WRITTEN BY LORIS FERRINI AND SILVIA POLITO
Step outside on a clear night, away from the glare of city lights, and look up at the sky. What do you see? The twinkling of stars, the faint glow of distant galaxies, perhaps even the shimmering trail of a passing comet. Now imagine being able to capture the majesty of these celestial wonders through the lens of your camera. Welcome to the fascinating world of astrophotography.
Astrophotography is more than just taking pictures of the night sky; it's a journey into the depths of the Cosmos. It presents unique challenges compared to traditional photography. Long exposures are often necessary to capture the faint light of distant objects, requiring stable mounting and tracking to prevent blurring. Patience is key, as capturing the perfect shot may require multiple attempts and adjustments.
In this article, I would like to give you a glimpse of astrophotography by starting with the closest celestial object we can see: the Moon.
Our natural satellite is easy to see with naked eyes, but have you ever tried to photograph it with your smartphones? All you get is a faint, indistinct and pale dot in the dark sky. Indeed, taking a good picture of the Moon can be very challenging. Let’s see how we can do that.
There are two options to photograph the Moon: shooting a full disk Moon, or shooting small sections of it in high resolution.
For the first type of photography, any type of reflex or mirrorless camera with a telephoto lens is fine; it is also possible to connect the "direct focus" camera body of a telescope to the camera (in this way, the telescope becomes the optics of the camera).
For the second type, we will instead photograph individual sections of the Moon: craters, seas, mountains and many other details present on the surface will be our subjects.
With the first type of photography, we will be able to photograph the Moon in its entirety, even in contexts set with a foreground. One of the best moments is when it rises or sets because, like the Sun at dawn and at sunset, it becomes reddish/orangish (this phenomenon is caused by the light passing through multiple layers of the atmosphere and turning towards red). Then, as it rises into the sky, it gets back to its greyish colour that we are used to seeing.
The full Moon, however, appears very flat and with little contrast because it is entirely illuminated by the Sun, and therefore loses any sense of three-dimensionality. For this reason, the best nights to photograph its full disk are when it is “in phase” (which is when we can see its different apparent shapes during its cycle), because the line between light and shadows (called ''terminator'') gives a strong contrast with plays of light and shadows, highlighting craters, mountains and flat expanses.
Despite this, there are a couple of very particular shots that can be taken of the full Moon (in addition to the suggestive moments during an eclipse). Like the Earth's orbit with respect to the Sun, that of the Moon with respect to us is also elliptical. This leads to a moment in which the Moon is at its closest point to us (perigee) and a point in which it is furthest from us (apogee). These are the so-called ''Supermoon'' and ''Minimoon'' that the media boasts so much about. Since we wouldn't be able to see the difference between these two full moons with the naked eye, photography comes to our aid: we can compare two shots of the Moon taken in the same conditions during these moments to better appreciate the apparent different size.
Another shot of the Moon is the so-called ''mineral Moon'', thanks to which we can see the true colours of the Moon. We usually see it greyish-white because it reflects so much light from the Sun that our eye cannot distinguish the colours, but a photographic sensor can. You have to think of the Moon as if it were a huge stone made up of many minerals and different materials, reflecting the light differently. By treating the photo, not as if it were a black and white shot, but as a normal colour shot, we can bring out the true colours of the lunar surface.
The other type of photos that can be taken of the Moon are those in high resolution; here, to obtain a final photo, we start from a video. This particular technique is called ''Lucky Imaging'' and it is used because, in order to take this type of photo, we use such high focal lengths (even over 3000mm focal length) that you can even see the air moving. This phenomenon is the same as when during a hot summer day you look at the street and you see patch of shimmering water on the road; in simple terms, what you just saw is a heat mirage. The same happens with the atmosphere, and it’s called “seeing” or “atmospheric turbulence”: air masses that move and degrade and disturb the image.
With this shooting technique it’s possible to eliminate the atmosphere between the lens and the subject. This is because a video at a high shooting speed will be recorded; the shooting speed is greater than the atmospheric turbulence, so as to counteract it. By ''high shooting speed'' we are talking about 150/200 frames per second, and this is why reflex or mirrorless cameras take a back seat (as they have very large sensor, large pixels and not so high shooting speeds) and are replaced with dedicated astronomical cameras for video recording (which have small sensors, small pixels and very high performance at high fps).
The processing program (Autostakkert) will consider every single frame of the video as a single photo, so a very large amount of frames is taken in a very short time! For example, if I shoot a 10 thousand frame video, it is as if I had taken 10 thousand photos; due to probability (or luck) I will have a certain percentage of frames in which my subject is perfectly still, frozen in that instant and not disturbed by the “seeing”. Those are exactly the frames that must be selected, added together and then processed (Astrosurface) to obtain the final result.
In this case, too, it is much better to take shots of areas close to the terminator line, to have much more contrast and three-dimensionality. It is also particularly interesting to shoot the same crater, but in two opposite phases, so as to have the shadow on both sides, compare the two shoots and see the differences that the lunar surface acquires.
An advanced technique consists in taking various shots of different areas of the Moon close to each other and then put them together as if they were pieces of a mosaic or a panorama. This allows achieving extremely higher details than a single shot of the same area.
Overall, astrophotography can be very challenging but also extremely fascinating and satisfying. In this article, I showed you how to take different pictures of the Moon and its surface. The techniques I described here are a good starting point for whoever wants to approach this magnificent type of photography. And once the Moon has been conquered, we can point further deep into space!
IN THE NEXT LINKS YOU CAN LEARN MORE ABOUT ME AND MY WORK:
WEBSITE: https://lorisferriniastrofoto.it/
ABOUT THE AUTHOR
Hi, I'm Loris, I mainly deal with astrophotography and daytime landscapes. My passion for astronomy began as a child when I was given my first telescope, then it remained with me and has grown to this day. I have been practicing night photography for 8 years now and I have tried to create a set of instruments that allow me to do every type of astrophotography: from the wide field of the Milky Way, to the deep sky of nebulae, long focal length for distant galaxies and high resolution images of Moon and planets. Instead, she is my collaborator
Silvia: Hi! I'm Silvia Polito, a linguist and financial translator working in English, French, and Italian. When I'm not working, you'll often find me gazing up at the stars, completely fascinated by astronomy and the universe. In fact, I'm about to enroll at University (again), this time for an astronomy course. I also work with the UAI, which stands for the 'Italian Amateur Astronomers Union'. I'm currently living in Forlì, Italy.
DO YOU WANT TO BE FEATURED IN OUR BLOG?
If you are passionate about photography and enjoy sharing your expertise with the community, our blog is for you. Go to https://www.theartistgallery.art/write-with-us read the rules, and submit your work.
Being featured in our blog will bring you several advantages, we will share your work not just in the blog but also in our social media and newsletter. You can talk about a photographic project you are working on, the story behind your best shot, your technical skills or just share tips with the community.