A motorized star tracker camera mount is a key piece of kit for long-exposure astrophotography – and in this guide we show you some of the best star trackers available.
But why does your DSLR or mirrorless camera need a star tracker for astrophotography? The trouble with photographing the night sky is that the stars move, or rather, they appear to. Earth rotates once every 23 hours 56 minutes and 4 seconds – and so do you – so the position of stars appears to constantly move. Try a long exposure of just 30 seconds and you’ll get blurred stars. The ultimate proof of that is a star-trail photo, which literally shows the path of stars in the night sky over a few hours.
• See also: Best timelapse cameras
So what do you do if you want to shoot the night sky with long shutter speeds over 30 seconds – and as long as four or five minutes? Cue a rotating star tracker, a device you place between camera and tripod, which when aligned with the north celestial pole (if you’re in the Northern Hemisphere) or the south celestial pole (if you’re in the Southern Hemisphere) will keep your camera in sync with Earth’s rotation. That’s so useful because long exposures of two minutes or more are necessary to capture enough light, color, and detail to properly reveal the Milky Way, as well as faint celestial sights such as star fields, galaxies, nebulae, and even gas clouds.
For close-ups, astrophotographers tend to strap their cameras with zoom lenses to telescopes mounted on equatorial mounts; star-trackers like these are all about portability, and are best used with a wide-angle (which are generally considered the best lenses for astrophotography). However, don’t forget that a slowly moving platform means a sharper, lighter-filled and cleaner star fields, but a blurred foreground, so you need to be prepared to do some blending and post-processing whenever you use a star tracker.
There are a few issues you need to be aware of when purchasing a star tracker; portability, the weight they can hold, the ease of polar alignment, and battery life. There are several star trackers available, though all are different, meeting slightly different requirements. It all depends on what your goals are.
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If you’re restricted on the weight of your camera bag, but need a long battery life, look no further than the iOptron SkyTracker Pro. What's more, and over the older generation of SkyTracker, we have to say that the feel of the Pro has drastically improved – despite iOptron switching out the metal components, we are left with a set up that doesn't feel that it's going to fall apart during observations: everything is welded beautifully together. Seasoned astrophotographers may miss the cast metal fixtures, but the SkyTracker Pro doesn't suffer without them.
A much more basic version than the brand’s souped-up iOptron SkyGuider Pro (featured below), the SkyTracker Pro’s built-in battery lasts for 24 hours, though it can be recharged via an external battery via micro USB. The tracker has a loading capacity of 3kg: loading a DSLR even slightly heavier than this caused the SkyTracker Pro to struggle somewhat – a counterbalance will rectify the problem, but it's worth noting that you won't be able to push the SkyTracker Pro much more beyond its capacity. Choose your lenses wisely!
Meanwhile, alignment is via a precision polarscope with an impressive eight brightness levels, as well as a smartphone app (iOptron Polar Scope for iOS and Polar Finder for Android). The app needs to be purchased separately at an extra cost, but alignment is a breeze once installed on our iPhone. The SkyTracker Pro also runs quite quietly, although it does vibrate as expected – no slippage was encountered though and the exposures we took provided images with pin-sharp stars.
Something we discovered – and it’s important to note – is that both iOptron products use a platform that can’t handle motion time-lapses. Nevertheless, the SkyTracker offers four tracking rates; stars, 1/2 speed, lunar and solar, so you can also use it to photograph the Moon and even solar eclipses.
The Move Shoot Move Star Tracker isn't physically able to take lenses with a focal length of more than about 100mm – but we didn't see this as a massive problem, given that it's a standout tracker for those heading to a dark-sky area to shoot wide-angle images of the Milky Way as star fields. What's more, it's also small enough to fit in your pocket given its lightweight design. The overall build is of a pleasing quality.
Easy to use, and with accurate star-tracking, this little rotator offers super-easy polar alignment using a green laser – and, given the cost of the Move Shoot Move, we couldn't have asked for sharper images of the night sky. Especially before editing in astrophotography software.
The Move Shoot Move does have its downsides, however: it comes with a few fiddly screws that are easy to lose during imaging, while a poorly illuminated control panel makes it tricky to set up in daylight. The battery life is relatively short, made worse in colder conditions.
However, for entry-level astrophotographers, it’s the business – and kit prices start at just $258. As a bonus, the Move Shoot Move also works as a motion time-lapse platform in daylight, which landscape photographers will love. This star tracker is a good value, innovative, and nicely-sized addition to a camera bag: highly recommended to beginners!
Read more: Move Shoot Move 2-in-1 Star Tracker review
The Vixen Optics Polarie is designed to work with wide-angle lenses to image star-fields and the Milky Way. Featuring a built-in compass and latitude meter (which are helpfully illuminated in red light for set up at night), alignment is very straightforward – you'll need to locate the celestial pole through a sight hole or polarscope, with takes moments to achieve. There’s also a Vixen PF-L Assist phone app for iOS and Android.
