Sky-Watcher Skymax 127 AZ-GTi

Skymax 127 Optics: A 127mm, f/12.1 System

Sky-Watcher Maksutov-Cassegrains are take-anywhere telescopes, also ideal when working space is limited, with high-resolution, diffraction-limited optical systems multi-coated to maximize contrast and image sharpness, for terrestrial or astronomical use.

The aperture is 127mm with a 1540mm focal length (f/12.1). Focus is by moving the primary mirror with the knob at the rear: turn it slowly one way or the other until the image is sharp. The image usually needs fine refocusing over time because of temperature changes and flexure, and almost always after changing an eyepiece or adding or removing a Barlow lens.

AZ-GTi Mount: 11 lb Capacity with Freedom Find Encoders

The AZ-GTi carries 5 kg (11 lb) on its V-style saddle and its head weighs 1.3 kg (2.9 lb). It attaches to the tripod with a 3/8" socket, and Sky-Watcher includes an adapter for 1/4"-20 threads.

Freedom Find auxiliary encoders on both axes let the mount keep track of its position when you unlock the clutches and turn it by hand, so it does not lose its alignment; re-lock the clutches to return to motor control. The feature can be disabled in the SynScan app or hand control, and the manual recommends disabling it for the best pointing accuracy if you do not need to move the mount by hand after alignment.

• Motors: DC servo with a 6480 gear ratio and a tracking resolution of 2,073,600 counts/rev (0.625 arc-second).
• Freedom Find encoders: 1068 counts/rev (approx. 20 arc-minutes).
• Clutches: fully tighten them for motor-driven use, which the manual says gives the best pointing accuracy; half engage them to point by hand while the tube stays put; fully loosen them to move the telescope quickly.

SynScan App Control via Built-in Wi-Fi

The mount broadcasts its own Wi-Fi network (SSID SynScan_xxxx, no password by default), so a phone or tablet running the free SynScan Pro app for iOS or Android connects directly without internet. Use SynScan Pro to align the mount for celestial tracking, or Sky-Watcher's SynScan PTZ app for time-lapse photography.

Connect within 15 minutes of turning the power on, or the Wi-Fi turns off. The Wi-Fi configuration resets to factory default if you power the mount on with no hand control connected and no app operations over Wi-Fi for 4 hours. A SynScan hand control (sold separately) plugs into the HAND CONTROL port, an RJ-12 6-pin outlet.

Powering the AZ-GTi: 8 AA Batteries or an External DC Supply

The mount runs on 8 AA batteries (not included) in its battery compartment, or on an external power supply through the POWER input.

An external supply must deliver DC 7.5V to 14V, at least 0.75A, through a center-positive barrel plug with 2.0mm I.D. and 5.5mm O.D. Voltage outside this range might cause permanent damage to the motor controller or the hand controller. Do not use an unregulated AC-to-DC adapter: use a switching power supply with a 12V output and at least 750mA.

Assembly and Setup: Tripod, Extension Pier, and Accessory Tray

The kit includes an adjustable-height aluminum tripod, an extension pier and an accessory tray. Fully expand the three tripod legs on level ground and install the tray: align it, push down and rotate it to lock. The tray keeps the legs firmly expanded, which prevents the tripod from tipping over, so always use it.

For a long tube, the manual says to insert the extension pier between the tripod and the mount so the telescope cannot hit the tripod legs when it points high. Tighten the 3/8" bolt moderately, as over-tightening can damage the internal parts. Adjust the leg lengths to center the bubble level on the mount, then rotate the saddle until the dovetail groove is horizontal, loosen the dovetail locking knob, slide the dovetail bar in while holding the tube level, and tighten the knob. Fully loosen the altitude clutch while holding the tube to check the balance.

Magnification with the Included Eyepieces

Magnification is determined by dividing the telescope's focal length by the eyepiece's focal length. With the Skymax 127's 1540mm focal length, the two included 1.25" eyepieces provide distinct views:

• 25mm eyepiece: 1540 / 25 = 61.6x.
• 10mm eyepiece: 1540 / 10 = 154x.

Sky-Watcher's rule of thumb is about 2x per mm of aperture under good conditions, since air turbulence limits what you can usefully magnify, and skywatcher.com lists 254x as the highest practical power for its 127mm Maksutov.

Weight and Temperature

The tube weighs 9.37 lb. The AZ-GTi with tripod weighs 8.6 lb (about 4 kg fully assembled), easily fitting in carry-on luggage.

Sky-Watcher's Maksutov manual notes the image usually needs fine refocusing over time as the telescope adjusts to temperature changes, particularly before it has reached outside temperature. It gives no cool-down time.

Hand Control and Camera Control

The mount has ports for two accessories:

• SynScan hand control: plugs into the HAND CONTROL port; see the SynScan hand control manual for its use.
• DSLR control cables: the SNAP port is a stereo jack for a camera's shutter control port. Cables for Canon, Nikon, Olympus and Sony models can be ordered from a Sky-Watcher dealer. With a shutter release cable in the SNAP port, a 60-second preset fires continuous 60-second exposures until the cable is removed.

Solar Safety

Sky-Watcher's Maksutov manual gives this warning:

CAUTION: NEVER USE YOUR TELESCOPE TO LOOK DIRECTLY AT THE SUN. PERMANENT EYE DAMAGE WILL RESULT. USE A PROPER SOLAR FILTER FIRMLY MOUNTED ON THE FRONT OF THE TELESCOPE FOR VIEWING THE SUN. WHEN OBSERVING THE SUN, PLACE A DUST CAP OVER YOUR FINDERSCOPE OR REMOVE IT TO PROTECT YOU FROM ACCIDENTAL EXPOSURE. NEVER USE AN EYEPIECE-TYPE SOLAR FILTER AND NEVER USE YOUR TELESCOPE TO PROJECT SUNLIGHT ONTO ANOTHER SURFACE, THE INTERNAL HEAT BUILD-UP WILL DAMAGE THE TELESCOPE OPTICAL ELEMENTS.