Astrophotography is the science and art of photographing space and all its treasures. From the beautiful images found in astronomy magazines, to amateur shots using nothing more than a camera or smartphone, this wonderful hobby comes in all shapes and sizes. No longer just for pros, astrophotography has grown to be more accessible – and more important – than ever before.
The History of Astrophotography
The subject of the very first photograph of an astronomical body was the Moon. Louis Jacques Mande Daguerre was the inventor of the daguerreotype process; the first publically available photographic process. Daguerre attempted to photograph the Moon in 1839, but the resultant image was indistinct and blurry due mainly to tracking errors. A year later, John William Draper, a Professor of Chemistry at the New York University, took the first successful photograph of the Moon.
It is possible that the first attempt at photographing the Sun was in 1845 by the French physicists Leon Foucault and Hippolyte Fizeau. The Italian physicist Gian Alessandro Majocchi also tried (but failed) to photograph a total Solar eclipse in 1842 in Milan.
One true photographic achievement of the time was that of Her Majesty’s Astronomer at the Cape, David Gill. He photographed the Great Comet of 1882 in Cape Town, South Africa – and it was a mark of astrophotography’s true potential which has stood the test of time.
The Evolution and Importance of Astrophotography
Today, the photographs we have of the night sky and the Universe are astounding. Astrophotography has brought the surfaces of the planets and moons to Earth. We have captured supernovae and the oldest known galaxies. We have seen into the lives of stellar nurseries and watched galaxies collide. We have all this and more on film forever; speaking volumes to the place astrophotography has in science.
Consider the Hubble Space Telescope. It is by no means the biggest or even the most sophisticated telescope ever built. Despite this, it does have one great edge over every other telescope or camera ever made: it is free of Earth’s atmosphere. Molecules and shifting air pockets distort the light of distant objects (even if only slightly) as they enter the atmosphere, causing a twinkling called scintillation. No ground based telescope or camera can beat this effect. Thanks to the fact that the telescope orbits 569 kilometres above the Earth’s surface, the light of the objects Hubble observes and captures is undisturbed by Earth’s atmosphere. (As a side note, Hubble’s space location is also perfect for observing objects such as supernova stars and black holes in other wavelengths including gamma ray, X-ray and ultraviolet; most of which are absorbed by Earth’s atmosphere to protect life on the planet).
Hubble’s photographs do more than wow and inspire – they actually contribute to astronomy. In 1995, the telescope captured what is known as The Hubble Deep Field image. Hubble’s camera was aimed at a tiny fraction of the sky (24 millionth of the sky) in the region of the Northern constellation Ursa Major.
The image is composed of 342 separate exposures taken over 10 consecutive days using the Wide Field and Planetary Camera 2. The resultant image was mind blowing. That minute portion of the sky revealed some 3000 objects, the vast majority of them being other galaxies. Better yet, some of the youngest and oldest galaxies known were captured in that image, providing valuable insight into understanding the early stages of the universe and the evolution of galaxies.
Another great accomplishment of the space telescope was capturing an exo-planet in visible light. This is no small feat. There are ways that scientists detect exo-planets, and visible light is rarely such a method. Exo-planets are incredibly tiny objects orbiting their host stars at vast distances from the Earth, and producing no light of their own. They are nearly impossible to see, but Hubble’s camera triumphed once again. The Exo-planet is Fomalhaut b, also known as Dagon. Though the achievement was announced in 2008, it was only officially confirmed in 2012.
Hubble isn’t alone in the game either. Think of all the space probes which have photographed the surfaces of the Moon, Mercury, Venus and Mars. Of course, there is the legendary Voyager 1 space probe which has now left the Solar System; journeying where no man-made object has ever gone before. On the 14th of February 1990, Voyager 1 took an extraordinary photo – possibly the most important in all astrophotography – before it went beyond the reaches of the outer planets. Thanks to the much loved late astronomer Carl Sagan, the probe’s camera was turned back one last time to capture Earth from 6 billion kilometres away. The photo was dubbed Pale Blue Dot, and inspired a beautiful sentiment from Sagan regarding our humanity.
While the images that contribute most to science are usually taken by expensive and sophisticated instruments, the amateur’s contribution is not to be overlooked. Yes, most amateur photographs are taken for the pleasure of it all, but there have been a few records of hobbyist photographs being scientifically significant.
Anthony Wesley, an amateur astronomer in Australia, recorded impacts on Jupiter. Robert Evans, a minister and amateur astronomer (and also from Australia), made several supernovae discoveries from his photographs, and holds the record for discovering the most supernovae visually (42!).
Amateur astrophotographers also contribute by capturing events that stationary sites cannot. Meteor showers, eclipses, and aurora often occur in remote places that scientists do not always have access to, but which locals can film and photograph at the drop of a hat.
Basic Set Up: All You Need to Be an Astrophotographer
Having a good idea of the type of astrophotography you want to do is ideal before you purchase any equipment. Not only will this affect the type of equipment and set up you need, but also the amount of money you spend, the techniques and tips you will apply, and even the subjects you will photograph in the night sky. All these factors can be dependent on the branch of astrophotography you choose to explore.
