A Beginner’s Guide to Astrophotography
As its name says, astrophotography is the part of photography that concerns photographing astronomical objects and events. In my opinion, to call it astrophotography, intentionality has to play a big part in the photographic endeavour.
If it’s a photo of a random part of the night sky taken just for the sake of showing some points of light, then it’s not astrophotography. At least, not for me. However, if that photo shows a constellation, a group of constellations over a landscape, an astronomical event, a deep sky object, or a Solar System object etc. placed intentionally in the frame, then we are talking about astrophotography.
Astrophotography also has a documentary value, showing astronomical events as they happen. Pasting a Moon or a planetary grouping over a different part of the sky from where it was originally shot is also not astrophotography.
Photographing the sky when it’s fully dark outside but photographing the foreground at blue hour and merging everything in a spectacular image isn’t astrophotography either.
Don’t get me wrong. The resulting images can be extremely beautiful, but they are not astrophotography in the same way as a staged scene is not photojournalism.
Basic astrophotography equipment
You might have heard that astrophotography is an expensive hobby and you only need state-of-the-art gear to get fabulous images. That’s not entirely true.
You can start with the cheapest camera that offers manual control and still get very decent images. I will always advocate for getting the camera you can afford first and saving for an upgrade. I believe it’s better to have something to get you started than waiting for better days. After a few outings under the night sky, you might find out that astrophotography is not for you, and there’s nothing wrong with that.
To reiterate, you can start astrophotography with any camera that has a manual mode and manual focus, no matter if it’s a mirrorless or DSLR. It would be awesome if the camera has interchangeable lenses too, as this allows you to shoot a broader range of subjects.
If you can invest in a full-frame camera, go for it. Full-frame cameras will have better noise performance than smaller sensor cameras. A wonderful camera to start with is the Canon EOS 6D – the 6D Mark I, a camera launched 10 years ago, is still going strong for astrophotography.
If you want a new camera, absolutely any mirrorless camera that has interchangeable lenses is a good camera for astrophotography.
Even though a stock camera can be successfully used to photograph the night sky, I would suggest investing in a camera modified for astrophotography, especially if you want to do deep-sky photography. You can either buy a stock camera and send it to be modified by a third party (like Hutech) or get a camera built specifically for astrophotography, like the Canon Ra.
In terms of lenses, all focal lengths can be used in astrophotography, from fisheyes to super-telephotos. As most of the targets are very dim, you need lenses with a low f-stop (2.8 or lower).
My favourite lens for landscape astrophotography is the Sigma 24mm f/1.4 Art.
A very important piece of gear is the tripod. Get the best you can afford and keep in mind that cheap tripods will usually be flimsy. Any head will do, no matter if it’s a ball head or a three-way; it just needs to be sturdy.
You also need a cable release, and you can find wireless versions of such remotes but I wouldn’t recommend those. They need batteries to run so you have one more element that can fail during your astrophotography session.
Also, add some extra batteries and memory cards to your bag and you are ready to go.
Read more: The Best Lenses for Astrophotography
When and where to go
First, check the weather. If it’s raining or it’s cloudy don’t go out to do astrophotography – we need clear skies! Unless you want to take photos of the Moon, go out when the Moon is close to the phase of the New Moon; let’s say +/- 5 days around the New Moon.
To stay updated with astronomical phenomena like meteor showers, eclipses, conjunctions, and the activity of the Aurora, I recommend you check spaceweather.com at least every other day.
Even though great astrophotos can be taken from the city, it’s much better to photograph the night sky from a dark location far from light pollution. The sky will be totally different. Don’t forget to pack some extra clothes as it will be colder than you expect; even in the summertime.
Set-up and camera settings
Astrophotography is quite vast and every branch of astrophotography has its own specifics. Let’s quickly go through different kinds of astrophotography, and the basic camera setup and settings needed for that. Please have in mind that you should always adapt to the conditions you’re shooting in.
