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The Stunning Double Cluster in Perseus

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The Double Cluster in Perseus

The Double Cluster in Perseus (NGC 869 and NGC 884) are two open clusters in the constellation Perseus. Also named Caldwell 14 or simply “The Double Cluster”, both star clusters are very similar to each other in size, magnitude, and age.

This pair of open clusters lie about 7,000 light-years away from Earth. They are an easy binocular target, and an impressive sight through a small telescope.

The Double Cluster

The magnitude 3.7-3.8 star clusters are bright enough to be spotted with the naked eye under the right conditions. Each of the clusters contains more than 300 blue/white super-giant stars. The photo shown above was captured from a dark sky site (Bortle Scale class 4) using a Canon EOS 60Da camera, and a Rokinon 135mm F/2 lens

The image was created by capturing several 90-second image exposures and stacking the images together. A star tracker was used to compensate for the apparent rotation of the night sky, to capture sharp stars across the field.

The long-exposure image below displays the beautiful mix of warm and cool stars in the area, with the prominent blue/white stars of the double cluster. This image was captured through a refractor telescope (Astro Tech 72ED) and a Canon EOS T3i DSLR by Brent Newton

The Double Cluster

The Double Cluster in Perseus. Brent Newton.

NGC 869 and NGC 884 (The Double Cluster)

  • Common Name: The Double Cluster
  • Cataloged: NGC 869, NGC 884, Caldwell 14
  • Constellation: Perseus
  • Distance: 7,500 ly (2,300 Pc)
  • Apparent dimensions (V): 60′
  • Apparent magnitude (V): 3.7 and 3.8
  • Age: 12.8 Million Years

The Double Cluster occupies a total area of about 60 arc minutes. For comparison, the full Moon is approximately 30 arc minutes in size. Each cluster is surrounded by an extended halo of stars, and are only separated by a few hundred light-years.

The open star clusters were first cataloged around 130 BC when the Greek astronomer Hipparchos mentioned it as a “nebula” or “cloudy spot” in his writings. It was not until the invention of the telescope in the early 17th century, that the true nature of the Double Cluster in Perseus was realized. 

The Messier Catalog does not include the Double Cluster, but it is listed in the Caldwell, and NGC catalogs. Astronomer William Herschel was the first one to recognize that this “cloudy spot” in the night sky consisted of two separate clusters of stars.

Caldwell 14

Views of NGC 869 and NGC 884 at varying magnifications.

Each cluster contains roughly 300-400 stars that are approximately 300 million years old. From a dark sky location during the new moon phase, you may be able to see the hazy pathway of the winter Milky Way crossing this part of the sky.

Location

The Double Cluster lies directly between the constellations Perseus, and Cassiopeia. At magnitude 3.7 and 3.8, NGC 869 and NGC 884 are brighter than many of the other open clusters in the night sky, and this makes them easier to find. 

The easiest way to find the Double Cluster in Perseus is to travel downwards from the constellation Cassiopeia. Under moderately dark skies, you should see a faint glow of stars below the 2 bright stars at the bottom of the “W” shape of Cassiopeia (Ruchbah and Epsilon Cassiopeiae).

Related Video: Two Ways to find the Double Cluster in Perseus

Some find it helpful to draw an imaginary line from the stars Navi, and Ruchbah in Cassiopeia. Following this path, you will eventually run into the Double Cluster in a pair of binoculars. 

Through a pair of binoculars, the two clusters of stars turn from a faint smudge, into two distinct groupings of stars. From mid-northern latitudes, the best time to look for the Double Cluster in Perseus is in the fall. 

double cluster location

The location of the Double Cluster between Cassiopeia and Perseus.

I remember the first time I saw the Double Cluster through the eyepiece of my telescope, and it was one of the most exciting observations I had made at the time. The number of intensely bright stars in a single field of view is remarkable, and it is one of the most satisfying views in the entire night sky. 

Try scanning past the area of Perseus where the clusters are located using a wide-field eyepiece. When the Double Cluster appears in view, you’ll want to enjoy the sight for an extended period of time. A wide-field telescope eyepiece (25mm or more) is recommended.

The Double Cluster lies close by to the popular Heart and Soul Nebulae region, as shown in the image below by Robin Onderka. Be sure to view the full-size image on Flickr as well.

Double Cluster and Heart and Soul Nebulae

The Double Cluster, the Heart Nebula, and the Soul Nebula. Robin Onderka.

location in the night sky

The Constellation Perseus.

