The Hyades Mosaic - The Closest Open Cluster to Earth | Astrophotography
The Hyades is a very large and bright open cluster in the constellation Taurus. It is the nearest open cluster to us at a distance of just 153 light-years. The Hyades are very close to another popular open cluster, the Pleiades. In this post, you will find information, images, and tips to photograph this beautiful star cluster.
Object Designation: Caldwell 41, Collinder 50, Melotte 25
Also known as: The Hyades
Constellation: Taurus
Object Type: Open Cluster
Distance: 153 light-years away
Magnitude: 0.5
Discovery: Known since prehistoric times. First catalogued by Giovanni Battista Hodierna in 1654
The Hyades are an easy target for beginner astrophotographers, although you will learn in this post that with a bit of patience and processing skills, you will be able to reveal so much more than just stars.
The Hyades rise high in the northern sky starting in October and stay high until February. This means the best time to photograph the Hyades is in the Winter season.
The Hyades Astrophotography Mosaic
November 2023
After making a 2x2 mosaic of Rho Ophiuchi, which looks incredible, it was time to attempt something larger and try a 3x2 mosaic!
I was looking for a good target that would fit just right in a 6-panel mosaic, and decided to go for the Hyades! Yes, this will certainly not be as impressive and colorful as our Rho Ophiuchi cloud complex, but we know that so much faint dust is hidden behind the bright stars of the Hyades.
I decided that spending about 8 hours on each panel would be a good idea. The sequence in NINA looked a bit messy with the 6 different tabs, and each pane took between one and three clear nights to complete.
As you can see below, a 6-panel mosaic is just the perfect size to include all of the Hyades cluster.
Click the image for the full-resolution version!
Download our practice data for one of the 6 panels!
GEAR USED:
Camera: ZWO ASI2600MC
Telescope: Celestron RASA 8
Mount: 10Micron GM1000 HPS
Guiding: ZWO ASI 220MM Mini
Accessories: Celestron Focuser / PrimaLuceLab Eagle 5S
Processing: Pixinsight, with R-C Astro plugins. Final touches in Skylum Luminar Neo
ACQUISITION DETAILS:
Total Exposure Time: 48 hours
Exposure Time per frame: 300 seconds
Filters: N/A
Gain: 100
How to Find the Hyades Cluster
The Hyades lie in the constellation Taurus, and are very easy to find as they rise not far after the bright Pleiades. They're also very easy to spot thanks to the large orange star Aldebaran. Aldebaran looks like it is part of the Hyades, but it is not gravitationally bound to the cluster and is just overlapping the object from our point of view.
The Hyades is our nearest open cluster, with a distance from Earth of just 153 light-years. Because of how bright and large the Hyades cluster is, it is very easy to spot with the naked eye, binoculars, and of course any telescope. Its large size makes it not possible to see it in its entirety through telescopes and large binoculars though, so the best way to observe the Hyades is by using a small pair of binoculars.
The Hyades are located between two famous regions of the sky with, on one side, Messier 45 (The Pleiades) and on the other, the Orion region with the Orion Nebula, the Horsehead Nebula, M78 and more. It is also not far from the first Messier object, the Crab Nebula.
The best time to observe and photograph the Hyades is in Winter.
Hyades Cluster Information
The Hyades is 625 million years old and contains 501 stars, with many more in close vicinity! The brightest member is Theta² Tauri, which forms a wide double star with Theta¹ Tauri. The pair can be seen easily in the picture by NASA attached in the next section. You can see the double star right in the center, with Theta¹ Tauri appearing orange and Theta² Tauri blue.
The Hyades by NASA
The image below was released by NASA and ESA on May 9th, 2013. This was not captured by a space telescope but instead by an Earth-based instrument, the DSS (Digital Sky Survey). It would have been simply impossible for the Hubble Space Telescope to get a good view of the Hyades due to its gigantic size. Two filters were used, red and blue.
The image shows the very bright star Aldebaran, and the stars making up the Hyades open cluster. As you can see, most of the stars in the cluster have a beautiful blue hue, with a few yellow and orange members.
Blue stars are very hot, while yellow stars are much cooler. You can see how packed and bright the center of the object is.
Aldebaran, the bright and large orange star, is much closer to Earth and is not linked to the cluster in any way. It is just 65 light-years away from us and is 150 brighter than our sun!
The Hyades in Greek Mythology
In Greek mythology, the Hyades are all sisters and female nature deities (also known as nymphs). They are known as the "rain-makers" as the sisterhood would bring rain. Their father is Atlas, and their mother is either Pleione or Aethra.
The Hyades had a brother, Hyas (meaning "rain"). When Hyas died in a hunting accident, the Hyades cried so much during their grief that they were sent to the head of Taurus and transformed into a cluster of stars.
