Sky-Watcher Skymax 102 AZ-GTi Maksutov-Cassegrain GoTo Telescope Kit

Product Overview

The Sky-Watcher Skymax 102 AZ-GTi is a complete GoTo telescope: a 102 mm Maksutov-Cassegrain optical tube with 1300 mm of focal length at f/12.7, carried on Sky-Watcher's Wi-Fi controlled AZ-GTi alt-azimuth mount and its adjustable aluminium tripod. You align and drive it from the free SynScan Pro app on an iOS or Android phone or tablet, and it finds and tracks objects from a 42,900+ object database.

The whole system is small. Sky-Watcher publishes the tube at 12.25 inches (311 mm) long and 2.1 kg (4.6 lb), and the mount set - mount head, pier extension and tripod - at 3.9 kg (8.6 lb). In the box: the optical tube, a red dot finder, a 1.25-inch diagonal, Super 25 mm and 10 mm 1.25-inch eyepieces, and the AZ-GTi mount head, pier extension and tripod.

Who It's For

This is a good match if the Moon, the planets and double stars are what you want to look at, and you want the telescope to find them for you. Sky-Watcher notes that a Maksutov's focal length is five to seven times longer than an average Newtonian or refractor, so the supplied eyepieces already give 52x and 130x - useful planetary power without a Barlow.

It suits a first telescope well. The tube is sealed, the mount is small enough to carry out in one trip, and the app walks you through alignment with one bright star. If you are new to the sky, the GoTo database takes the guesswork out of finding things; if you already observe, it is a quick-setup second scope for nights when a larger instrument is more than the session needs.

Travellers, cottage observers and balcony observers get the most out of it: the mount set weighs 3.9 kg (8.6 lb), runs on eight AA batteries, and creates its own Wi-Fi network, so it works anywhere without mains power or a phone signal.

Key Features & Design

• 102 mm Maksutov-Cassegrain at 1300 mm, f/12.7: long focal length in a 12.25 inch (311 mm) tube, 4.625 inches (117.5 mm) in outer diameter.
• Borosilicate mirrors with Radiant Aluminum Quartz (RAQ) coatings: Sky-Watcher publishes 94% reflectivity for the Skymax series coatings.
• Corrector plate with Metallic High-Transmission Coatings (MHTC): the corrector reduces chromatic aberration and closes the front of the tube.
• AZ-GTi motorized alt-azimuth mount: DC servo motors with a 6480:1 gear ratio and 0.625 arc-second resolution, per Sky-Watcher's AZ-GTi manual.
• Built-in Wi-Fi and SynScan Pro app control: the mount acts as its own Wi-Fi access point; the app handles alignment, GoTo and tracking on iOS and Android.
• 42,900+ object database: complete Messier, Caldwell, NGC, IC and SAO catalogues plus user-defined objects.
• Freedom Find dual encoders: auxiliary encoders on both axes let you unlock the clutches and push the scope by hand without losing alignment.
• Tracking rates: sidereal, lunar and solar, plus alignment-free solar tracking.
• Nine slew speeds: 800x, 600x, 400x, 200x, 32x, 16x, 8x, 2x and 1x.
• Adjustable-height aluminium tripod: 1.25-inch (32 mm) diameter legs, accessory tray and pier extension.
• Camera shutter (SNAP) port: triggers a DSLR through a shutter-release cable with a 60-second preset exposure for timelapse sequences.
• Included: red dot finder, 1.25-inch diagonal, Super 25 mm and 10 mm 1.25-inch eyepieces, V-style dovetail, mount head, pier extension and tripod.

Optical / Mechanical Design

A Maksutov-Cassegrain places a deeply curved meniscus corrector at the front of the tube and a borosilicate primary mirror at the back. Light passes through the corrector, reflects off the primary to a secondary, and returns through a hole in the primary to the eyepiece. Folding the light path that way is how 1300 mm of focal length fits in a 12.25 inch (311 mm) tube. The corrector also reduces chromatic aberration and seals the tube, so dust stays off the mirrors and there is no alignment to do before observing. Sky-Watcher describes Maksutovs as generally regarded as producing a sharper image than Schmidt-Cassegrains, and the high-contrast, long-focal-length view is the reason the design is chosen for the Moon and planets.

The f/12.7 focal ratio is the trade-off: a long, slow light cone gives high magnification with ordinary eyepieces and a well-corrected view at high power, and a narrower field than a short-focus refractor on large, faint deep-sky objects.

The AZ-GTi head drives both axes through DC servo motors at a 6480:1 gear ratio, which Sky-Watcher's manual gives as 2,073,600 counts per revolution, or 0.625 arc-seconds per step. Separate from that drive, the Freedom Find encoders read each axis at about 20 arc-minutes, which is what lets the mount keep its alignment when you release the clutches and move the tube by hand.

