Spring is often called Galaxy Season, because it is one of the best times of the year to observe our galactic neighbors.  Why?  What makes spring so special for galaxies?  Location, location, location!

Our Position in the Milky Way

The earth and planets of the solar system orbit the sun in a flat circle called “the ecliptic.”  This circle tilts at a 60 degree angle with the plane of the Milky Way.  As the earth orbits the sun, our night-sky faces “upwards” away from the galaxy in the spring, inwards toward the center of the galaxy in summer, “downwards” away the galaxy in the fall, and outwards toward the outer bands of the galaxy in the winter. (see diagram in the newsletter online)

During spring and fall, without the obscuring gas and dust in the galactic plane, we can see literally billions of light years into deep space.

The North Galactic Pole

This month, when you look straight overhead (from the northern hemisphere), you are looking towards the “North Galactic Pole” (NGP).  The NGP is a point in the sky that represents the north pole of the Milky Way Galaxy, analogous to the earth’s north celestial pole.  There is no galactic “north star;” but the NGP is located near the star 31-Com along the northern border of the constellation Coma Berenices (Com). 

Exploring the Galactic North

Coma Berenices is difficult to find in all but the darkest of skies.  It is a roughly square-shaped constellation centered between 4 better known constellations: Ursa Major to the north, Boötes to the east, Virgo to the south, and Leo to the west.  (See map on back of newsletter.)  Together these constellations map the galactic north and the locations of many important deep sky objects, including:

• Melotte 111 is an open cluster in Com, 288 LY away.  It appears as a wide but dim stringy haze with the unaided eye, and as a bright smattering of stars in binoculars.  It’s not very interesting in larger telescopes due to their limited fields of view.  
• M3 is a bright globular cluster just east of β-Com, easily visible in binoculars as a small glowing orb among a background of stars, 33000 LY away.
• M35 is a globular cluster near α-com, 58000 lY away, and easy to spot with a small telescope. With a larger scope or camera, you might spot its very dim globular cluster neighbor, NGC 5053.
• Coma Galaxy Cluster is a large group of galaxies along the northern border of Com between stars  31- and 41-Com.  The coma cluster is a group of thousands of galaxies over 300 million LY away, well outside our own Virgo Supercluster.  NGC 4889 is the largest galaxy in this group, but it’s still too dim to see in small telescopes.  About the best most of us with small scopes can do is find 31- and 41-com and then just “know” they are there.  These galaxies were the first to suggest the existence of Dark Matter.
• M64 (The Black Eye Galaxy) is a relatively bright spiral galaxy visually near M35.  It is visible in small telescopes and even binoculars and is relatively close at 17 million LYs.  
• M85 is one of the largest and brightest galaxies in the Coma-Virgo cluster of galaxies, 60 million LY away.  You can find it in a telescope near star 11-com at the SW corner of Coma Berenices.  Below M85 lies the giant Virgo Galaxy Cluster.  
• M87 is one prominent member of the Virgo Galaxy Cluster. It is a giant elliptical galaxy 55 million LY away, found about half-way between the stars Vindemiatrix (ε-Virginis) and Denebola (β-Leonis).   M87 made news last month when an image of its supermassive black hole core was released to the public - the first ever photograph of a black hole!