The following will only be some basic guidelines that leave a lot of room for experimentation.
One thing will be the same: focusing. To focus, set your camera to Live View, open the aperture to the max, and pump up the ISO. Rotate the focusing ring to its infinity mark. Find a brighter star on the display of your camera, magnify the live view image as much as you are allowed by your camera, and carefully fine-tune your focus until the stars look their sharpest.
Then, use some gaffer tape and carefully tape down both your focusing ring and zoom ring (if you use a zoom lens). This way, you can be sure that you won’t accidentally change the position of the rings. You should check focus from time to time as changes in ambient temperature might shift it a bit.
Of course, you always shoot RAW.
Read more: 7 Astrophotography Mistakes to Avoid
The easiest way to shoot star trails is to take many photos one after the other with no break between them, and then combine those into a single image using software.
Use wide-angle lenses (8-24mm) so that you can also include some foreground in the frame. Photographs of star trails that don’t show any landscape are quite dull.
When shooting star trails you don’t necessarily need bright lenses. You can easily shoot beautiful star trails with a lens that only opens to 4 or even 5.6. There’s one thing you need to be very careful of: don’t overexpose brighter stars so that they lose their colour. You will end up with only white star trails.
Read more: How to Shoot and Process Star Trails
A very broad category in astrophotography; it involves shooting the night sky above a beautiful landscape. This is probably the field that most people start with in astrophotography. You can create fantastic images of the Milky Way above breathtaking landscapes, but don’t limit yourself to that.
There’s more than the Milky Way in the night sky. Photographs of prominent constellations above different landmarks are equally beautiful.
You will need wide-angle lenses for this (8-24mm). Shoot wide open, or close the aperture by one stop to minimise lens aberrations. The most challenging thing is to photograph stars as points of light, not as trails.
You might have heard of the “500 rule” that helps determine the longest exposure time that allows stars to still render as points for a certain focal length.
Use the 300 (or even 250) rule. The “rule” states that your exposure time will be equal to 300 divided by the focal length of your lens. Thus, if you have a 20mm lens, the exposure time will be 300/20 = 15 seconds. The 500 rule was useful in the past but with modern cameras, it is a bit obsolete.
If you’re using a cropped sensor camera, you need to divide the previous result by the crop factor of your camera. To get even better at judging the exposure in your astrophotos, I strongly recommend reading my article on using the histogram in astrophotography.
Don’t forget the rules of composition in order to get an aesthetically pleasing photograph.
Conjunctions are apparent gatherings of Solar System objects in the same area of the sky. You can get beautiful, close conjunctions between two or more planets, or planets and the Moon.
You can approach conjunctions from two angles. On one hand, you can use wide-angle lenses (16 to 24mm) for not very tight groupings or for shooting multiple planets along the ecliptic. Choose a beautiful landscape and you are in for a great photo.
On the other hand, you can shoot conjunctions using longer focal lengths, especially when conjunctions are very close. Depending on the angular separation between planets, you can even use telescopes for this.
Conjunctions are more beautiful when they happen low on the horizon and during twilight. You need a low (100-400) ISO and an aperture of around 4. Play with the exposure time until you are happy with your image.
Some time ago, I wrote an article on lunar photography. You can find it here. Alongside lots of tips on photographing the Moon, you will also find more information about how to photograph conjunctions.
Meteor showers happen a few times a year. The more interesting to photograph are the active ones, like the Perseids (peak around August 12) and the Geminids (peak around December 14).
Meteors are visible for a very short time and are not always very bright. That’s why you need the fastest lenses you can get (faster than 2.8). Determine your exposure time as explained in the section on astro landscapes above. Start shooting frame after frame (an intervalometer could be helpful) until you are lucky and a meteor crosses your field. Be patient. It might take a while.
All meteors in a meteor shower, if traced back, will lead to a single point in the sky, called the radiant. To maximise your chances of photographing a meteor, don’t shoot towards the radiant.
