NGC 2683

NGC 2683 spiral galaxy. Image source: [1]

  It was February 5, 1788 when the great German astronomer William Herschel discovered the marvelous galaxy NGC 2683, which we can now admire in great detail thanks to the images of it captured by the Hubble Space Telescope.  

  NGC 2683 is a bright spiral galaxy, recently considered barred, with a bright nucleus and an inclination of about 20 degrees that shows us the typical form of other galaxies like NGC 7331 or M31, perhaps a little less inclined towards them. In addition to its nucleus the yellowish and reddish colors of mature stars predominate and a reduced rate of star formation. Numerous bands of dark gas break their light into thousands of fragments. Unlike others, NGC 2683 is a relatively static galaxy that moves away from us at more than 400 kilometers per second. It is also rich in globular clusters twice as large as the Milky Way. 

NGC 2683 observed by the Hubble Space Telescope. Image source: [2]

Messier 3

 

Mount Lemmon SkyCenter image of Messier 3. Image source: [3]

  Globular clusters are peculiar in their history and composition, Messier 3 is not far behind. Discovered in 1764 by Charles Messier and cataloged with the number 3, it was actually the object that made him commit to developing a list of celestial nebulae to avoid getting confused in his quest for comets. He saw only a round nebula with nothing in it, William Herschel being the first to solve its stars. Messier 3 is an ancient cluster, its origin is 11 billion years (remember that the universe was born about 13.7 billion years ago and our sun 4.5 billion years ago).  

  Messier is about 33,900 light years away, it is farther from us than the center of our own galaxy, but it shines with an intensity 300,000 times higher than the sun (if we put the Sun in its place, our star would be invisible except for professional telescopes). It has a diameter of about 180 light years, perhaps 200, but its Roche limit (ie in the case of clusters, we refer to the point from which the stars would be expelled to the Milky Way), is much larger, covering a sphere with a diameter of about 760 light-years. Or put another way, all the stars within that sphere are gravitationally tied to Messier 3. This cluster is one of the largest and brightest: according to recent calculations it is made up of about 500,000 stars.  

Messier 3 with amateur telescope. Image source: [4]