Like the iOptron suite of products, the Polarie can track the stars, Sun and Moon, with a 1/2 speed for motion time-lapses at night. Meanwhile, the overall build is perhaps the best we've ever come across in the star tracker market – especially given the reasonable price tag and performance.
Similar to the Sky-Watcher model, the Polarie runs on two AA batteries – we discovered that the battery life doesn't last for very long, limiting us to no more than roughly two hours of valuable imaging time. However, the results we did get are superb with perfectly circular stars in our images.
To ensure no interruptions, we recommend powering the Polarie from a portable battery over micro USB, something that we did find to work best over switching batteries out throughout our session.
With the Polarie, the load is very limited at 2.5kg, but it is possible to upgrade kit with counterweights to a capacity of 6.5kg, making it possible to use with 200mm+ lenses. Just make sure that you have a tripod and mount that can take the weight of your setup!
The Sky-Watcher Star Adventurer Mini – as its name perhaps suggests – is one of the most portable star trackers on the market, given its small size. In fact, the Adventurer Mini is also one of the smartest star trackers around thanks to the utilization of smartphone technology.
The package is very similar to the iOptron SkyTracker Pro. With your smartphone already armed with the free Star Adventurer Mini Console app on Android or iPhone it’s possible to perform a polar alignment with the included polarscope and Polar Clock feature (which also allows you to change the speed for time-lapse modes). Alignment is a breeze, making it a suitable option for novice astrophotographers.
On first impressions, the overall build is of a very good quality, although the polarscope's illuminator could do with an upgrade. The scope's red light mode is effective in preserving night vision.
The platform itself has a built-in intervalometer, so if your DSLR doesn’t have one built in you can just attach it to the camera mount. Around 60-second exposures are achievable using a 100mm lens, though a counterweight is available that ups the load limit to 3kg. The images are very good, and we are impressed with the crystal clear results: we even managed to try a touch of deep-sky astrophotography with a fair outcome.
The Sky-Watcher Star Adventurer Mini can also perform motion time-lapses, plus it uses two AA batteries so it’s easy to refuel on the go. We recommend keeping your spares in your pocket – just to keep them warm enough for longer battery life – or use the micro USB port.
We are pleased to discover that the iOptron SkyGuider Pro can safely support a whopping 5kg, which means a zoom lens and even a (small) telescope can also be attached. As well as making deep-sky shots possible, it has four tracking rates; stars, Sun, Moon and, as a bonus, a 1/2 speed for motion time-lapses during the day or night.
This star tracker comes with a 1.35kg counterweight and has a built-in shutter triggering port so you don’t need to use an add-on intervalometer. In our experience, alignment using the SkyGuider Pro system – an electronic polar finder scope known as the iPolar – is painless. If you'd rather use your smartphone for the process though, there’s also an iOptron Polar Scope app for iOS and Polar Finder for Android, which also work well enough and get us from A to B.
The built-in rechargeable battery has a decent runtime (though you can also run it off a portable battery) and we enjoyed uninterrupted imaging. Results are very impressive, with good results of a selection of stars and galaxies, and the operation of the setup isn't too noisy.
Although it can support long zoom lenses during short exposures when at long focal lengths, only wide-angle lenses can stand five-minute exposures. The SkyGuider Pro is also not able to perform motion time-lapses: not a massive problem, given the excellent results achieved with this tracker.
Offering almost twice as much load as its ‘little brother’, the Sky-Watcher Star Adventurer Mini, this Pro version also ramps up the battery life by using four AA batteries that last for 72 hours. That’s plenty of time for a field trip into remote areas while also being simple enough to swap-out mid-shoot.
The original portable tracking mount that’s easy to set up (it uses a polarscope with Sky-Watcher’s free SynScan app for iOS and Android), the Pro is nevertheless a heavyweight in terms of design, meaning that it's not as portable as its competitors. That’s extended by the inclusion of a counterweight kit (a dovetail L-bracket and an equatorial wedge) for use with zoom lenses up to a focal length of about 400mm. Astrophotographers should make sure that they have a sturdy mount and tripod to support this star tracker.
The Adventurer Pro is able to track stars, Sun and Moon and also offers various motion time-lapse modes. It has a built-in intervalometer to attach a DSLR to, which makes this competent platform completely automated.
On the whole, this tracker is easy to use and operates quite flawlessly, allowing us to achieve pin-sharp results at a variety of exposures. The supplied manual is comprehensive enough, and we recommend giving this a thorough read before using the setup – it's very easy to fiddle with elements, which will take a while to put right.
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