A diagram of galaxies visible in Boötes. | SkyNews
Galaxies in Boötes (Chris Vaughan, Stellarium)

Great spring galactic adventures

Trek through Leo and Boötes this spring to find a treasure trove of galaxies hidden in plain sight.

While we wait for the Milky Way and its splendours to take centre stage in the southern sky this summer, late spring will provide plenty of galaxies to fill our warmer and increasingly clear nights.

Add to your deep-sky repertoire by viewing these galaxies that are hiding in plain sight, tucked close-in to naked-eye stars or sitting beside some already-familiar Messier objects.  

Blake Nancarrow sketched the Cocoon Galaxy on May 5, 2013. | SkyNews
Blake Nancarrow sketched the Cocoon Galaxy on May 5, 2013.

There are many more glorious objects to be seen, and different ways to see them. Check out Chris Vaughan’s article “Hiding in plain sight” in the May/June 2021 edition of SkyNews for more!

The Leo region

The southern night sky as seen from Toronto at 11 p.m. EDT on May 11, 2021. (Chris Vaughan, Stellarium)

During the April and May moonless periods, the constellation of Leo will still be positioned high enough in the western evening sky to view galaxies beside two of its bright stars. Leo I or UGC 5470 is a large (12 × 8 arc minutes across), oval elliptical galaxy centred only 20 arc minutes north of Regulus. While the galaxy’s reported visual magnitude is 10.3, its low surface brightness and proximity to such a bright star will make it a challenge to observe. But very dark, transparent skies should allow you to see it, even in smaller telescopes. Located only 820,000 light-years from us, Leo I is theorized to be the most distant of our Milky Way’s satellite galaxies. 

For an easier target, look for the slightly edge-on spiral galaxy NGC 3227 and its smaller, but slightly brighter partner, the elliptical galaxy NGC 3226. They are positioned 50 arc minutes east of Algieba (γ Leo) — the star that marks the throat of the lion — so you’ll need to put Algieba on the west edge of your field of view and look for the galaxies across from it. Viewed together, the two galaxies resemble a half-sized Messier 51, the Whirlpool Galaxy. Owing to their magnitudes of 10.3 and 11.8, NGC 3227 and 3226 are visible in medium-sized (3-inch or 4-inch aperture and greater) telescopes, through which they’ll show a pair of star-like cores two arc minutes apart arranged north-south and enveloped in faint, oval haloes. A large aperture telescope (10-inch and above) will allow you to observe the contrast in structure between the two galaxy types.

Boötes and beyond

A diagram of galaxies visible in Boötes. | SkyNews
Galaxies in Boötes (Chris Vaughan, Stellarium)

Near the northwestern corner of Boötes sits a narrow triangle of medium-bright stars that represent the herdsman’s upraised hand, namely Asellus Primus, Secundus and Tertius — “First, Second, and Third Donkey.” A few degrees to their southeast are two magnitude 5.5 stars separated by one degree and designated CH Boo and g Boo. Aim your telescope directly between CH Boo and g Boo and look for two small, but relatively high-surface brightness galaxies 30 arc minutes apart on the line joining the two stars. (You may need to slew east and west a bit to bring each star into view.) NGC 5676 is an oblique, northeast-southwest-oriented spiral about 1 × 3 arc minutes across surrounding a stellar core. A large aperture telescope should show brightening in the southwestern side. NGC 5660 is a face-on spiral, two arc minutes across with a bright core. A pair of smaller, edge-on spirals, IC 1029 and NGC 5673 are positioned half a degree northeast of that line. While these four galaxies are more challenging than my other suggestions, they will be aided by their position nearly overhead in late evening, and they won’t be sharing the eyepiece with nearby bright stars.

Chris Vaughan is a science writer, geophysicist, astronomer, planetary scientist and an “outreach RASCal.” He writes Astronomy Skylights, and you can follow him on Twitter at @astrogeoguy. He can also bring his Digital Starlab portable inflatable planetarium to your school or other daytime or evening event. Contact him through AstroGeo.ca to tour the universe together.

Chris Vaughan and Blake Nancarrow have been working on a Stellarium bookmarks page on the RASC Toronto Centre website. You can visit the page — and see the objects Chris mentions in his May-June 2021 SkyNews article — here.