Consider these general types of astrophotography techniques:
- Fixed/ Tripod Astrophotography: This is the most basic form of astrophotography and a great starting place if you are coming into the field with no prior knowledge or experience. It is also ideal because the setup is cost effective and simple. All you need is an entry level camera, preferably DSLR, and a way to fix your camera – a tripod is most effective.
The exposures are generally short unless you want to photograph star trails, in which case you can go for longer exposures and even longer focal lengths with your camera’s lenses. This type of photography is often referred to as landscape astrophotography, as popular subjects include constellations, the Milky Way, planetary alignments, the Moon, comets and meteor showers set against the beautiful backdrop of nature.
- Astrophotography Using Tracking Mounts: This is very much the same as fixed/ tripod astrophotography, except that your mount will now be able to track the sky. This means you can get the same shots using longer exposures without blurring, as the tracking mounts compensate for Earth’s rotation.
- Piggyback Astrophotography: As the name suggests, your camera or lens simply rides the back of your telescope! By attaching your camera or lens to a telescope which is equatorially mounted, you get to photograph the night sky at longer exposures and using longer focal lengths, while the field of view is kept centred by the telescope.
- Telescope Focal Plane Astrophotography: In this technique, the telescope itself is used as the ‘lens’, gathering the light for the film or CCD of the camera. This means higher magnification and better light gathering capacity. This translates into images of unparalleled clarity, detail and depth. This is also the hardest form of astrophotography because you are dealing with potential tracking errors, the difficulties of focusing dim objects in a narrow field of view, and magnified vibrations. That is not to even to mention the costs of added necessary components such as mounts, auto-guides, illuminated cross hairs and the likes. The allure is that the results – when right – can be so breath-taking they will be second to none.
Learning about the science of astronomy itself adds an extra level of depth to your astrophotography hobby, but what is even more important is understanding the basics of photography all on its own. A great photographer with zero knowledge in astronomy is always going to take better photos than an astronomy enthusiast with no knowledge of photography.
Photography is a broad field that requires skill, artistry, patience, and a great deal of knowledge and experience to master. Studying up as much as you can on the principals of photography is essential to mastering the hobby, but do not let complicated theory stop you from just setting up your camera and learning as you go. Nothing can replace the practical aspects of this discipline.
Equipment and Setup
One of the crucial elements that make or break astrophotography is the equipment you use. Purchasing the wrong gear can be a costly mistake! As mentioned, the equipment you will need differs depending on the type of astrophotography you choose to do, but includes:
- DSLR camera: You don’t need anything too fancy as a beginner. In fact, if you are coming from a place of no photography background, then going second hand is a fantastic option. One of the most important things to consider in a DSLR is its sensor size. The bigger the sensor, the more light your camera can collect. This is a must in low light conditions. It also means clarity and detailed photographs. You want to look for a DSLR that is ‘full frame’ – the maximum sensor size (36 x 24 mm) rather than ‘crop frames’ which are smaller. Contrary to what marketing ploys suggest, megapixels are not the most important feature in a camera. Any halfway decent DSLR will always have sufficient megapixels, so don’t fall into that trap. You want to be assured of other more important qualities like a long battery life, lots of storage space, and features like image stabilisation. You can see this guide for more information on choosing the best DSLR for astrophotography.
- Lenses: DSLR purchases sometimes come with stock lenses which, honestly, are not the always greatest. I recommend purchasing the camera body and lenses separately so that you are getting the best value for money on both.
- Mount/ tripod: If your ultimate goal is to do astrophotography using your telescope, or even long exposures with your camera, a tracking mount like an equatorial mount for a telescope is the only way to go. This type of mount is polar aligned, meaning it is set to follow the rotation of the Earth. If you take a look at long exposures of the sky taken from a fixed position – like a camera mounted to a tripod – you will notice that the stars form a ghostly trail. If you do not want such a trail, your telescope/ camera needs to move with the stars. Tracking mounts accomplish this.
For a camera tripod, nothing fancy is needed at all – the only criteria it should meet is that it is stable.
- Telescopes: If you are interested in piggyback or telescope focal plane astrophotography then of course you need a telescope. There are a dozen pros and cons to different telescopes. Refractors are easy to maintain, do not need their optics aligned, and usually come with equatorial mounts. They are however more expensive and generally smaller in aperture. Reflectors or Newtonians are more affordable and come in nice, large apertures. On the downside, if they are too big an equatorial mount will not effectively work. They also require some up-keep. For beginner stargazing and astrophotography, a small refractor is everything you need. Ultimately, the telescope’s mount is far more important to astrophotography than whether you have a refractor or reflector.
- T-mount adaptors: T-mount adaptors connect your camera to your telescope. T-mounts are made according to the brand of DSLR you are using. Instead of using a camera lens, you attach the T-mount to the camera’s body and then insert into the focuser of your telescope.
- Software and Apps: In many ways, astrophotography is the main indication of how far software and apps have come in the fields of science, photography and even art. Take advantage of the benefits, convenience and efficiency of astrophotography software (especially freeware!) and apps which assist you with image capturing, processing, plugins and filters, planning imaging sessions and even polar aligning your telescope.
Astrophotography is possibility the most relatable and personal branch of astronomy. It shows the progress of our technology, perfectly defines our fascination and relationship with our place in the cosmos, and captures unique moments in space and time. There is nothing more thrilling than picking up your camera and being well on your way to having a collection of astronomy photos you can call your own.