Introduction to photographing the night sky

Astrophotography is considered to be a perfect fusion of science and art. This genre of photography allows us to capture the beauty of the cosmos through a camera and a lens. The celestial objects, including stars, planets, galaxies, nebulae, and many more, are transformed into visual masterpieces through astrophotography. It opens up a window to the universe – from the arc of the Milky Way, intricate details of a nebula, mesmerizing craters of the moon, you have it all.

This guide will explore what astrophotography is, its history, the subgenres of astrophotography, and the unique amalgamation of science and art that makes it captivating.

What is astrophotography?

Astrophotography involves the practice of photographing astronomical objects and phenomena. It focuses on celestial objects far away and often invisible to the naked eye. This is one of the things (out of many) that distinguishes it from other types of daytime photography. While most types of photography involve objects that can be seen and composed, most objects captured through astrophotography remain invisible to the naked eye and come into visibility after a long exposure through the camera. The faint photons, travelling hundreds and thousands of light years, are gathered in the camera sensor. Astrophotography involves some specialized techniques to enhance the details of these objects.

Astrophotography, along with creating beautiful images, is also used as an essential tool for scientific discovery. Professional astronomers take pictures of the night sky, map constellations, observe planetary movements, and explore galaxies billions of light years away. Astrophotography can be perceived as a combination of technical and scientific knowledge and artistic vision, resulting in a stunning representation of the night sky.

A brief history of astrophotography

The beginning of astrophotography can be traced back to the mid-19^th century. John William Draper took the first photograph of the moon using a daguerreotype, a photographic process involving silver plates, in 1840. This photograph seems to have paved the way for the exploration of the cosmos through photography. In the late 19^th century, technological advancement gave astronomers the opportunity to photograph star fields and nebulae. One of the most iconic images of the Andromeda galaxy was captured in 1888, revealing some of its intricate details. Issac Roberts captured this image using a 20-inch reflector. The evolution of astrophotography as a powerful scientific tool could be observed in the 20th century. Usage of specialized cameras and powerful telescopes were used to document celestial objects and phenomena. It led to many important scientific discoveries, including the expansion of the universe.

With the advancement of photographic technology, astrophotography has become more accessible to amateurs in the modern era. Powerful digital cameras, user-friendly software and affordable equipment have given amateurs a chance to capture the beauty of the universe from their backyard or terrace. Things that were achievable only through professional observatories with large telescopes can now be done from your home.

Types of astrophotography

Depending on the kind of equipment used and the kind of celestial objects or phenomena being photographed, astrophotography can be divided into many subcategories or subgenres. Each of these subcategories caters to different skill levels and interests.

Wide-field astrophotography (Nightscape, Deepscape)

As the name suggests, wide-field astrophotography involves photographing a large section of the night sky. One can use a wide-field lens (8 mm up to 200 mm) to capture the Milky Way, constellations, star trails or meteor showers. Wide-field astrophotography often involves a combination of landscape elements and sky elements, together forming what is known as “nightscape” or “Astro-landscape” photography. An advanced technique within this subcategory can also involve using a mid-sized telephoto lens (100-200 mm) sitting on top of a motorized tracker. This can capture some deep sky objects along with landscape elements, known as “deepscape” photography. With requiring only a camera, lens and tripod, this type of astrophotography is the most beginner- and budget-friendly.

Deep sky astrophotography

Deep sky astrophotography focuses on capturing the faint and distant nebulae, galaxies, and star clusters. It involves advanced techniques and advanced equipment like dedicated astronomy cameras, telescopes and equatorial mounts. Although photographing deep sky objects may not be considered beginner-friendly, DSLR or mirrorless cameras attached to a telephoto lens or a small refractor telescope can capture the faint light coming from these far-lying objects.

Lunar and Planetary photography

By using a reflector, large refractor and other types of telescopes, one can capture close-up photographs of the moon and its surface details. It also involves capturing images of the planets. A dedicated astronomy camera with a smaller sensor and fast fps rate is mostly used for lunar and planetary photography. Similar to deep sky photography, planetary photography also involves the usage of advanced equipment and techniques and requires advanced skill levels. However, a DSLR or a mirrorless camera attached to a telephoto lens (600 mm, etc.) can capture fantastic details of the moon. It can also reveal some features of the planets, including Saturn’s ring and Jupiter’s great red spot.

Solar photography

Solar photography involves photographing the sun during an eclipse or on other occasions. It mandates the use of a dedicated solar filter, as simple as a white-light filter. The equipment and techniques involved are very similar to that of lunar and planetary photography. The revelation of the dynamic nature of the solar surface, its sunspots, filaments and prominences creates the essence of solar photography. Using dedicated narrowband solar filters like Hydrogen-alpha filters reveals, intricate details of the solar surface and atmosphere. A DSLR or mirrorless camera, attached to a telephoto lens and solar filter can also give amazing images of the sun.

