What if you could take incredible close-ups of wildlife, buildings and celestial objects through your telescope or spotting-scope? You can, and all you need is a smartphone
There are several ways of taking photographs through a telescope, which range from attaching a DSLR or mirrorless camera, to using webcam-like planetary cameras combined with complicated image-stacking. However, the easiest and simplest technique is to put your smartphone’s camera lens up to the eyepiece and compose a photo. Easy!
Known as afocal photography (if you use a telescope) and digiscoping (if you use a spotting-scope), it takes careful positioning of both telescope and smartphone, but done properly it’s an effective way of getting great photos. Here are some of our top tips to get you started…
1 Preparing your telescope and smartphone
The first thing to do is to set-up your telescope or spotting scope, whether that’s in your backyard or elsewhere. Make sure it’s stable, with screws tightened on the supports and around the telescope tube. Or make sure your spotting scope’s tripod set-up properly. Most telescopes have two eyepieces, one low-power (about 25mm) and one high-power (typically 8mm). The former is for finding an object, such as a bird, or the Moon, and getting it centred in the eyepiece. The latter is for getting a close-up.
If you’re using a computerized ‘go to’ telescope you’ll probably have to align it with a couple of bright stars before it can automatically ‘slew’ to an object.
You don’t need to do anything special to your smartphone, but bear in mind that you may have to contort your hands a little and hold the device in various unusual positions, which will increase the chances of you dropping it. So a drop-proof case is a wise idea, at least in theory. In practice that very same case may prevent you from getting a good photo, so it may have to be removed.
Why does your subject look backwards? Telescopes use an array of lenses and mirrors that usually result in the object you’re looking at seeing upside-down and/or inverted. That’s because they’re aimed at astronomical use where it’s mostly irrelevant.
2 Manually taking the shot
So-called afocal photography is not difficult, but it can take a little practice. Using a smartphone’s camera with a telescope is called afocal photography because the eyepiece on the telescope is essentially doing the work of enlarging the image.
All you have to do once you’ve got your target in the crosshairs of the telescope is to focus the image using the telescope’s focusing knob. Then position your smartphone camera’s sensor over the eyepiece, though take your time. You will have to shuffle it around before you find the exact position from where a full-screen image will be visible on your smartphone.
There are some techniques to help you get as sharp an image as possible. With the subject centred on your smartphone’s screen, tap the image of the object to bring it into perfect focus, then hold your finger down to lock the focus (thus disabling autofocus). Now just tap the shutter. A shutter a delay of a couple of seconds can make the process smoother and prevent vibrations that can blur the resulting image.
3 Shoot for the Moon
If you want to try some afocal astrophotography then there’s really only one game in town – the Moon. As by far the brightest object in the night sky, the Moon is an ideal target for afocal photography, and it’s easy to get a fabulous shot with almost any smartphone. Just line-up your smartphone’s camera with the eyepiece as before and touch the Moon on your smartphone’s screen to focus. Just remember that the final image may be upside-down or backwards, depending on what telescope you are using.
You may not notice it yourself, but a wrongly-orientated Moon will be very obvious to many people. So compare your shot to a photo of the Moon online and flip/invert yours using editing software such as Lightroom, Affinity Photo or Photoshop.
The Moon’s apparent position in the night sky changes very quickly when viewed through a telescope. It’s moving at 2,288 miles per hour as it orbits Earth and covers a distance approximately its own diameter each hour. Meanwhile, Earth is revolving at roughly 1,000 miles per hour. The result is that unless you have a ‘go to’ or tracking telescope you’ll have to re-centre your telescope on the Moon every few minutes.
4 Shoot in RAW
You can almost certainly use your smartphone’s built-in camera app to create usable and sharable images. However, most smartphones record images in the compressed JPEG format, so if your smartphone's own camera app doesn't include RAW then consider using third-party camera apps that do.
RAW formats are much easier to touch-up in photo editing software like Adobe Photoshop, Adobe Lightroom or Darkroom. Apps such as ProCam X, Halide and VSCO deal in RAW formats while also allowing you to use manual settings more easily.
If you’re shooting the Moon or trying for planets (Jupiter and its four giant moons are a good target) then you might see a lot of glare on your smartphone’s screen. You can fix this by lowering the exposure slider, though you can also consider using a ‘moon filter’ on your telescope that reduces glare and improve contrast.
5 Choosing and using a smartphone telescope adaptor
Although handheld afocal photography using a smartphone is relatively simple, it can be rather fiddly. You can reduce the need to precisely position (and constantly re-position) your smartphone on a telescope or spotting scope by buying a special adaptor.
These devices are rather like smartphone holders for cars, which clamp around the eyepiece holder. They allow you to precisely position your smartphone camera over the eyepiece, which cuts-out wobble. It also frees-up one of your hands and makes it much easier to dial-in manual settings on a smartphone’s camera app. However, try to avoid cheap products, which can be flimsy and make it difficult to accurately align the camera lens with the eyepiece.
The most reliable products come from optics brands such as iOptron, Celestron, Bresser and Orion, but be prepared to fiddle with a plethora of levers and clamps before you eventually get a snug fit around your smartphone.
As well as giving you wobble-free images, attaching a bracket to hold a smartphone camera automatically gives you a bright live-view feed from your telescope that’s easy to share with others. That can be especially handy if you’re out moon-gazing while our satellite is very high in the sky and the telescope is thus pointed almost straight-up.