The Greeks linked the rising and setting seasons of the Hyades to the rain season. The Hyades are also sisters to every astrophotographer's favorite "nymph", the Pleiades!
NGC 1555 and Sh2-239
The most interesting part of the mosaic of the Hyades we made is not the open cluster itself in my opinion, but instead the upper left section showing two very interesting nebulae: NGC 1555 and Sh2-239.
NGC 1555 is a variable nebula with a diameter of 4 light-years. It is also known as Hind's Variable Nebula, and can be seen on the right in our image below.
Sh2-239 is a star-forming region with a diameter of 3 light-years. It contains two known star clusters and several Herbig-Haro objects. It can be seen on the left in our image below.
Practice raw data is available for download if you'd like to process this file.
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Is There IFN Behind the Hyades?
The Hyades will, with long enough exposures, reveal some very faint dust in the background. This is exactly why I decided to capture this object and spend that many hours on it! Although the dust looks like IFN, and a lot of people believe it is and will say it is when sharing their pictures of this region online, it actually is not.
We have a full guide explaining what IFN is and how to capture it, so be sure to read it!
IFN is very faint interstellar dust that is being illuminated by all the stars in the Milky Way. It is present at high galactic latitudes and can be seen in the background of several deep-sky objects, such as the Iris Nebula, the M15 cluster, and many more.
IFN stands for Integrated Flux Nebula but, unlike "regular" nebulae, is not home to any star-forming activity. The dust behind the Hyades is very thick and comes from within our Milky Way. This type of dust, illuminated by the stars around it, is known as ISM (or Interstellar Medium). This specific dust around the Hyades is known as the Taurus Molecular Cloud (TMC-1).
IFN is very difficult to capture and process. It requires fast optics, patience, and a clean dark sky to pop up on your data. It is located far from the Milky Way plane, whereas ISM lies within the Milky Way arms and is slightly easier to shoot.
How to Process the Hyades with Molecular Clouds
Processing this 3x2 mosaic was of course messy, and slowed down my computer quite a bit. I ended up with hundreds of files, and kept the best 96 per panel which equaled to 576 frames in total.
I went through the typical mosaic creation workflow on PixInsight, which worked well and gave me one single file to work with which was gigantic at 118 Megapixels. Processing overall was very fun. I did my best to bring out the dust and am very happy with how much I was able to reveal without going too crazy.
If you'd like to learn exactly how I process images like this that contain so much dust and/or IFN, you can download our premium raw data pack which includes a full-resolution image of one of the panels used in this mosaic, along with a full walkthrough video showing you exactly how to process it and reveal as much dust as possible.
Utah Desert Remote Observatories
Having a telescope installed at Utah Desert Remote Observatories has been a blessing so far. We’ve been focusing on not capturing as many targets as possible, but rather on spending a ton of time on a few select targets. We love every single picture we took from UDRO so far, and really enjoyed the challenge of imaging very faint stuff that’s usually hidden behind a few of the less-exciting objects out there.
If you want to learn more about remote observatories and UDRO in general, be sure to watch the video below!
If you would like to permanently host your telescope next to ours under amazing desert skies, you can contact the owner at info@utahdesertremote.com
Hyades FAQ
In which constellation are the Hyades located?
You can find the Hyades in the constellation Taurus.
How big are the Hyades?
The cluster has a diameter of 20 light-years. From Earth, it has an apparent size of 330 arc minutes
How far are the Hyades?
The Hyades are located 153 light-years away from Earth.
How long should my exposure times be when photographing the Hyades?
This is an open cluster with a lot of dust in the background. We suggest doing long exposures between 5 and 30 minutes depending on your telescope and guiding accuracy. With our RASA 8 under Bortle 2 skies, we did 5-minute exposures which was enough.
Should I use a filter to image the Hyades?
No, you do not and should not use filters for the Hyades. This is a broadband target without any narrowband gas. The stars in the cluster and the dust in the background are better with no filters.
What equipment do I need to photograph the Hyades?
The Hyades are so large that they will not completely fit in your field of view even with a small telescope. This means that the best way to photograph them is to either use a DSLR/Mirrorless camera and lens to shoot the cluster wide-field, or to use a telescope and do a mosaic like we did. Either way, you'll want to use something fast so that the dust shows up well.
The telescope we used is the RASA 8 which has a focal length of 400mm and is very fast at f/2. The best lens to use for the Hyades would be the Rokinon 135mm which is also f/2 and has the perfect focal length for this target.
Final Thoughts
The Hyades is a huge and bright open cluster that happens to be very simple to photograph for amateur astrophotographers. If you have more experience, you'll also be able to capture and reveal the faint dust in the background of the object.
For the best results, either do a mosaic, or use a fast DSLR camera lens to be able to fit the entire object in your field of view!
Have you imaged the Hyades cluster? If so, upload your picture in the comments! We'd all love to see your work :)
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