Constellations

The very basic knowledge that every amateur astronomer has is to recognize the constellations above his/her head. No matter what you are looking for on the sky the constellations can guide you to find it. Think of them as a map, which you need to learn how to use in order to reach your destination. This is what we call stargazing.

Let start with a few words about some of the best-known asterisms, grouping them into Northern, Summer and Winter constellations. After that we’ll see how to photograph them. Stargazing cannot be taught. While I’ll do my best to give you hints and directions, you have to go out there and study the night sky.

star_trails

Trying to memorize the shapes and locations of all constellations at once is not necessary (nor even possible). Here is why. First of all, most of us won’t be able to see all constellations from the location where we live – unless you live on the equator. So try to learn those you can observe frequently. Second, some of the asterisms are very small, and you may not need them immediately to guide yourself on the sky. Last but not least, the best way to remember the constellations’ shapes and locations is by observing and only observing. Stargazing periodically is the only way of becoming familiar with the sky.

As I mentioned before, stargazing for beginners is not about knowing all the constellations, and so I’m not going to describe every single one of them. This is not the goal of this website and frankly, there is no need to. I’m sure you can find star chart (even a basic one will do) or you may already have one. With such chart in hands you can start learning and finding the basic constellations on the sky, and later you can try some others that are not as distinct or as large. Thus I’m going to mention only the most famous ones, even though you may have your own favorites.

Trying to memorize the shapes and locations of all constellations at once is not necessary (nor even possible). Here is why. First of all, most of us won’t be able to see all constellations from the location where we live – unless you live on the equator. So try to learn those you can observe frequently. Second, some of the asterisms are very small, and you may not need them immediately to guide yourself on the sky. Last but not least, the best way to remember the constellations’ shapes and locations is by observing and only observing.  Stargazing periodically is the only way of becoming familiar with the sky!

As I mentioned before, stargazing for beginners is not about knowing all the constellations, and so I’m not going to describe every single one of them. This is not the goal of this website and frankly, there is no need to. I’m sure you can find star chart (even a basic one will do) or you may already have one. With such chart in hands you can start learning and finding the basic constellations on the sky, and later you can try some others that are not as distinct or as large. Thus I’m going to mention only the most famous ones, even though you may have your own favorites.

Northern constellations

There are some that are visible throughout the entire year. Examples of such are The Big Bear and The Little Bear, Draco, Cassiopeia, etc. They are visible from most parts of the northern hemisphere. Read more about the northern constellations here.

Summer constellations

The summer sky presents us with the opportunity to observe a lot of interesting constellations. There are lots of interesting summer asterisms. Let’s start with the most famous one (which is not a constellation) – The Summer Triangle. It connects the stars Vega (constellation Lyra), Deneb (Cygnus “swan”) and Altair (Aquila “eagle”). All three stars are bright with apparent magnitudes ~0-1. Read more about the summer constellations here.

Winter constellations

The winter sky reveals us magnificent view, its crown, without a doubt, is the constellation Orion. Next to “The Hunter” are located the hunting dogs (Canis Major and Canis Minor), and the Bull (Taurus). Read more about the winter constellations here.

Photographing Constellation

As you know, all constellations have different sizes. To photograph the majority of the constellations you need lenses with focal lengths roughly between 24-135 mm (for 24×36 film equivalent). You need the longer focal lengths (80-135 mm) if you want to photograph smaller asterisms and if you want to have only one on your image. At these focal lengths you’ll need telescope to mount your camera on, or equivalent tracking device. ISO values of 100 to 400 will do the job.

The easiest way of taking photos of constellations is using tripod and a 35-50 mm lens. Set the lens at maximum aperture (lowest f-number) – see the next paragraph for more details. Then do 20 sec exposure. Longer exposure times will make your stars to look like short trails instead of points. If you use shorter lens you may be able to take 30 sec shot and still have the stars as points. For lenses longer than 80 mm, or even 50 mm, you’ll need a tracking device, or make exposures of several seconds only.

You can also leave your camera open for a few minutes. As a result, the stars will create small trails (like the photo above). You can increase the exposure time to half an hour or as long as you like. You can make really beautiful shots if you point your camera in the direction of the north celestial pole (Polaris) and let your camera open for a few hours. When taking pictures with exposure times of 10 min or longer, make sure that the lens’ f-number is not lower than 2! Do not forget that the sky is not entirely black and has some natural light. It’s called an airglow. So to reduce its effect, keep an eye on the lens settings. After all, we want the sky to look as dark as possible on our nice photos. Note: the location where you’re shooting from could affect the lower usable f-number. It’s best to make a few test shots, and given that we live in the digital era, you can review your results on the spot. The goal is to let as much light as possible (picking small f-number), but keeping the sky as dark as you can.

The good thing about shooting from tripod is that it’s easy to do and doesn’t require almost any equipment – just a camera and the tripod itself. However this technique has its downsides. Your photos will contain only the main, brightest stars (brighter than 3 or 4 magnitude). If you want to make photos rich of stars and/or one of those breathtaking images of the Milky Way, you will have to increase your exposure time to minutes. In this case you will need a tracking system.

Mounting your camera on a telescope, or piggyback astrophotography, is the best way to go. You can do exposures with any length – seconds, minutes or even hours. For best results use 5 to 20 min exposure times and set your f-number in such a way to avoid an airglow overexposure.

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