What is an Open Cluster?

An open cluster is a group of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. Open clusters are loosely bound together by gravitational attraction, yet become disrupted by close encounters with other clusters and gas clouds as they orbit the galactic center

The Pleiades is perhaps the most popular open cluster in the night sky, easily observed with the naked eye in the constellation Taurus. Over 1000 open clusters have been discovered within the Milky Way Galaxy, and many more are presumed to exist. Open clusters can survive for over a hundred million years. Globular clusters exert a stronger gravitational attraction on their members and can survive even longer. 

Open clusters are found in the disk of the Galaxy and therefore lie largely in the plane of the Milky Way. Many of the closest open clusters are easily visible to the naked eye. To help you find the location of the brightest Open Clusters in the night sky, it is helpful to use a stargazing app on your smartphone. 

Double Cluster with H-Alpha

The Double Cluster with surrounding H-alpha nebulosity. (View Full-Size version on Flickr)

The image above was captured by Nico Carver (Nebula Photos) to highlight the hydrogen gas present in the area. Nico combined a DSLR shot of the double cluster with a deep shot of the surrounding h-alpha emission from a mono camera.

Well-Known Open Clusters

Helpful Resources:

the night sky

This article was originally published on February 16, 2016, and updated on October 22, 2020.

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Astrophotography in the City

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Saturday Night Under the Stars

Astrophotography in the City

Last weekend I posted a new video to my YouTube channel titled DSLR Astrophotography – A Night in the Backyard with my Camera. It is now Early-April, and we are in what amateur astrophotographers call “Galaxy Season”, as we transition from the Winter Constellations like Orion and Taurus, to the Summer Milky Way objects.  In between, there are some fantastic deep-sky objects to observe in the Spring Constellations Leo, Coma Berenices, and Bootes.

The forecast called for clear skies on that crisp, cold Saturday night in Southern Ontario, and I was ready to image some deep-sky objects with my camera and telescope.  After a late dinner, it was a race against the clock to photograph my first subject of the evening, the Waxing Crescent Moon. If you want to jump straight to the video, you can find it at the bottom of this post.

Live-View DSLR Through a Telescope

Using the Canon 70D’s live view screen for telescope observing

Crescent Moon Astrophotography

 

I barely had time to get the beautiful Waxing Crescent moon into my telescope’s eyepiece before it became obscured by the surrounding trees in my neighborhood!  I shot a live-view video of the moon (with Earthshine visible) with my Canon EOS 70D DSLR through the telescope.  This may be of interest to anyone wondering what the view is like through an 80mm refractor telescope.  You need an adapter to attach the camera to the telescope, which you can buy online here.

After I focused the Moon and experimented with different ISO settings and exposure lengths, I snapped a couple of shots before moving on with the rest of my night.  You can have a look at the equipment I use for astrophotography here.

 

Earthshine Moon

The sky from my backyard

Next, I wanted to provide some examples of the dark-sky quality from my backyard.  Living in the central part of town has its advantages, but dark skies are not one of them!  I experience heavy light pollution from all directions.  This makes using a light-pollution filter on my camera necessary for long exposures.  Currently, I use the IDAS LPS clip-in filter on my Canon Rebel Xsi DSLR.  This allows me to capture exposures of up to 5 minutes from my backyard.

 

Astrophotography in the City

The night sky from my backyard on April 9, 2016

 

The Big Dipper Asterism

Looking towards the Big Dipper in Ursa Major

Deep-Sky Target: Edge-On Spiral Galaxy in Coma Berenices

NGC 4565 – The Needle Galaxy

Once the moon had set, I promptly prepared my deep-sky astrophotography rig for a night’s worth of photons on my photography subject.  I settled on NGC 4565 – The Needle Galaxy because of it’s size, magnitude, and current location in our night sky.  The Needle Galaxy is an edge-on spiral galaxy that resides about 30-50 million lights years from Earth.  This handsome galaxy is the current photo in my 2016 RASC Observer’s Calendar hanging in my office at work, perhaps that is what gave me the idea!

