# Meet the Deep Sky Objects - Messier 3

# Introduction

First post of our series Meet the Deep Sky Objects (MtDSO) on Messier 3 Globular Cluster. We will cover some basics of DSO observation and get details on one specific object in our articles.

One important point: the list is certainly really long but ours is going to be shorter. The good reason? We will only talk about the objects we have actually observed and sketched!

# Messier, Deep Sky Objects?! What's all that?

If you are new to astronomy or considering the hobby (come to the dark side, we have Eskimo!), it might sound a bit overwhelming. There is a lot of terms and lingo that you might not understand. Don't worry, it's only so astronomers look smart at dinners!

First of all, what is an "object"? Well, it's basically anything that you can "see" in the night sky. It can be a star (or more often double or triple stars), a type of interstellar gas cloud, groups of stars (that we name clusters), planets or exoplanet, etc. Of course, not all of these objects can be seen with the naked eye.

That being said, you can already see some of them with the naked eye or with basic binoculars. Do not expect Hubble-like views however...

Now that we know what an object is in astronomy, we can define a deep sky object or DSO. It is simply any object outside of our own solar system.
You will often come across these 2 acronyms: DSO (Deep Sky Object) and SSO (Solar System Object).

Messier is the name of a list. A list of celestial objects of course. The name comes from Charles Messier, who was an extremely classy, borderline swag, French astronomer of the XVIII century.

Charles Messier

Charles was a comet hunter, and he did not really appreciate mistaking something for a comet... Not at all. So to his and other astronomers benefits he published a list of objects not to be mistaken for comets.
Keep in mind that at that time, finding and naming a comet was the royal way to be famous and recognized. Likewise, mistaking these faint fuzzy objects for a comet was a sure way of being ridiculed. So Charles the Swag decided that enough was enough and created a catalog so he and everyone else, would stop wasting their time on these non-comet, uninteresting objects.
Ironically, this is now the most common catalog to go through when one seriously starts astronomy.

TL;DR: Messier is the name of a past scientist and of a deep sky objects catalog.

For a more complete list of definitions, please see our very own Glow-ssary (ahah...).

# Messier 3

# Discovery

Messier 3 or M3, is a globular cluster in the constellation Canes Venatici, or as the name so visually suggest: a big ball of stars. Lots of stars. Approximately 500 000 stars in this particular case.
You read correctly: this ball is made of 500 000 stars (like our own Sun)! To be perfectly exact, they are not all like our Sun as the whole globular cluster weights only 450 000 times our Sun.

Let that sink in your mind and get ready for more astonishing facts and number!

M3 is the first DSO directly discovered by Charles Messier. Fun fact, the rock star astronomer mistook it for a nebula at first. It was later corrected by another rock star astronomer: William Herschel.

To understand how Messier could mistake M3:

M3 by the Hubble Space Telescope

For a nebula (which is an interstellar gas cloud) like this one (M57, The Ring Nebula):

Ring Nebula by the Hubble Space Telescope

Credits: both images are from the Hubble Space Telescope and are hosted on Wikipedia.

You have to take in consideration that Charles only had 100mm of telescope aperture (4 inches)! This is literally nothing compared to modern astronomy!
As a comparison, here is a sketch of M3 through a 12 inches telescope (3 times bigger than Messier's):

M3 through a 12 inches telescope

Credits: Astronomy Sketch of the Day: Messier 3

Telescope aperture is critical in observation as the larger the aperture, the more photons (light) you gather. More light is equal to more details (or higher resolution).

Anyway, Charles Messier is credited for the discovery of this globular cluster on May the 3rd, 1764.

# Find it

# In the sky

Naked eye observation is close to impossible even in a very dark site (far from any light pollution), as it is a fairly dim object. Astronomers use the term apparent magnitude to refers to the measure of the brightness of an object seen from Earth. The magnitude scale is logarithmic and the bigger the number, the dimmer the object. A negative number means the object is very bright. To the point it can be seen in broad daylight.
For example:

  • The Sun: -26.7
  • The Moon: -12.6
  • Venus: -4.4
  • Vega: 0

M3 has an apparent magnitude of 6.3 and a surface brightness of 11. Any telescope from 4 inches of aperture will let you see M3. The difference is going to be in how many stars you can resolve in the cluster.

Finding it, is relatively easy as it is almost exactly between 2 bright stars: Arcturus and Cor Caroli. If you have a magnifying finder scope or binoculars it is going to look like a faint fuzzy smudge. Like a pale round milk stain.

Here is a finder charts:

M3 Charts

Credits: https://freestarcharts.com/messier-3

# In space

In space, M3 is part of our own Milky Way galaxy and is 33 900 light years away from Earth or 3.20719e+17 km (1.99285e+17 miles). Not an immediate destination for vacations!
It is also above the Galactic ecliptic by 31 600 light years (it is 31 600 light years above the ecliptic of the Milky Way) and 38 800 light years from the center of our galaxy.

# Interest / Rating


An excellent object to target for all kind of astronomers (represent a real challenge to sketch for seasoned astronomers) and non astronomers. Very interesting for star parties or observing session with kids. We highly recommend M3!

Kids/Non-astronomers (4 / 5):

An excellent object to show to kids & non astronomers.

Wow! factor (4.5 / 5):

The Wow! factor is here, it's a big bright object that non astronomers don't see everyday. Most of them are not even aware of it's existence.

Accessibility (4 / 5):

M3 is bright and well positioned, making it an easily findable and desirable target for beginners and star party.

This is clearly a very interesting object to look at. First because if nothing else, it's beautiful and most people will find it this way.
Second because it is relatively easy to find (when you are familiar with the night sky), and makes it an ideal target to show to kids. It is relatively bright for a DSO and therefor has a certain WOW effect.

Globular clusters are an all time favorite of star parties as it is not one of these deceptive objects (like galaxies). People have a very good idea of what is a galaxy thanks to space telescopes, but they don't really know globular clusters.

For that reason we recommend it as an early target for:

  • astronomers that are getting to the hobby,
  • star parties,
  • kids.

But let's be honest here: seasoned astronomers also love the globular clusters!

Here is a sketch from the Hyrule Astronomy Club: M3 M3 through a 16 inches Newtonian Reflector. Credits: Arnaud Dupuis

Clear skies!

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Last Updated: 5/27/2019, 5:32:31 AM