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The Pleiades Star Cluster

The Pleiades is a gorgeous, 150 million-year-old open star cluster in the constellation Taurus. In the northern hemisphere, the fall and winter seasons are the best time to photograph the Pleiades. From mid-northern latitudes, this popular astrophotography target rises high enough into the sky to start collecting images by late September.

Although the cluster consists of over 1000 stars,  the “Seven Sisters” dominate your visual and photographic attention. The Pleiades star cluster is one of the nearest star clusters to Earth and the most obvious naked-eye cluster in the night sky.  

Pleiades

The Pleiades Star Cluster captured using a DSLR and telescope

On top of being an open star cluster, the Pleiades star cluster also contains striking blue reflection nebulae. The dusty cosmic cloud surrounding the Pleiades, and associated blue reflection nebula can be enjoyed through long-exposure astrophotography. 

The image above was created by capturing 25 x 3.5-minute images with a DSLR camera and telescope. To capture an image that highlights the faint, glowing dust that surrounds the Seven Sisters star cluster, dark skies that are well away from city light pollution are required. This APOD image shows just how dusty the area surround M45 is.

An interesting fact about the Pleiades star cluster is that Subaru is the Japanese name for this star cluster and the inspiration for this automotive company’s logo. 

The Pleiades Star Cluster

The Pleiades is visible from most parts of the globe and appears as a “misty dipper of stars” in Taurus. To find the Pleiades, use the bright orange star Aldebaran as a guide. If you draw an invisible line from Orion’s Belt to Aldebaran, you’ll eventually reach the Pleiades. 

With the unaided eye, most people count 6 stars in the Pleiades star cluster, not 7. With a pair of binoculars or a telescope, you will see many more stars in the cluster. Below, is a wide-field view of the Pleiades using a 105mm camera lens. This image is a good representation of what it’s like to observe M45 from a dark sky site through a small telescope.

Pleiades wide-field image

The Pleiades at 105mm using a DSLR and 24-105 Camera Lens

The image above showcases the Pleiades in a 7-degree wide field of view. At this magnification, at least 7 stars are obvious in the cluster and are typically what you’ll see from a dark sky location. The Seven Sister stars of the Pleiades are Maia, Electra, Alcyone, Taygeta, Asterope, Celaeno, and Merope. 

November is often called the month of the Pleiades. At this time of year, the Pleiades shine from dusk until dawn. In the image below, you’ll see the proximity of the Pleiades to the constellation Orion

the night sky with the Pleiades star cluster visible

The Pleiades star cluster can be seen to the right of the constellation Orion.

For many people, this star cluster is one of the first deep sky objects ever observed with their naked eye. There are very few deep sky objects that are as bright (apparent magnitude +1.6) and noticeable as the Pleiades. 

Binoculars are a great tool for observing the Pleiades, as this star cluster covers a relatively large area of sky (apparent dimensions 110′ arcmin.). A wide field of view from a pair of binoculars or a low power telescope will ensure that the entire cluster can be seen at the same time.

Few star clusters can deliver the excitement and awe that Messier 45 does through the eyepiece of a telescope. For a truly remarkable way to enjoy this object, consider attaching a camera to your telescope.

Astrophotography

astrophotography

A photograph of the Pleiades star cluster looks great at any focal length, from a wide-angle nightscape to a high magnification deep sky image. Whether you are using a camera lens, or a telescope, to effectively capture the faint, dusty details of the associated reflection nebula, a star tracker must be used to allow for long exposure imaging. 

Because the night sky appears to be moving from our vantage point on Earth, a tracking mount is needed to “freeze” the object in place. A simple astrophotography setup will include a tracking camera mount, and a DSLR camera with a telephoto lens attached.

For a deeper look into this object, an equatorial telescope mount will help to collect high magnification images using focal lengths of 500mm or more. The astrophotography setup shown below is responsible for the photo of M45 at the top of this page.

astrophotography telescope

A refractor telescope attached to an EQ mount for astrophotography.

The telescope is an Explore Scientific ED80, and the mount is a Celestron CG-5 (Now the Celestron AVX). This telescope is on my list of best beginner astrophotography telescopes. Apochromatic refractors are an excellent choice for astrophotography, especially for those transitioning from a camera lens to a telescope.

For this target, the biggest advantage you can give yourself is to shoot under dark skies away from city light pollution. Reflection nebulae are broadband color targets, that do not benefit from narrowband filters to isolate specific gases. 

By stacking multiple exposures together in software called DeepSkyStacker, I was able to increase the signal-to-noise ratio of the image. This makes image processing much easier, as the camera noise is reduced, and the fine details from the nebula can be gently pulled forward.