Astrophotography in the City - Needle Galaxy from my backyard

NGC 4565 – The Needle Galaxy

Photographed on: April 9/10, 2016

Total Exposure Time: 54 Minutes (18 x 3 Min. Subs @ ISO 1600)
Mount: Sky-Watcher HEQ-5 Pro
Camera: Canon 450D (modified)
Telescope: Explore Scientific ED80 Triplet Apo

Guided with PHD Guiding
Stacked in Deep Sky Stacker
Processed in Adobe Photoshop CC

This interesting NGC object shows up rather small in my 80mm telescope, as many galaxies do.  A larger telescope with a focal length of 1000mm or more would be a better choice for this DSO.  I also had a bit of a challenging evening out the background colour of this image.  Flat frames would have made this issue much easier to deal with in post-processing.  With just under an hour of exposure time, it is safe to say that I will need to add more time to this image to bring out the colour and detail.


AstroBackyard on Youtube

I am completely blown away with the response to my YouTube Channel has received.  Thank you to everyone who has subscribed, I look forward to many new astrophotography videos in the future!

Beginner Advice:

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M42 – The Gorgeous Orion Nebula

|Nebulae|3 Comments

Located below Orion’s Belt, the Orion Nebula is now gracing our skies each night

The skies were clear in Niagara last weekend, so I set up my telescope for a night of astrophotography imaging. There are so many great imaging options at this time of year. The Pleiades, the Pacman Nebula, the Andromeda Galaxy, the Triangulum Galaxy and the Dumbbell Nebula are all on display right now, to name a few.

I settled on the Orion Nebula because it’s an “all-nighter” object from my backyard viewing area. I set my trusty Canon 450D to capture 60 three minute exposures while I slept. The focusing, framing and camera control was all accomplished with my new favorite piece of astronomy software, Backyard EOS.

I find that I am able to achieve an extra tight focus on this deep-sky object because of the 4 stars (Trapezium) located within the Orion Nebula. They seem to be the perfect size for my cameras live-view preview screen at 10 X view. I may use this “focus-test” for imaging nearby objects in Orion such as the Rosette Nebula and M78. I’ll calibrate the mount, hop over to M42 for a tight focus, and then frame the new object up afterward.

I decided to include the Running Man Nebula (NGC 1973, NGC 1975 and NGC 1977) because I feel that it completes the image and fits so nicely in my field of view. A larger telescope would be more suited for an isolated shot of Messier 42 on its own.

Orion Nebula - Astrophotography Image

M42, NGC 1973, NGC 1975, NGC 1977

PHOTO DETAILS

50 x 3 min frames @ ISO 800
Total Exposure Time = 2 Hours, 30 Minutes
20 Dark Frames Subtracted
Canon Xsi Camera through 80mm APO Refractor

Learn how I process my images in Adobe Photoshop (Tutorial)

How to find M42 – The Orion Nebula

If you want to locate this glorious nebula, you will first have to locate the Orion constellation in the night sky. It is very easy to spot, if you’re looking at the right time of year. The winter months in The Northern Hemisphere are the perfect time to get familiarized with this exquisite creation of the Heavens. The constellation is unmistakable once after you spot the three medium-bright stars in a short, straight row that make up Orion’s Belt.

The Orion Nebula is perhaps the best deep-sky target for a beginner. Here are some general tips for getting started in astrophotography:

Beginner Astrophotography – How to Get Started and What You Need

Under dark skies, you should be able to find the Orion Nebula quite easily below Orion’s Belt. A careful observation with the naked eye will reveal a curved line of stars “hanging” from the three stars of Orion’s Belt. This collection of stars represents Orion’s Sword. Look for Orion Nebula (also known as M42) about midway down the Sword of Orion. Your eyes will see it as a small, hazy white spot. A long-exposure photograph like the one above brings out substantially more detail than can be observed with the naked eye.

The constellation of Orion

Observing the Orion Constellation this Winter

M42 is a wondrous sight through a pair of binoculars. Start by locating the three stars in Orion’s Belt, and move downward towards Orion’s sword. You will know when you have found the Orion Nebula because it is one of the most rewarding celestial treasures one can observe.

This enormous cloud of gas and dust lies approximately 1,300 light-years from Earth. This giant nebulous cocoon is giving birth to an estimated 1000 stars. The four brightest stars located within the open star cluster included in the nebula, are known as the Trapezium and can be distinguished when looking through a backyard telescope.

field of view

The Orion Nebula imaged through a Meade 70mm APO telescope.  

I plan on observing and imaging this brilliant winter constellation over the next few months. I hope I have inspired you to get out with your binoculars or telescope and enjoy the beauty of the night sky with your family!

Orion Nebula Video Close Up

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