How to photograph the aurora
Aurora displays cover vast areas of the sky. That’s why you need wide and super wide-angle lenses to photograph this wonderful phenomenon. I would suggest lenses between 14 and 24 mm, and even fisheyes for Aurora storms.
Use lenses with low f-stops, F/4 can be used with some limitations. It’s why I recommend lenses that open at least 2.8 for Aurora work. No two displays are the same, and it’s pretty much impossible to use the same settings every time you photograph the Northern or Southern Lights.
Sometimes the auroral curtains move very slowly and you can use long exposure times of up to 30 seconds. Though during very active displays, the Aurora will move super fast and you need very short exposure times, below 3 seconds if possible. Open the aperture to the max or close it by one stop if you have a lens that shows distracting aberration in the corners.
Good luck with the weather!
Of all astronomical events, total solar eclipses are probably the most spectacular. During a total solar eclipse the Earth, Moon, and Sun are so perfectly aligned that the Moon passes right between the Sun and our planet. Besides solar eclipses, we also have lunar eclipses, when the Moon gets inside the shadow of the Earth and changes its colour to a specific hue of deep red.
You can photograph eclipses using both wide-angle lenses and telescopes, depending on your goal. If you want to show the colour of the sky during a total solar eclipse use a wide-angle lens and frame some beautiful foregrounds. Start with these settings: ISO 100, aperture 5.6 and exposure time of 1 second.
Partial phases are not super interesting when shot at a wide angle and you will need a telescope or a lens of at least 500mm for that. Don’t forget to use a solar filter when shooting the partial phases of a solar eclipse or when shooting the full disc of the Sun during a normal day, when there’s no eclipse going on.
When shooting the total phase of a solar eclipse using a telephoto lens or a telescope, set an ISO of 200 and use all shutter speeds available on your camera. A single exposure will not be able to capture the grandeur of the solar corona. Automation is very helpful here, and I recommend checking software like Solar Eclipse Maestro. When totality ends, don’t forget to place the solar filter back in front of your lens.
Read more: How to Photograph Solar Eclipses
Deep sky photography
For all the above-mentioned types of astrophotography, you don’t need to follow the apparent motion of the sky as you only use short exposures. For deep sky photography, everything changes.
You need longer exposures and a fixed camera won’t do it. That’s why you need an equatorial mount – the device that allows you to track the stars. For just a camera and lens you can use a lightweight star tracker like the Sky-Watcher Star Adventurer or the Fornax Mounts LighTrack II. If you want to shoot through a telescope you need a sturdier mount.
When doing deep sky photography, you should take calibration frames – dark frames, bias frames, and flat frames – as well as photos showing the object you are photographing, known as light frames. Calibration frames are a set of images used to improve the signal-to-noise ratio in your light frames.
Also, for a better signal-to-noise ratio, you should shoot multiple exposures (light frames) of the same object whilst maintaining the same framing. All these images will be calibrated then aligned and stacked in a final image.
Deep sky photography is such a vast domain that entire books can be written on it.
Read more: A Beginner’s Guide to Deep Sky Photography
The final step: Basic post-processing
The last task is to edit your images, and the most important piece of advice when it comes to post-processing astrophotography is: don’t overdo it! I do minimal processing to all but my deep sky images (deep sky post-processing is a story for another article, I’m afraid).
I do most of the work in Lightroom or Adobe Camera Raw, first, setting the white balance. What’s the right white balance? Easy – there’s no such thing.
The colour of the night sky will be influenced by lots of factors. Play with the Temperature and Tint sliders until you are happy with the result. Just don’t set the white balance to Tungsten as many so-called astrophotographers recommend. You will end up with an image that is far too blue. Also, try not to end up with a purple Milky Way or a purple sky.
Pay extra attention when playing with clarity. It’s very easy to go overboard with this and images will start looking artificial pretty quickly.
Astrophotography has so much to offer the beginner photographer, and once you get started, you may find yourself hooked.
Clear skies, as we say!