In addition to a precision synchronous belt transmission that improves tracking accuracy while reducing vibration, the iOptron CEM40EC Equatorial GoTo Mount gets an upgrade from the standard CEM40 mount that brings periodic tracking errors down to less than 0.25 arcsec by using high-resolution encoders and their Real-Time Periodic Error Correction (RPEC) system. The encoders and RPEC continuously monitor tracking accuracy and make any necessary corrections as soon as errors are detected. This is an invaluable upgrade for astrophotographers who practice long-exposure techniques to keep their star fields tack sharp without streaking or blurring.

The CEM40EC has a payload capacity of 40 pounds and an 8" saddle that accepts both Losmandy and Vixen-style dovetail plates, so it can handle just about any optical tube assembly (OTA) and gear you have. This version of the CEM40EC includes the motorized mount, the Go2Nova 8407+ computer hand controller, an upgraded tripod to their LiteRoc model, the iPolar electronic polar finder, and a hard carrying case to safely transport everything except the tripod.

Motorized Computer-Controlled EQ Mount    High Tracking Accuracy with RPEC    Go2Nova 8407+ Computer Controller    212,000+ Object Database    Built-In 32-Channel GPS Unit    Built-In iPolar Electronic Polar Finder    8" Dual-Fit Vixen & Losmandy Saddle    40-Pound Payload Capacity    Hard Case for Mount Head    Adjustable-Height LiteRoc Tripod

• German equatorial configuration provides smooth and accurate celestial tracking for observation or astrophotography
• Center-balanced "Z" design places the weight over the mount's center of gravity to provide greater stability, smoother movement, and quieter running while requiring less counterweight
• 40-pound payload capacity, excluding included counterweight
• 0-60° latitude; ±6° azimuth adjustment range
• Integrated iPolar electronic polar finder works globally; no Polaris (north) or Sigma Octantis (south) necessary; no need to rotate the mount during alignment
• Built-in 32-channel GPS receiver for accurate day, date, time, and location information
• Large dual-fit 8" Losmandy and Vixen-style dovetail saddle accommodates most OTAs on the market today
• Retractable 11" long counterweight bar prevents hitting the tripod or otherwise interfering with the mount's movement while still providing a long adjustment range for proper balancing
• 11-pound counterweight included
• Cables are run internally to avoid cable wrap during long observation sessions and snag hazards

• Real-Time Periodic Error Correction system with high-resolution encoders continuously and automatically identifies and corrects intrinsic tracking errors to constantly improve accuracy over time
• Precision tracking with less than ±0.25 arcsec error
• 1.8° stepper motor with 128x microdivision
• 110mm, 216-tooth right ascension (RA) and declination (dec) worm wheels with zero backlash
• 68mm RA and declination ball bearings provide smooth movement with minimal vibration
• 45mm steel RA and dec axis shafts
• Synchronous belt transmission improves tracking accuracy, with reduced vibration, especially with heavy loads
• RA and declination gear switches release the gears for balancing OTA
• Precise 0.08 arcsec (200 pulse/sec) motor resolution
• Low-power consumption: 0.6A (tracking), 0.9A (using GoTo)
• Runs on included 12 VDC 5A power adapter; plugs into a standard 110-240 VAC North American outlet

• 212,000+ object database includes the moon, sun, planets, stars, comets, asteroids, and constellations
• Multiple assisted alignment procedures use the built-in GPS module and iPolar electronic polar finder
• Slew speeds: 1x, 2x, 8x, 16x, 64x, 128x, 256x, 512x, MAX (4.5°/sec)
• Tracking rates: Sidereal, Lunar, Solar, King's, user-defined from 0.99x to 1.01x of Sidereal
• Star Identification function will tell user what star the mount is pointed at after proper alignment
• Computer control with planetarium software via integrated autoguiding port
• 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, and location
• Serial port for firmware upgrade
• Adjustable key and display brightness
• Integrated heater that ensures the LCD display will work at temperatures as low as -4°F (-20°C)
• 8-line/21-character LCD screen; backlit 19-button user interface

