping the object
staying at the center of our field of view, that’s why an equatorial
mount is created.
When use Mark III equatorial mount, we polar-align the mount to
make sure that its R.A. axis is pointing directly to the Polaris which is
near the Northern Celestial Pole or NCP. Mark III will turn around its
R.A. axis, tracking an object at a set and constant rate. Thus the
object will be kept at the center of our filed of view, achieving
long-time exposure.

2
1.2 Specification of Mark III
ITEMS
SPECIFICATION
Weight of the main body (without
counterweight and counterweight bar )
7.65KG
Weight of special carbon fiber tripod (with
extension tube)
4.95KG
Total weight (without counterweight and
counterweight bar)
12.6KG
counterweight and counterweight bar
A standard 5KG counterweight and a counterweight bar
(304 stainless steel)
Dovetail saddle
Standard 200mm Losmandy & Vixen style dovetail saddle
Dimension
The diameter of the main body’s base is 160mm, the
maximum height of the main body is 38cm, and the
maximum width is 30cm
Dimension of tripod (including a one-stage
extension tube)
82cm of height and 98cm of width when expanded, 93cm
of height when retracted
Level adjustment of tripod (with a bubble level)
height adjustment within 2.5cm, with fine-tuning and
locking system
Latitude adjustment
15-90°（90°is the motorized Alt-Azimuth mode）
Azimuth adjustment
±4°
Effective payload
≤22kg (without counterweight)
≤28kg (with counterweight)
Note: these are measured when the distance between
telescope’ s central axis and the mounting surface of the
equatorial mount is less than 150mm
Reduction/Gear Ratio
R.A. axis 1: 1000

3
Dec. axis 1: 1000
PE Cycle Error
<±20”
PE Cycle Time
432 seconds
Slew speed
Maximum slew speed:4 deg/s
default slew speed: 2 deg/s
Note: switch to default or slower slew speed when carrying
a heavy or bulky telescope
Guide speed
2x，4x，8x，20x，48x，120x，180x，240x，360x，480x，
710x，950x
Harmonic reducer type
20mm 1:100 Harmonic reducer
Motor
42mm stepping motor with automatic braking system (used
in power-off situations)
Power enter (with a standard 24V power
adapter and 12V to 24V power adapter)
24V stable power supply
Operating voltage
950mA
Standby voltage
475mA
Data transmission
Support WiFi wireless connection and USB wired
connection
Guiding Port
Through USB connection
Hand Controller
CNC-machined controller with build-in celestial database
Compatibility
MARK III is perfectly compatible with ASCOM & INDI
platforms, various commonly-used astronomy software,
mobile phone apps, star atlas software, etc., the mount can
be controlled via smartphones/laptops/tablets etc. through
WIFI or USB connection
Star alignment
Supports up to 9-star alignment

4
Home sensor style
Electrical zero position
Working temperature
-25℃-40℃
Polar alignment scope port
Built-in electronic polar alignment scope port with
quick-release system
PHD2 guiding test
±0.5”
Note: the specifications are subject to change without notice and all rights are reserved.

5
1.3 Package Contents
NUMBER
ITEM
NOTE
1
Hand controller
to control and operate Mark III equatorial mount
2
Boost converter
12-24V boost converter×1
3
Tool package
Thumb screw for fixing the mount on the tripod×2; M1.3 Allen
wrench×1; altitude adjustment bar×1; M5 Allen wrench×1;
4
Power package
24V power adapter×1; power cable×1
5
Counterweight bar
with a thread at the bottom
6
Main body
7
Counterweight
to balance the mount

6
1.4 Components of Main Body
NUMBER
ITEM
NOTE
1
Dovetail saddle
to accommodate a dovetail plate
2
Safety screw
to tighten and secure dovetail plate slid into the dovetail saddle
3
Platform for polar
scope
for installing QHY polar scope

7
NUMBER
ITEM
NOTE
4
Declination axis
body
5
R.A. axis body
6
“Home”position
symbol
When arrows are aligned, here is the home position
7
Altitude
coarse-tune shuttle
8
Bubble level
9
Installing hole
to install counterweight bar and counterweight
10
Connecting cable
to connect R.A. and Declination axis body
11
Altitude fine-tune
screw

8
NUMBER
ITEM
NOTE
12
Altitude fixing
screw
loosen before adjusting the altitude angle
13
Azimuth adjustment
screw
14
Azimuth adjustment
post
15
Altitude adjustment
grub screw
to fix the altitude adjustment shuttle
16
Connecting cable
to connect R.A. and Declination axis body
17
Fixing thumb screw
to fix the main body on the platform of the tripod

9
1.5 Ports and lights
NUMBER
ITEM
NOTE
1
Connection port
to connect the Mark III and the hand controller

10
1.6 Components of Tripod
NUMBER
ITEM
NOTE
1
Tripod head
for installing Mark III main body
2
Leg brace
3
Stainless ferrule
support tripod;
adjust the height of tripod
4
Central column
5
Tripod leg