Challenge #3 – C41, Hyades, Open Cluster in Taurus
| Target | Type | R. A. | Dec. | Constellation | Magnitude | Size |
| C41 (Mel 25) | Open Cluster | 04h 26m 54s | +15° 52′ 00″ | Taurus | +0.5 | 330 arcmin |
Overview
The Hyades is the head of Taurus the bull, a collection of several hundred stars in a very distinctive ‘V’ shape of brighter stars. It appears to include the famous bright red star Aldebaran but this is an optical illusion since Aldebaran is almost 90 light-years closer to us than the Hyades.
Roughly spherical, this ball of stars is the closest open cluster to Earth at just 153 light-years away. Its core is about nine light-years wide and its tidal influence extends to over 32 light-years. However, astronomers see stars outside of this distance that are part of the cluster, suggesting that it’s in the process of decaying; these more distant stars are leaving the cluster.
Five stars in the cluster are visible to the naked eye and they’re all within a few light years of each other.
The Hyades cluster is believed to be 625 million years old.
Finder Charts
The first sky chart, from SkySafari 6, shows the view looking south at 10 pm in the middle of January, looking southeast.
We’re looking for Taurus, which is an easy constellation to find. To get a guide for it, find Orion and the blurry light of the Pleiades. The horned Taurus is between these two objects, which are circled orange in the first finder chart.
This first chart shows stars to magnitude 5.0, and the moon and planets are not shown.
Taurus is famed for its two horns, and where they originate is where we find Hyades. It’s an easy discovery to make, but use the star Betelgeuse in Orion, joined to Meissa (the head) to point the way to Aldebaran if you’re having trouble. Aldebaran is at the extreme edge of the Hyades.
Stars are shown to magnitude seven in this final finder chart which reveals much more of the detail in this expansive star cluster.
In the last section, you’ll discover what you should expect to see of this excellent cluster once it’s in your eyepiece.
Individual Telescope Views
The following views will help you find C41 in different telescope types by presenting the images as your telescope will show them. The first image is with a black sky and white stars, the second picture is the same image but presented in inverse monochrome. Stars are shown to magnitude 10.0 and the circle is a 1.5° field of view.
Each image can be clicked on for a full-screen version.
Upright View – This is what your eyes see unaided and through a reflex or red-dot finderscope
Upside-down view – This is what reflectors and magnifying finders show, and refractors / Cassegrains without a star diagonal
Mirrored View – Refractors and Cassegrain models with a star diagonal show this view
Observation
Remarkably, I don’t have much to tell you here. It’s an irony that the most obvious views need less help for us to enjoy them.
This rich star field is a pleasure to enjoy with the naked eye, binoculars and a wide-field, low magnification telescope view. Using more powerful magnification, it’s an opportunity to spy myriad double stars and aim to separate some challengingly close neighbors. Look at 80 and 81 Tauri, Delta-3 and Struves 545 and 559 to see how you fare.
Looking at the stars generally, note they are predominantly orange and yellow. Compare these to the dazzling blues of the Pleiades and this hints at the difference in their ages. The young 100 million year upstart Pleiades versus the venerable 600 million year wisdom of the Hyades.
PDFs for Printing
Each of the star maps above is reproduced as a pdf below. Each star map has a number in [square brackets] beneath it which corresponds to the file number below. If you want image [C41-1], for example, click the ‘download’ button next to it below and you’ll be able to open it as a printable pdf.