Recommended Uses

• Lunar observing: 130x with the 10 mm eyepiece puts crater walls and rilles at a large scale.
• Planetary observing: Jupiter's cloud belts, Saturn's rings and Mars near opposition, with the mount tracking so the planet stays centred at high power.
• Double stars: long focal length and a sealed, stable tube suit close pairs.
• Bright deep-sky objects: the GoTo database locates brighter star clusters and globulars, best framed with the 25 mm eyepiece at 52x.
• Lunar and planetary imaging: a 1.25-inch planetary camera at 1300 mm gives a large image scale, with the mount tracking the target.
• Daytime and timelapse photography: the SNAP port triggers a DSLR at a 60-second preset, and the mount head also carries a camera on its own.
• Travel and grab-and-go: battery power and built-in Wi-Fi make it independent of mains power and cell coverage.

Compatibility and Accessory Notes

The mount's saddle accepts Vixen-style (V-style) dovetails, and the Skymax 102 arrives on one. The payload rating is 5 kg (11 lb); at 2.1 kg (4.6 lb) the tube leaves room for a heavier eyepiece, a planetary camera or a different V-style tube later. The mount head attaches to its tripod through a 3/8-inch-16 thread, and an adapter for 1/4-inch-20 is included, so the head also fits a standard photo tripod.

The visual train is 1.25-inch. Any 1.25-inch eyepiece, filter or planetary camera nosepiece fits the supplied diagonal. If you are planning a specific camera or a T-thread connection, send us the model and we will confirm the adapter you need.

Power comes from eight AA batteries in the mount (not included) or an external 12 V supply. Sky-Watcher's manual specifies DC 7.5 to 14 V at 750 mA or more, through a barrel plug of 5.5 mm outer and 2.0 mm inner diameter, centre positive. The head also has an RJ-12 port for an optional SynScan hand controller and a SNAP stereo jack for a camera shutter-release cable.

Good to Know Before You Order

• Control is through the SynScan Pro app. A phone or tablet running iOS or Android drives the mount over its own Wi-Fi network. A SynScan hand controller is not part of the kit; the mount has a port for one if you prefer physical buttons.
• Batteries are not included. The mount takes eight AA cells, or an external 12 V supply with a centre-positive barrel plug for longer sessions.
• This is an alt-azimuth mount. It tracks in altitude and azimuth, which suits visual observing, lunar and planetary imaging, and short exposures. Long-exposure deep-sky imaging calls for an equatorial mount.
• Focal ratio is f/12.7. The long focal length favours the Moon, planets and double stars; large, faint nebulae and wide star fields fit better in a short-focus telescope.
• Maksutovs need cooldown. The sealed tube and thick corrector reach outdoor temperature more slowly than an open tube, so the sharpest planetary views arrive after the optics have settled. Setting the scope out while you align covers most of it.
• The optical tube is also sold on its own. If you already own a mount, the Skymax 102 optical tube is available separately.

Frequently Asked Questions

Is it difficult to set up?

No. Setup is: tripod out, pier extension and mount head on, the tube's dovetail slid into the saddle and locked with one knob, then the diagonal and an eyepiece. With the mount switched on and your phone joined to its Wi-Fi network, the SynScan Pro app walks you through alignment - one-star, brightest-star, north-level or three-star. The optics are sealed and need no collimation. The one thing that takes patience is letting the tube cool, and that happens while you align.

What magnification do the included eyepieces give?

At 1300 mm focal length, the 25 mm eyepiece gives 52x and the 10 mm gives 130x. Any 1.25-inch eyepiece fits if you want other powers.

Do I need cell service or internet in the field?

No. The AZ-GTi creates its own Wi-Fi access point, and the app connects to it directly, so it works at a dark site with no signal.

Can I take photos with it?

Yes, for the Moon and planets: a planetary camera in the diagonal or visual back works well at 1300 mm with the mount tracking. The SNAP port also triggers a DSLR for timelapse sequences. Long-exposure deep-sky imaging is better suited to an equatorial mount and a faster telescope.

How is this different from the Skymax 127 AZ-GTi?

Same mount, tripod and accessory set. The 127 has a larger 127 mm aperture and 1540 mm focal length, and its tube weighs 4.25 kg (9.37 lb) against 2.1 kg (4.6 lb) here. The 102 is the lighter of the two and leaves more of the mount's 5 kg (11 lb) payload free for accessories.

Can I use the mount with something else later?

Yes. The saddle takes any V-style dovetail within the 5 kg (11 lb) payload, and the head threads onto a standard photo tripod through the included 1/4-inch-20 adapter.

Bottom Line

A complete GoTo Maksutov-Cassegrain: a sealed 102 mm, 1300 mm f/12.7 optical tube on Sky-Watcher's Wi-Fi AZ-GTi mount and tripod, with a red dot finder, a 1.25-inch diagonal and 25 mm and 10 mm eyepieces. It runs on AA batteries, is controlled from your phone, and is set up for the Moon, planets and double stars in a package you can carry in one trip.