Optical phenomena photography

Although optical phenomena do not strictly adhere to the criteria of other subcategories of astrophotography, they can still be considered an essential part of astrophotography. It involves photographing the colourful and mesmerizing phenomena created on our earth’s atmosphere by reflection/refraction/diffraction of sunlight or moonlight. Rainbows, halos, corona, and arcs are all parts of photographing optical phenomena. The techniques and equipment required for photographing these phenomena are similar to that of wide-field photography, requiring a camera, lens and tripod.

Each subcategory of astrophotography reveals different beauties of our cosmos and comes with its own required skills and challenges. And these challenges are what make astrophotography a journey of learning and revelation.

Overview of equipment for astrophotography

While astrophotography often requires specialized equipment like dedicated astronomy cameras, telescopes and equatorial mounts, one doesn’t need to invest right away to start doing astrophotography. A basic camera or even a smartphone can engage you with this beautiful passion.

Camera

A great starting point will be a DSLR or a mirrorless camera. These cameras allow you to have complete manual control over the exposure triangle parameters: shutter speed, aperture, and ISO. Having control over these three is essential as they allow you to take good images and long exposures. Your camera should also have the ability to shoot in RAW mode, which will allow you to work with your data without losing any details. Smartphones these days offer a great starting point for astrophotography. Their low-light sensitivity, RAW shooting capabilities and manual control ticks all the boxes for astrophotography.

Lenses

With the option of shooting large chunks of the night sky to small galaxies, you will always have a subject to shoot with your lens. While wide-field lenses can be used for shooting the Milky Way, constellations, star trails, etc., mid-sized telephoto lenses can be used for photographing deepscapes, and long telephoto lenses can be used to photograph the nebulae, galaxies, the sun and the moon. Telescopes, instead of camera lenses, are also considered to be essential to astrophotography. Although there are no specific criteria for specific lenses, a fast lens (e.g. f/1.8 or f/2.8, etc.) and a lens with corner-to-corner sharpness are regarded as the best astrophotography lenses.

Tripod

One of the most essential criteria for astrophotography is to take long exposures. In order to achieve a long and sharp exposure, a tripod is a must. You will need a sturdy tripod that can support your camera, lens and other accessories.

Equatorial mount

Every object captured in astrophotography is on the move, from east to west. This happens due to Earth’s rotation from west to east. As mentioned earlier, we need to take long exposures to capture the faint details of the celestial objects. These motorized mounts that sit on top of your tripod carry your camera and lens and track the moving sky. These allow taking long exposures without introducing star trails. While EQ mounts come in different shapes and sizes, a portable star tracker is mostly used for wide-field astrophotography.

Accessories

Accessories like lens warmers, intervalometers, filters and power supplies are essential to astrophotography. A lens warmer attached at the front of the lens keeps the front objective lens free from dew. An intervalometer allows you to take long exposures and take multiple shots. Light pollution filters help you get rid of some of the skyglow introduced via city lights. Advanced astrophotography involves the usage of broadband (L, R, G, B) and narrowband (Ha, Sii, Oiii) filters to capture deep-sky objects. There are also many filters dedicated to capturing planets (e.g. IR Pass filter, etc.). A power supply ensures that your camera and other accessories never run out of power during a whole night’s session.

The science and art of astrophotography

Astrophotography involves the understanding of technical aspects of the camera (like any other genre of photography), but it also involves the knowledge and understanding of some of the astronomical objects being photographed. Before and after you photograph a nebula, you might want to know what a nebula is, what kind of gas is there, how far away it is and many other facts about it. Of course, one does not have to become an astronomer to do astrophotography, but a sound knowledge of the sky, the stars, the constellations, the deep sky objects, and the planets will definitely help one to become a better astrophotographer. As discussed before, astrophotography was developed by professional astronomers to aid scientific study. The end result, that is, the image can be seen as a resource of scientific knowledge.

Along with the scientific aspect, astrophotography inevitably involves photography, the artistic aspect. The compositions, the colours, the highlights and the shadows all give you creative freedom. Right from composing the image to adding the final touches during post-processing, the photographers’ artistic expression can be manifested. Astrophotography is a happy marriage of science and art.

Why astrophotography is gaining popularity

In the last few years, or maybe during the last couple of decades, people have started taking up astrophotography. One of the main reasons behind this surge is the advancement in camera technology and processing software and their accessibility. Astrophotography is no longer limited to the professionals. Smartphones and entry-level digital cameras have become capable of capturing faint lights coming from the stars. With the advent of the age of social media, Instagram, Facebook and other forums are helping to spread the word. These social media platforms have a thriving community of beginners and experienced photographers who share their interests and work with one another. It is also a great way to get feedback and hone your skills. For those who feel deeply connected either to photography or the night sky or together, astrophotography fosters their emotional connection. Standing under the stars in a dark location makes you one with the universe. It is always a humbling experience to realize that you are photographing photons that have travelled in both space and time to reach the camera sensor.

Astrophotography is a strong bridge between science and art and a wonderful hobby (or profession) to take up. For beginners, it offers ample opportunity to explore the night sky, develop technical skills, and express creativity. While in some cases, the learning curve might seem to be steep, the rewards, both visual and personal, are immeasurable. Whether you are unlocking the secrets of the universe from your backyard or finding yourself within the vast cosmos, astrophotography is an adventure that will last forever.