Related: Download my Astrophotography Image Processing Guide

M45 star cluster

Photo Details

  • Camera: Canon EOS Rebel Xsi (stock)
  • Telescope: Explore Scientific ED80 Triplet APO refractor
  • Mount: Celestron Advanced Series CG-5
  • Total Exposure: 1 Hour, 27 Minutes
  • Sub Exposures: 25 x 3.5-minutes
  • White Balance: Auto
  • ISO: 1600
  • Calibration Frames: 16 Dark Frames, 16 Flat Frames, 16 Bias Frames
  • Stacking and Calibration: DeepSkyStacker
  • Final Processing: Adobe Photoshop CC

The Explore Scientific ED80 is a triplet apochromatic refractor telescope with an 80mm ED objective lens. With a focal length of 480mm and an f-ratio of F/6, this refractor is truly versatile for medium-to-large deep sky objects such as M45.

This telescope is compact, easy to transport, and includes features that are important for astrophotography like a 10-1 speed focuser with adjustable tension and lock. This was my first “true” astrophotography telescope, and it helped me get over the steep learning curve involved with deep sky astrophotography early on. 

explore scientific ed80

Camera Settings and Tips

For this target, any camera capable of astrophotography will do. A stock DSLR camera (such as the Canon EOS Rebel Xsi) is capable of producing incredible images of this cluster. Reflection nebulae, in general, do not require a modified DSLR camera to record effectively.

The additional wavelengths of light captured with a full-spectrum modified camera are most beneficial for capturing Ha (Hydrogen-alpha), not the glowing blue light of the reflection nebulosity found in the Pleiades.

You’ll want to use manual mode on your camera, and set the camera dial to bulb mode to collect ultra-long exposures of at least 2-minutes each or more. Longer exposures will begin to reveal the faint outer nebulosity and dust surrounding the star cluster.

By shooting your image in RAW format, the white balance setting you choose is irrelevant, as you can change this later in post-processing. However, I usually leave the white balance set to auto or daylight for all of my astrophotography images as a starting point.

DSLR camera

To focus the star cluster using a DSLR in both a camera lens and/or telescope, I recommend using the live-view feature on your camera. You can then zoom-in to 10X to make fine adjustments to the focus until the bright stars are as sharp as possible.

Here are some more astrophotography tips that apply to a wide variety of imaging scenarios:

  • Use a “fast” aperture of F/2.8 – F/4
  • Set your white balance setting to daylight
  • Use manual mode
  • Set exposure length at 30 seconds
  • Shoot in RAW image format
  • Use an ISO of 400-1600 (or more)

A light pollution filter can help to isolate deep sky objects from a washed-out city sky, but there is no substitute for dark skies. For M45 in particular, you will benefit from taking your image from a dark sky site during the new moon phase.

As an example, have a look at the unprocessed single frame vs. a color balanced version. This photo was captured using a DSLR and camera lens from my Bortle Class 8 backyard in the heart of the city. The lens used was a Canon EF 24-105mm F4/L at it’s the maximum focal length of 105mm.

White Balance Settings for Astrophotography

An unprocessed single frame of the Pleiades from the city vs. stacked and corrected version

There is a massive amount of dust within the Pleiades star cluster and can be captured in detail with enough exposure time. This 12-hour exposure displays just how much dust there really is surrounding the Pleiades star cluster.

One of the benefits of shooting Pleiades with a DSLR camera is the ability to focus using the bright stars of M45. Unlike many faint nebulae and globular clusters in the night sky, Pleiades is easy to find and shows up well in your camera’s live view screen.

The majority of the deep sky objects I photograph are far too dim to identify through a camera lens with my DSLR. Thankfully, Pleiades is an exception to this, which is why it is such a popular deep sky target for beginners.

M45 - Pleiades

My first image of the Pleiades from 2011

Using a Full Frame DSLR Camera

A full-frame DSLR camera and a wide field telescope is a great combination to use when photographing this star cluster. The image below was captured using a stock Canon 5D Mk II and a William Optics Zenithstar 73.

An Optolong L-Pro broadband filter helped to reduce city glow without creating any harsh color casts. It’s worth mentioning that this shot was captured from a red zone, with a 60% illuminated moon nearby:

Pleiades L-Pro

Image Processing

The challenge when processing Messier 45 is the extremely bright and large stars in the image. These stars may have caused some odd reflections in your image, that will be to be removed using either the clone tool or healing brush. The content-aware fill feature in Adobe Photoshop will also handle the task quite well.

The image processing steps needed for an image of a star cluster are quite different than they are for a galaxy or nebula. Because the focus is on the stars themselves, less stretching (curves, levels) of the data is needed.

image processing

Learn the process of removing reflections in your astrophotos in my complete image processing guide.

For most of my deep-sky images, my goal is to tame the bright stars and pull the light from the DSO (deep-sky object) forward. The Pleiades is a challenge because the stars and reflection nebulae are featured together. This is why you will see so many variations of M45 with fluctuating amounts of nebulosity.

M45 is a tremendous deep sky astrophotography target, no matter what photography equipment you’re using. I hope that my experiences photographing the Pleiades over the years have inspired you to take your own shot.

Photographing Pleiades