After a summer spent with the Sky Watcher Star Adventurer, Drew Buckley offers his experienced opinion of how it fares in the field
In part one of the Sky-Watcher Star Adventurer review, I covered the astro tracker functions, what comes in the box with it, what it’s capable of and how to set the tracker up using certain stars to calibrate it ready for photography.
Now I’ve had some more time with it over the summer, here’s a roundup of my findings and a little walkthrough of what goes into processing some of the images captured with the Star Adventurer.
The key thing to remember with night sky photography is that your goal is to capture as much light as possible in the given exposure time. The longer you can allow light to flood into the camera, the more information (i.e. stars/nebulae) you will capture. The problem is that the night sky moves, and a static long-exposure shot of the stars will render them as smears across the sky. Now, with this small and portable piece of equipment that will track the movement of the stars in the night sky, exposing the camera for several minutes per shot is now possible – even longer sometimes, depending on how accurate the calibration is! This for me is a real game-changer for my night sky photography and a very valuable part of my photographic arsenal.
Tripod vs Tracker
Below we have roughly the same composition of the night sky on a stretch of my local coast. They’ve both been photographed using my Canon EOS 5D Mark III and the Samyang 14mm f/2.8 lens (my favourite combo for night sky photography). They have also been processed the same in Lightroom, with the same sharpening and any noise reduction settings equally. The first image is taken with a ball head on top of a tripod, and the second is taken using the Sky-Watcher Star Adventurer mounted on the same tripod and the camera connected to it via the same ball head.
This first image’s settings are f/2.8, 30sec, ISO 4000.
I adjust my ISO settings depending on the location and how good the visibility is. The settings above are usually what I use for my night-sky images, allowing enough light in the exposure time before any star trailing becomes apparent. The maximum exposure time you can use when photographing with just using a tripod, while keeping stars properly sharp, depends on the equipment you’re using, as well as the angle of the stars to the Earth. You can use this handy calculatorto work this out for yourself.
This second image’s settings are f/2.8, 211sec, ISO 2000, and the shot was captured using a correctly calibrated Sky-Watcher Star Adventurer.
Without even knowing the settings of each image, you can instantly tell the second image is a much cleaner shot in regards to visible noise. It has loads more detail in the sky and the stars, and has captured more nebula and dust-cloud information. This is all down to how long the shutter has been letting in light for; the longer the exposure, the more hidden detail in the night sky is rendered onto the sensor.
One downside to using the Sky-Watcher Star Adventurer is the visible movement and blurring of the foreground landscape. This unfortunately is unavoidable, as the Star Adventurer follows the stars.
It’s probably best to avoid using the Star Adventurer for an image where there is a strong foreground element, as it will be rendered blurred against the sharper starry skies, severely so if your exposure time is especially long.
If you want to use the Star Adventurer for an image with a strong foreground element, your best bet is one where the foreground element doesn’t encroach on the sky space. In this situation you would take two images – one of the foreground, static, and the other using the Star Adventurer to capture the best of the sky. This done, make a composite of the two using Photoshop or your image editing program of choice.
Even though iconic or unique landmarks feature heavily in the foreground of my normal astro photographs, there’s still fun to be had without any landscape at all! Excluding the landscape from the frame gives you more freedom in terms of where to point your lens using the Star Adventurer. Selecting certain areas – honing in on constellations, nebulae or galaxies – will produce much more detailed images. The below image has become one of my new favourite night-sky images and was made possible thanks to this little tracker.
Using my Canon EOS 5D Mark III and an EF 24-70mm f/2.8L USM II lens, I zoomed in to around 50mm and focused purely on the main core of the Milky Way. Choosing an ISO of 1250 and a shutter speed of just over five minutes, I set the shutter going with my cable release and waited.
One tip: when you want to expose images longer than the preset camera maximum of 30 seconds, you’ll need to use a cable release with a lockable shutter and also switch your camera to bulb mode. So, as long as the cable release shutter is activated and locked in, the shutter will remain open. It’s just a case then of checking the elapsed time on the camera screen, and stopping the exposure when you want.
What was captured in the above totally blew me away. I’ve seen what long exposures can capture of the night sky, but coupled with the tracker it just looked incredible. In this small area of the sky there are so many nebulae that aren’t visible to the naked eye – these are the pinky purple areas, featuring the Eagle, Lagoon, Swan and Trifid Nebulae to name but a few. Also just the sheer amount of colouration and shape in the dust clouds is simply amazing. My camera and lens are pretty much standard equipment, so the simple addition of the tracker enabling me to capture these kind of detailed images is truly mind blowing. As with all RAW images, they don’t come out of the camera looking like the above. This is even more true in the case of night-sky images: they always need a bit of punch and enhancement due to atmospheric conditions and any light pollution affecting the sharpness and true colours of the sky. Here is the before and after in Lightroom:
Looks quite drastic at first, but you can see it’s all there on the original RAW file and there’s lots of detail waiting to be extracted. The main thing I always find with night-sky images are that they usually appear quite washed out as RAWs – this can be due to haze in the sky, light pollution or thin clouds that are not visible to the naked eye at the time of taking the photo.
Thankfully there are a few handy tools in Lightroom to counteract this effect, the main one being Dehaze. Using this can really cut through the crud and show the stars off at their best. From here it’s a case of upping the contrast, clarity and pushing the blacks down and whites up. All in all, we’re looking to creating a decent histogram without going to the extremes and making the image look unnatural. A small vibrance boost is always needed on RAW files, and it’ll also enhance the natural colouring found in the nebula and galaxy dust clouds. In this case, some sharpening and a tiny amount of noise reduction were needed for the final file.
Just as I was finishing this image (above), I noticed the International Space Station (ISS) appearing in the sky so I quickly zoomed out, recomposed and exposed for another five minutes. This rendered the movement of the ISS as a streak of light, appearing to travel into the core of the Milky Way.
Using a longer lens, I zoomed into the Andromeda galaxy. The Andromeda Galaxy (M31) is the closest large galaxy to our own, and is one of a few galaxies that can be seen with the naked eye, although you get a better view with binoculars or indeed a 200mm lens.
It’s worth noting that with the Star Adventurer, the longer lens you use, the heavier the load on the gearing. Also, the more accurate you have to be with your initial calibration as you’re looking at a much narrower field of view than with a wider angled lens so in these instances, make sure everything is spot on before commencing photography.
With these kind of subjects (deep space objects), the common way of photographing them is to take many images of the same scene, using the same settings and stacking these images on top of each other to get more detail in them, using specific stacking software. However this photograph is just one image, with an exposure time of just over two minutes. It still shows plentiful detail in the stars and colouring of the dust clouds around the galaxy, and using similar processing techniques as mentioned above, additional information has been extracted from the RAW file.
Having had the opportunity to play around with this Star Adventurer further has been an extremely enjoyable experience. Not only did it consistently, accurately and effortlessly track the stars, even with a heavy large lens on, but it also proved eminently portable, didn’t take up much room in the bag, and delivered results that really indicate that it’s a very powerful piece of equipment. The possibilities are endless, and for anyone who shoots night sky photography, it should definitely be in the kit bag!