Database details:

• Solar system: 9 objects, including the sun, moon, planets (& Pluto)
• Named objects: 92 deep-sky objects with their common names
• Messier catalog: 110 objects
• NGC catalog: 7840 objects
• IC catalog: 5386 objects
• PGC catalog: 73,197 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 stars
• Hipparcos catalog: 120,404 stars
• 88 modern constellations with their names
• 15 comets
• 116 asteroids
• 60 user-defined objects, including comets

• Innovative design provides the stability of a large 2" tripod, but with lighter 1.75" diameter legs
• Specially designed leg cuffs and sockets and locking levers add rigidity with less wobble when legs are fully extended
• Spreader locks legs into position to add stability and vibration suppression
• Minimum height: 30" (76.5 cm)
• Maximum height: 47" (116.8 cm)
• Weight: 15 pounds

• Safely carry, transport, and store mount head, hand controller, and counterweight shaft
• Aluminum case with reinforced corners
• Dual latches
• Molded hinged handle
• Foam-lined lid and custom-cut foam insert prevent items from shifting

Related Questions and Answers

Q: 1. Can you add gps to this setup?

A: Yes, iOptron GPS Module for CEM26, CEM40, GEM28, GEM45 Mounts BH #IO8438 • MFR #8438 https://www.bhphotovideo.com/c/product/1625961-REG/ioptron_8438_gps_module_for_cem26.html

Q: 2. What is a recommended Tripod other than the 1.75 inch carbon fiber that ioptron offers?

A: For the iOptron HAE29 GoTo Alt-Az/Equatorial Mount one needs to make sure one uses a tripod with the correct mount for the head. The iOptron Carbon Fiber Tripod (21-36.8") is the best option, BH #IO8061 (https://bhpho.to/3LtX21A).

Q: 3. Does this version of the mount come with the one-piece upgraded worm gear?

A: Yes it does, on both axis.

Q: 4. How do you use this mount at 6 North latitude?

A: It has a 15-70° latitude adjustment range. Observers at lower latitudes will prefer to leave the alignment peg between two legs to avoid the counterweight from making contact with the tripod leg when the counterweight is in the lowest part of its swing.

Q: 5. Will this mount handle the SkyWatcher 300mm (i.e., 12") aperture OTA?

A: The Sky-Watcher EQ6-R Pro Equatorial GoTo Mount with Tripod Kit BH #SKEQ6RV2 • MFR #S30300 maximum payload is 44 lbs. the Sky-Watcher Quattro 300P OTA Imaging Newtonian 12" is 57 lbs.

Q: 6. Is this the regular HEQ5 or the HEQ5 PRO?

A: This is the information from Sky-Watcher website. No mention of the word pro. https://www.skywatcherusa.com/products/heq5-mount

Q: 7. Is the tripod section on this mount the same tripod as is used in the Celestron VX Advanced mount?

A: No the Celestron CGEM II Tripod that comes with the Celestron CGEM II GoTo German Equatorial Mount is not the same tripod that comes with the Celestron Advanced VX GoTo German Equatorial Mount.

Q: 8. Is there a case that will fit the head unit without the tripod

A: Probably one of the Pelican trunk cases. depending on the head dimensions only.

Q: 9. Is this the newer model which includes a USB A port for direct PC connection (by passing the hand controller)?

A: This is Sky-Watcher product # s30300 as per Sky-Watcher website: https://www.skywatcherusa.com/products/eq6-r-pro

Q: 10. Does it come with a polar alignment scope or is that purchased separately?

A: The Celestron CGEM II GoTo German Equatorial Mount with Tripod (B&H # CECGEMIICMK) does not include the polar alignment scope; it is an optional accessory: the Celestron Polar Axis Finderscope, B&H # CEFSPA (https://bit.ly/4ecS8EY).