iOptron CEM25P Equatorial GoTo Mount (1.5" Tripod)

BH #IO7100P • MFR #7100P
iOptron CEM25P Equatorial GoTo Mount (1.5" Tripod)
Key Features
  • Motorized Computer-Controlled EQ Mount
  • 128x Microdivision Stepper Motor
  • Go2Nova 8408 Computer Controller
  • 150,000+ Object Database
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With improved tracking accuracy thanks to its new low periodic error of less than ±10 arcsec, and larger gear switches on both axes to make access and adjustments easier, the iOptron CEM25P Equatorial GoTo Mount makes an ideal mount for most astronomy and astrophotography needs.
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iOptron CEM25P Overview

  • 1Description
  • 2Mount
  • 3Motors and Gears
  • 4Go2Nova 8408 Hand Controller
  • 5AccuAlign Polar Scope
  • 6Tripod

With improved tracking accuracy thanks to its new low periodic error of less than ±10 arcsec, and larger gear switches on both axes to make access and adjustments easier, the iOptron CEM25P Equatorial GoTo Mount makes an ideal mount for most astronomy and astrophotography needs.

It includes the motorized mount, the Go2Nova 8408 computer hand controller, a standard 1.5" tripod, and the AccuAlign illuminated polar scope. Its built-in 32-channel GPS receiver transmits accurate date, location, and time to the hand controller, so when you change your position, the telescope can be set up quickly with accurate information. For precise tracking, as required during long-exposure astrophotography or observation sessions, the CEM25P has the capability for you to program out the Periodic Error Correction (PEC) common to all worm gears. With a maximum payload capacity of up to 27 lb, this mount is ideal for most medium-to-large refractor, reflector, or catadioptric optical tube assemblies (OTAs) with Vixen-style dovetail plates, while still being able to handle imaging rigs.

The stepper motor is controlled by the Go2Nova hand controller. This system has an internal database of 150,000+ celestial objects, multiple alignment assistance procedures, and updatable firmware through the built-in serial port. With nine slew speeds and automatic tracking capabilities, finding and keeping objects centered in the field of view is easy whether you're viewing the fast-moving Moon or much slower deep-space subjects.


  • German equatorial design for smoother and more accurate tracking
  • Center-balanced "Z" design: Weight is placed over the center of gravity for greater stability, smoother movement, and quieter running
  • 27 lb payload capacity, excluding included counterweight
  • 0-60° latitude; ±10° azimuth adjustment range
  • Built-in 32-channel GPS receiver for accurate day, date, time, and location information
  • Spring-loaded Vixen-style dovetail saddle
  • Adjustable polar alignment even during tracking
  • Retractable counterweight bar prevents obstruction by the tripod; 20mm diameter accepts any compatible weights
  • Includes 10.4 lb counterweight
  • Integrated bubble level
  • Works in the Northern and Southern Hemispheres

Motors and Gears

  • Improved periodic error over previous model, reduced to less than ±10 arcsec
  • 1.8° stepper motor with 128x microdivision
  • 88mm, 144-tooth aluminum right ascension (RA) and declination (dec) worm wheels
  • Brass worm gears
  • 55mm RA and dec ball bearings provide smooth movement with minimal vibration
  • 35mm steel RA and dec axis shafts
  • Synchronous belt transmission improves tracking accuracy, with reduced vibration, especially with heavy loads
  • RA and dec gear switches release the gears for balancing OTA
  • Gear tension adjustment eliminates play in gears
  • Resolution: 0.17 arcsec
  • Low-power consumption: 0.35A (tracking), 0.6A (using GoTo)
  • Runs on included 110-240 VAC power adapter

Go2Nova 8408 Hand Controller

  • 150,000+ object database
  • Alignment procedures: Pole-star, One-star, Two-star, Three-star, Polar, Solar system
  • Slew speeds: 1x, 2x, 8x, 16x, 64x, 128x, 256x, 512x, 6°/sec (Max); Quiet mode
  • Real-time Periodic Error Correction (PEC) eliminates tracking errors for long-exposure astrophotography
  • Tracking rates: Sidereal, Lunar, Solar, King's, user-defined from 0.99x to 1.01x of Sidereal
  • Track Below Horizon option allows mount to track objects below the horizon that are still visible, such as when observing from a hill or rooftop/balcony
  • Computer control with planetarium software via integrated autoguiding port
  • Adjustable key and display brightness
  • Control for optional electronic focuser
  • Control optional illuminated polar scope light intensity
  • Fully compatible with mount's integrated GPS module to automatically determine day, date, time, location
  • 4-line/21-character LCD screen; backlit 18-button user interface
  • Database details:
  • Solar system: 9 objects, including the Sun, Moon, and planets
  • Named objects: 60 deep-sky objects with their common names
  • Messier catalog: 110 objects
  • NGC catalog: 7840 objects
  • IC catalog: 5386 objects
  • UGC catalog: 12,921 objects
  • Caldwell catalog: 109 objects
  • Abell catalog: 4076 objects
  • Herschel catalog: 400 objects
  • Named stars: 259 stars with their common names
  • Double/multi stars: 208 binary stars
  • Hipparcos catalog: 120,404 stars
  • 88 modern constellations with their names
  • 15 comets
  • 116 asteroids
  • 60 user-defined objects, including comets

AccuAlign Polar Scope

  • For accurate and fast polar alignment
  • Dark-field illuminated dial
  • Red LED illumination
  • Polar scope is not blocked by the dec shaft, allowing for re-alignment while mount is running


  • 1.5" stainless steel, two leg sections
  • Adjustable height of 25-42"
  • 48" maximum leg spread
  • Accessory tray with a locking leg spreader
  • Spiked feet for greater stability on uneven ground
  • Weight: 11.0 lb / 5.0 kg

iOptron CEM25P Specs

Mount TypeGerman Equatorial
GoTo CapabilityYes, Go2Nova 8408
Payload Capacity27 lb / 12.3 kg (without Counterweight)
MotorDual Axis
Tracking RatesKing, Lunar, Sidereal, Solar, User
Latitude Adjustment0 to 60°
Counterweight1 x 10.4 lb / 4.7 kg
Polar Axis ScopeYes (Built In)
Height Adjustment Range25 to 42" / 63.5 to 106.6 cm
Leg Diameter1.5" / 3.8 cm
Leg Sections2
MaterialsStainless Steel
Operating Temperature14 to 104°F / -10 to 40°C
Adapter12 VDC
Mounting SystemVixen Style
GPSYes, 32 Channels
Dimensions12 x 11 x 6" / 15.2 x 27.9 x 30.1 cm (Mount)
Weight10.4 lb / 4.7 kg (Mount)
11 lb / 5 kg (Tripod)
Packaging Info
Package Weight37.35 lb
Box Dimensions (LxWxH)29 x 14 x 14"
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