Cassiopeia - Widefield Astrophotography of the Queen of the Sky Constellation

Cassiopeia is one of the brightest and most recognizable constellations in the night sky. It is very easy to find thanks to its obvious "W" (or "M") shape, and contains several popular deep sky objects!

Cassiopeia is often used to star hop to the North Star, Polaris. The constellation stays visible high in the sky for most of the year, making its celestial objects popular targets for amateur astrophotographers.

I decided to image Cassiopeia on a very windy night that completely ruined all the shots from the main telescope setup. Luckily, I had brought my Canon mirrorless camera, a 135mm lens, and a second mount just in case!

I spent about three hours on it, although I had to delete several frames due to strong wind gusts, which brought down the total integration time.

3 hours on Cassiopeia with a Canon Ra.

GEAR USED:

Camera: Canon Ra

Lens: Samyang 135mm f/2 mounted on Astronetics

Mount: Sky-Watcher EQ6-R Pro

Processing: Pixinsight

ACQUISITION DETAILS:

Total Exposure Time: 3 hours

Exposure Time per frame: 3 minutes

ISO: 1600

Cassiopeia not outlined, click on the arrow for the outlines

Cassiopeia can easily be found in the sky for most of the year, although is peaks and stays at its highest in the Fall season.

The easiest way to locate the constellation is to simply look up, and try to spot the shape of a "W" or "M". It lies between Perseus and Cepheus, as well as the North Star Polaris and the brightest galaxy in the sky, the Andromeda Galaxy.

[As seen in The Constellations Handbook]

Cassiopeia was a proud, but arrogant mother. She put herself in danger when she shouted that both she and her daughter were more beautiful than the sea nymphs, the Nereids.
 

This infuriated the god of the sea, Poseidon, who sent the sea monster Cetus to ravage the land of Aethiopa. Not knowing what to do to stop this attack on their people, the king and the queen traveled to the Libyan desert to find an oracle and ask for advice. The answer they received was heart-breaking.

The only way to stop Cetus was to surrender Andromeda and let the sea monster eat her. Anguished, the king and queen were convinced by the people of Aethiopia to concede, and Cepheus chained his daughter to a rock near the water and left.

 As the sea monster approached the powerless princess, the hero Perseus and his flying horse Pegasus appeared over the scene. They were flying back after having decapitated the Gorgon, Medusa, when Perseus spotted the beautiful woman and immediately fell in love with her. The duo landed and, with a promise of marrying Andromeda, used Medusa’s head to turn Cetus into stone thus slaying the monster.

 Cepheus, Cassiopeia, and the citizens of the land of Aethiopia thanked Perseus for his courage. He later married princess Andromeda with her father’s full support.
 Poseidon, enraged at the outcome of his plan, decided to chain Cassiopeia to the sky, trapped for life. The queen spends half of each year upside down in the heavens as punishment for her words.

You can learn all about Cassiopeia and all 87 other constellations in The Constellations Handbook!

The 88 constellations are divided by groups, in the orders in which they interact with each other either in theme, mythology, or placement in the sky.

There are four main parts in the book, each part being linked to the astronomer who introduced them.

For each constellation, you will learn the stories associated with them, what deep sky objects can be seen in their vicinity, a map to find them in the night sky, if there are any meteor showers happening in them, our tips to remember them easily, and more!

Cassiopeia is home to several popular nebulae, such as:

You can also spot two Messier objects, both being open star clusters:

A few examples are shown below. Click on the images to read more about the target!

The Heart Nebula (IC 1805) is a large emission nebula.

It got this nickname because of its shape which looks like a heart (or something else if you have a dirty mind).

The bottom right of the image shows the Fish Head Nebula, which is technically part of the Heart but has a distinct name.

The Soul Nebula (IC 1848) is very close to the Heart Nebula, and the two are often photographed as a pair using a small refractor telescope or just a camera lens.

The Soul Nebula is divided into one large and one smaller blob of gas. It is located 7,500 light years away and is rich in both Hydrogen Alpha and Oxygen III.

The Ghost of Cassiopeia is a very faint nebula that is barely visible due to its proximity with the bright star Gamma Cassiopeiae.

Gamma Cassiopeiae can be seen in the center of our main image. It is the middle star in "W" shape. The Ghost of Cassiopeia refers to the nebula seen on the picture on the left, IC 63, but it also has a companion right next to it, IC 59.

IC 59 is very similar to IC 63 in terms of composition, magnitude, and size.

The Bubble Nebula (NGC 7635) is a large emission nebula about 10,000 light-years away. The Bubble itself is bright and colorful, but it also has an enormous amount of fainter gas all around.

Imaging the Bubble Nebula with a small wide-field telescope is great, because you can also capture two extra deep sky objects in your field of view!

One of them is Messier 52, a bright open cluster very close to the Bubble. The second one is Sh2-157, a massive nebula with the shape of a claw, hence its nickname "Lobster Claw Nebula".

M52 is visible to the upper left, Sh2-157 is visible on the lower right.

Be sure to click the picture to see the high-resolution version.

Messier 103 is a small but beautiful open cluster made up of at least 172 stars.

The cluster is not far from one of Cassiopeia's brightest stars, Ruchbah, so make sure you don't do the same mistake we did and frame the star just outside of your frame, or you likely will have bright light rays coming from one of your corners. Using a large telescope is best when imaging M103 due to the cluster's small size and the lack of any other object around it.

The Pacman Nebula is a colorful gas formation nebula about 9,500 light-years away.

This deep sky object is great for any size telescope and is a great bicolor target as it is rich in both Hydrogen Alpha and Oxygen III gases.

The nebula also looks great in broadband, as long as you capture it from a place away from light pollution. Just like any emission nebulae, using a modified DSLR or mirrorless camera will of course have a huge impact on the end result.

Cassiopeia is one of the most interesting constellations in the night sky. It has many popular and bright deep sky objects, and is high in the sky for a long period of time.

On top of that, Cassiopeia is very easy to spot in the sky, and can also be used to star hop to both Polaris (the North Star) and the Andromeda Galaxy (M31)!

Have you photographed the constellation Cassiopeia? If so, attach your image in the comments section, we'd love to see it!

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