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A Review of the iOptron SkyTracker Pro Star-Tracking Camera Mount - Updated

Updated: Feb 14, 2021

Modern DSLRs and advanced mirrorless cameras are so good in low light that they can make images of the Milky Way from a stationary tripod that show stars as points (well, almost as points). Film cameras and early DSLRs required such long exposures that Earth’s rotation turned the stars into obvious streaks. Despite recent advances in technology, however, shooting the Milky Way with a stationary camera still requires using a high ISO. Even with today’s best cameras, using a high ISO generates noise, reduces resolution, and compresses dynamic range (the difference in brightness between the darkest detailed shadow and the brightest detailed highlight). And while the stars may appear to be round in a JPEG sized for the web, close examination of a big print reveals that the stars are actually rendered as short streaks.

For decades, astronomers have used equatorial mounts that moved their telescopes in time with the stars, counter-acting the Earth’s rotation so that the stars were rendered as points. Until fairly recently, however, equatorial mounts were big, heavy, expensive, and designed to work with telescopes. Few landscape photographers used them. Now the explosion of interest in wide-field landscape photography at night has led several companies to make relatively small, lightweight, and affordable star-tracking devices designed for use with DSLRs.

As part of my research for my book Dusk to Dawn: a Guide to Landscape Photography at Night (Rocky Nook, spring 2018), I bought a compact equatorial mount from iOptron called the SkyTracker Pro. (Writing a book is always a great excuse to buy new toys…) The mount has two parts, the battery-driven, motorized tracking device itself and the alt-azimuth base, a piece of hardware that allows you to make precise adjustments of the altitude (orientation in the vertical plane) and azimuth (orientation in the horizontal plane) of the tracking device.

An iOptron SkyTracker Pro and counterweight, mounted on a Really Right Stuff BH-55 ballhead. An Acratech Ultimate Ballhead supports a Canon 5D Mark IV and Canon 16-35mm f/2.8 L III lens.

Theoretically, you could mount the tracking device directly to your tripod head with a standard ¼-20 mounting screw. As a practical matter, however, using the alt-azimuth base makes setup much easier. Equatorial mounts can counteract the movement of the stars only if one axis of the mount is aligned with the axis of Earth’s rotation—in other words, if the axis of the mount points to Polaris, the North Star. Without the alt-azimuth base, you must perform a precise adjustment of the SkyTracker Pro’s orientation using only the controls on your tripod head. Achieving that level of precision is quite difficult. The alt-azimuth base simplifies that task. In addition, the base includes a bubble level. The altitude of Polaris is always equal to your latitude. A topographic map or a smart-phone app like Sun Surveyor will give you the latitude of your current position. Leveling the base, then setting the altitude