iOptron SkyGuider Pro Star Tracker

Precision Tracking: A Φ88mm, 144-Tooth Worm Gear System

At the heart of the SkyGuider Pro is a tracking system engineered for long-exposure astrophotography. The oversized Φ88mm, 144-tooth aluminum alloy worm wheel, paired with a Φ15.2mm brass worm, a Φ35mm steel RA shaft and 4 bearings, minimizes periodic error for rounder stars. A DC servo motor with an optical encoder ensures consistent tracking rates, critical for sharp images with telephoto lenses, and a 144X fast slew in both directions makes framing quick.

• Celestial: The standard sidereal rate for stars, galaxies and nebulae.
• 1/2 Celestial: Half-speed tracking for nightscapes that balances sharp stars with a sharp landscape foreground.
• Solar and Lunar: Matched rates for filtered solar imaging and detailed lunar work.
• N/S: Reverses tracking direction for the Southern Hemisphere.

An 11 lb Payload with ST-4 Autoguiding

Despite its compact size, the SkyGuider Pro handles a balanced payload of up to 11 lbs (5kg) using the 1.35kg counterweight and Φ20x200 mm counterweight shaft supplied with every version. The DEC mounting bracket with camera mounting disk lets you balance a full-frame DSLR with a 70-200mm or larger telephoto lens, or a small wide-field refractor. The ST-4 compatible guiding port accepts an autoguiding camera for multi-minute exposures that bring out faint detail in targets like the Orion Nebula (M42), and the camera trigger port automates your exposure sequence.

Choose Your SkyGuider Pro Version

All three versions use the same 2.2 lb SkyGuider Pro head, 11 lb payload, internal battery, counterweight, counterweight shaft, DEC mounting bracket and padded carry bag. They differ in how you polar align: the type of polar scope and the base it sits on.

• SkyGuider Pro Full Package (AccuAlign): The classic configuration with the installed AccuAlign dark-field illuminated polar scope (~6º field of view) and the standard alt-azi base with a -30º to 65º latitude range. No computer is needed for alignment, making it the simplest self-contained travel kit.
• SkyGuider Pro Full Package w/ Precision AZ Base: Keeps the AccuAlign polar scope but replaces the standard base with the Precision AZ/EQ base, offering a 0º to 90º latitude range and fine ±5º azimuth adjustment knobs for faster, more controlled polar alignment at any latitude.
• SkyGuider Pro Full Package w/ iPolar: Replaces the optical scope with the installed iPolar electronic polar scope (30 arcsec resolution, 13° field of view) on the standard alt-azi base. Alignment runs on a Windows computer and works even when the pole star is blocked, ideal for imagers pushing longer focal lengths.

Polar Alignment: AccuAlign, iPolar and a 0º to 90º Precision Base

Accurate polar alignment is the most critical step for untrailed stars, and each SkyGuider Pro version approaches it differently. The AccuAlign dark-field illuminated polar scope keeps a finely engraved reticle visible against the night sky across an approximately 6° field of view. The iPolar instead uses a camera and plate-solving software to identify star patterns within its 13° field and guide you to an alignment precision of 30 arcseconds, displayed on your laptop screen rather than at a cramped eyepiece.

The standard alt-azi base, installed on the AccuAlign and iPolar packages, provides a -30º to 65º latitude range for use from a huge range of global locations. The Precision AZ/EQ base in the Precision AZ Base package extends this to 0º to 90º. Both bases use a Vixen-style saddle on a Φ80 mm platform with a 3/8” socket, a bubble level and ±5º of fine azimuth adjustment, so you dial in the final correction without moving the tripod.

Go-Anywhere Astrophotography: A 2.2 lb Platform with Internal Power

Designed for travel, the all-metal mount body weighs only 2.2 lbs (1kg), or 3.2 lbs (1.45kg) with the standard alt-azi base, making it an effortless addition to a camera bag or airline carry-on. Power is supplied by an internal 3.7V, 2000mAh Li-Poly battery, eliminating the need for external power packs and cable clutter. With a power consumption of only about 150 mA, it provides hours of continuous tracking on a single charge; the battery recharges via a standard MiniUSB port, reaching 80% charge in 5 hours, and the mount can also run directly from 5V DC. Firmware is upgradeable through the USB port.

iOptron SkyGuider Pro vs. Sky-Watcher Star Adventurer Pro

Both trackers are leaders in the portable astrophotography market with identical 11 lb payloads. The differences come down to power, gearing and alignment options.

• Integrated Power: The SkyGuider Pro's internal 2000mAh rechargeable Li-Poly battery offers a self-contained power solution, where the Star Adventurer relies on AA batteries or external USB power.
• Tracking Hardware: The SkyGuider Pro features a slightly larger Φ88mm worm wheel, contributing to its acclaimed tracking accuracy.
• Alignment Options: The SkyGuider Pro can be ordered with the iPolar electronic polar scope or with a micro-adjustable Precision AZ/EQ base, giving finer control over polar alignment than a standard equatorial wedge.