Celestron CGX 700 Maksutov Cassegrain Telescope

Maksutov-Cassegrain Design: A 22% Obstruction for High Contrast

The Maksutov-Cassegrain is a catadioptric design that uses both a mirror and a lens to form an image, delivering bright, sharp views virtually free of chromatic aberration. Its defining feature is a "secondary spot," a reflective coating on the inside of the thick corrector lens, which replaces a traditional secondary mirror assembly. The spot is significantly smaller than a traditional Schmidt-Cassegrain secondary mirror, giving the Mak its signature high-contrast views; the obstruction is 40mm (1.57"), 22% by diameter and 5% by area.

Because the secondary is a spot on the corrector, the telescope does not require occasional collimation like a Schmidt-Cassegrain. The larger, heavier Maksutov corrector takes longer to cool down and adjust to the ambient air temperature than a Schmidt-Cassegrain corrector of the same aperture.

180mm f/15 Optics: A 2700mm Focal Length for Planetary Detail

The CGX 700's 180mm aperture gathers 661 times more light than the unaided eye, reaching a limiting stellar magnitude of 13.9. The 2700mm focal length gives f/15, with a highest useful magnification of 420x and a lowest of 67x. The tube is 571.5mm (22.5") long, 222.25mm (8.75") in diameter and weighs 19 lbs.

Resolution is 0.52 arc seconds (Dawes) and 0.64 arc seconds (Rayleigh).

StarBright XLT is Celestron's coating system, built from three parts: enhanced multi-layer mirror coatings of aluminum, SiO2 and TiO2, with reflectivity fairly flat across the spectrum for both imaging and visual use; multi-layer anti-reflective coatings of magnesium fluoride and hafnium dioxide; and water white glass instead of soda lime glass for the corrector. Water white glass transmits about 90.5% of light uncoated, 3.5% more than soda lime glass, and reaches an average transmission of 97.4% with the StarBright XLT anti-reflective coatings.

The CGX Mount: 55 lb Capacity with a Belt-Driven DC Servo Drive

The CGX is an incredibly sturdy equatorial mount that rigidly supports the 700 Mak. It was designed more compactly, so the load sits closer to the R.A. axis and torque is reduced, and its structure was optimized with Finite Element Analysis, so it supports more weight than other mounts of similar mass. It carries 55 lbs, easily handling the tube along with a camera and accessories; expect a vibration-free setup even in somewhat windy conditions.

The low-cog DC servo motors run smoothly and have integrated optical encoders for accuracy. They drive the worm gears through a belt-and-pulley system instead of spur gears, to reduce gear backlash when the motor changes direction, and the steel worms, supported by precision bearings, are spring-loaded against brass worm wheels for a smoothly operating drive with minimal backlash and no binding. The latitude range is 3° to 65°, and the mount tracks at sidereal, solar and lunar rates in EQ North and EQ South.

2" Steel Tripod and Dual CG-5/CGE Saddle

The mount is supported by a heavy-duty adjustable tripod with 2" diameter steel legs and an extra-wide stance for improved stability. Graduated markings on the lower leg sections make it simple to extend each leg to the same height, simplifying the process of leveling the tripod in the field.

The dual saddle takes CGE (Losmandy D style) and CG-5 dovetails, and the 700 Mak connects directly to the CGX with its included CGE dovetail bar. With the mount, the height range is 1200.15mm to 1968.5mm (47.25" to 77.5").

NexStar+ and CPWI: A 40,000+ Object Database with Full PC Control

The CGX is fully computerized: the NexStar+ hand control has a database of 40,000+ objects, 100 user-defined objects and enhanced information on over 200 objects, with 2-Star, 1-Star, Solar System, Last and Quick Align, a hibernate mode that powers down without losing the alignment, and adjustable autoguiding rates. After a simple alignment procedure, the mount can automatically slew to any object in its database and track it precisely as it moves across the sky.

For advanced users, the mount offers two USB 2.0 ports for computer control. The port on the mount is used exclusively with the included CPWI telescope control software, which has a graphical interface and multi-point mount modeling. The hand control's USB port works with optional third-party software through an ASCOM driver. Two AUX ports support accessories such as StarSense AutoAlign. You also get Celestron's Starry Night Special Edition planetarium software and the SkyPortal mobile app to complete the software suite.

Astrophotography Ready: PPEC, Autoguiding, and Past-Meridian Tracking

The CGX is designed from the ground up for astrophotography. Celestron's All-Star Polar Alignment needs no polar finder scope (an optional one is available) and can usually be completed in about 15 minutes, even without a clear view of Polaris. All-Star Polar Alignment lets you polar align precisely without Polaris or a polar axis finder, using a convenient bright star. After a star alignment, the mount slews to where that star would be if the mount were accurately polar aligned, and you center it using only the latitude and azimuth adjustments, not the hand control. Permanent Periodic Error Correction (PPEC) lets you record the periodic error from tiny gear imperfections only once; the recording is kept in memory and then corrects the mount's periodic tracking error.

For more accuracy, a dedicated autoguider port connects an autoguiding camera to correct residual tracking errors. The CGX images through the meridian and does not need a meridian flip until the object is a full 20° past it. Optical switches on each axis stop the motors before the telescope can strike the mount, without loss of alignment; home position switches allow remote realignment after a power interruption; the cables run inside the mount; and the power jack uses a threaded barrel connector.

Visual Observing: 96x Magnification with the Included 28mm Eyepiece

The CGX 700 Mak arrives ready for visual observation with a complete set of 2" accessories. The included 28mm wide-field 2" eyepiece provides 96x (2700mm / 28mm). The package also includes a 2" 90° star diagonal for comfortable viewing and a 1.25" adapter, allowing you to use the vast range of 1.25" eyepieces and accessories.

An 8x50 straight-through finderscope is also included to help you manually aim the telescope and align the GoTo system. With the telescope's highest useful magnification rated at 420x, the tube accepts larger 2" accessories such as Celestron's 2" Barlow lenses, 2" eyepiece and filter kit and wide-field eyepieces.

System Portability: A 104.2 lb Kit that Disassembles Without Tools

Despite its robust build, the entire 104.2 lb system is designed for manageable transport to a dark sky site. The optical tube, mount head, tripod, counterweight bar and counterweights disassemble without tools, and transport is extremely manageable, even for one person. The only tool is the supplied hex key, which has a holder in the mount. The heaviest components are the 44 lb mount head and the 19 lb optical tube.

• Optical Tube Weight: 19 lbs (8.6 kg)
• Mount Head Weight: 44 lbs (20 kg)
• Tripod Weight: 19.2 lbs (8.7 kg)
• Counterweights: 2 x 11 lbs

Ergonomic carry handles are built into the mount head, and the tripod's accessory tray nests into the legs when collapsed, creating a stable package for transport and preventing loss of the tray.