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The winter Milky Way is visible above Orion in this 30-second exposure atop the iOptron SkyTrackers. (Terence Dickinson)

Review: iOptron’s SkyTracker Ultraportable Camera Mount

Compact and practical tracking platforms upgrade your DSLR’s astro-potential without the need for a telescope mount — or a telescope. We test the latest entry.

Anyone who has turned a camera to the night sky immediately discovers new rules of photography. True, some cameras have a “starry night” setting requiring the use of a tripod. Typically, this tells the camera to take up to a 15-second exposure. But when you examine the resulting picture, the stars record as tiny hyphens rather than points.

iOptron Orion rising
The winter Milky Way is visible above Orion in this 30-second exposure taken with a Canon 6D digital SLR camera at ISO 2000 and a 24mm lens at f/2.8. With the camera atop the iOptron SkyTracker, stars remain pin-sharp. A mild mist filter emphasizes the brighter stars, making the constellations more conspicuous. (Terence Dickinson)

Welcome to the Earth’s rotation. The longer your exposure, beyond 10 seconds or so, the more Earth turns on its axis, and the hyphens soon become trails. Star trails can be artistic, but what most astro-imagers want is realistic pinpoint stars and lots of them.

iOptron SkyTracker
The SkyTracker in its working configuration requires a sturdy camera tripod. A right-angle viewfinder adapter is another essential accessory to avoid awkward contortions when framing a shot. (Terence Dickinson)

The solution is an equatorial mount with motorized drive (what used to be called a clock drive) to precisely counteract the Earth’s rotation. In its standard form, the equatorial mount’s polar axis is angled to aim at the north celestial pole, near Polaris, the North Star.

As DSLR cameras have become increasingly capable of amazing night-sky performances, the idea of a highly portable equatorial mount for such cameras has come of age. The latest entry in this category is the iOptron SkyTracker, for use on a solid camera tripod. For this review, iOptron loaned us a unit from stock.

iOptron SkyTracker
The basic prin­ci­ple of the SkyTracker (and equa­torial mounts in general) is to have the drive axis geared to exactly counteract the Earth’s rotation. To function astronomically, the drive axis must be aligned with the Earth’s rotation axis. This is accomplished on the SkyTracker with the (supplied) polar axis alignment scope. (Terence Dickinson)

The SkyTracker requires a ball-head mount, a common camera accessory, to allow the camera to be locked in any direction while being guided on the sky (the ball head is shown at upper right between the camera and the aluminum drive head on the tracker). Apart from that, the SkyTracker is entirely self-contained, making it ideal for the travelling astronomer.

The tracker has a payload capacity of three kilograms, so it can double as an equatorial mount for a travel telescope such as a 60mm to 70mm apo refractor that can be fitted on the ball head.

iOptron controls
The SkyTracker’s back panel is shown here. Four AA batteries provide tracking power for 24 hours or more.

One of the best features of this product is the polar-alignment scope provided with the unit that slides into a dedicated socket and is secured by a thumbscrew. The reticle in the polar scope is cleverly illuminated by a red LED in the tracker socket. Using the Polaris offset ring, I was able to quickly align the tracker with enough accuracy for 6-minute exposures with a 35mm lens.

The Polaris offset technique I use is to place Polaris on the 40′ reticle ring at the same angle that Kochab, the brightest star in the Little Dipper’s handle, is in the naked-eye sky. With practice, this can be done with both eyes open, one looking at the real sky, the other through the polar scope.

Priced at $400, the iOptron SkyTracker comes with a user manual and a soft carry case. This solid, well-designed tracking mount can open new astrophotographic possibilities for you and your DSLR camera. Highly recommended.