This 360 degree panorama takes in the entire spring sky, with south at the bottom, and west to the right. The Milky Way appears low across the Northern Horizon at the top, coinciding with the arc of an aurora this night in April 2022. (Alan Dyer)
To backyard astronomers, spring is known as galaxy season, populated by prey best spotted in big telescopes. Are there targets suitable for humble binoculars? Absolutely, including a few best seen in binoculars.
Even so, don’t expect the field-filling spectacles of other seasons of the year. The summer, autumn, and winter skies have the Milky Way as the main attraction, replete with starfields rich in star clusters and nebulae ideal for binocular scanning. I presented my “Top 10 Tours” for those respective skies in the July/August 2022, November/December 2022, and January/February 2023 issues of SkyNews.
By contrast, in spring months the Milky Way is largely absent from our sky. Earth is turned so the northern hemisphere’s night side is looking up out of the disk of our galaxy to its North Galactic Pole (marked NGP on the photo here and on the chart I’ve included in this article) — a point not far from object #3 on my list: the Coma Berenices star cluster. Instead of seeing objects in the spiral arms of the Milky Way, we peer out of our galaxy towards distant galaxies beyond.
But all are small. In binoculars expect to see dim grey smudges at the limit of visibility. The thrill isn’t in the spectacle of the scene, but in the knowledge that mere binoculars are showing you objects whose light has travelled for millions of years (42 million in the case of Messier 65, the most distant galaxy on the list) to reach your binocular-aided eyes. Not bad for optics that might have cost just $200.
I observed all the targets with 10×50mm binoculars, though the galaxies on the list will certainly be more obvious in big 15×70mm binos.
But it isn’t just galaxies that inhabit the spring sky. We have two prominent star clusters: Melotte 111 and Messier 44. At only 313 and 610 light years away, respectively, both are nearby in our section of the galaxy — so they appear large and bright. And we have one globular star cluster, Messier 3, orbiting above the disk of our galaxy 33,000 light years away.
For variety, I have also included one famous double star, and a superb red giant carbon star. The tour ends with the most famous star of all, Polaris. But have you seen it as the jewel in a diamond ring of stars? Binoculars will show it! On with the tour!
The 10 tour targets
As with my previous binocular tours, I’ve processed the images here to better resemble the mostly monochromatic view in binoculars.
1. M44, the Celestial Beehive
Hunt down Messier 44 right at nightfall when it will be low in the west. It’s “off the chart” here, but the centre star chart plots it. In binoculars this bright splash of stars appears in the middle of a trapezoid of four stars. On June 2, Mars appears in the Beehive, followed by Venus on June 13.
2. M65 and M66, a Leo galaxy duo
Look within a seven degree binocular field below Chertan in the back end of Leo. I find Messier 66 to be the easier of the duo in binos, but both will be tiny glows, requiring a moonless night far from city lights — true of all the galaxies here.
3. Mel 111, best for binoculars
As one of the nearest star clusters, entry #111 in P. J. Melotte’s 1915 catalogue (the Coma Berenices cluster) is so large that binoculars will provide the best view. I see it as an inverted pentagon, with a nice double star, 17 Comae, east of its bottom apex.
4. M3, a binocular globular
While also a star cluster, Messier 3 is a globular richer than open clusters like M44, but much farther away. Look for a fuzzy “star” not quite half-way from Arcturus to Cor Caroli, a fine telescopic double star and the brightest star in Canes Venatici.
5. La Superba, a red star
Draw a line from Cor Caroli to Chara, Canes Venatici’s second brightest star, then turn 90 degrees left, or north. Within the field look for an orangey-red star, Y Canum Venaticorum. Dubbed La Superba by 19th century astronomer Fr. Angelo Secchi, it is a fine example of a giant star made red by carbon soot in its atmosphere.
6. Mizar and Alcor, a classic double
When you’re in the area, be sure to inspect Mizar, the middle star in the handle of the Big Dipper, and its widely separated companion, Alcor. With both at a distance of about 82 light years, they are likely associated — though not orbiting each other.
7. M51, the Whirlpool Galaxy
This iconic spiral galaxy 28 million light years away looks like a fuzzy star within a bino field below Alkaid, the end star in the Dipper’s handle.
8. M101, the Pinwheel Galaxy
At 23 million light years away, Messier 101, another classic face-on spiral, appears larger and more diffuse than M51. It forms a triangle with Alkaid and Mizar.
9. M81 and M82, a Great Bear galaxy pair
This is the toughest of the 10 to find. Draw a diagonal line from Phecda through Dubhe in the Dipper bowl and extend it about an equal distance away. Look for a pair of grey patches. Messier 81 — the spiral — is larger, while Messier 82 is the cigar-shaped irregular galaxy.
10. Polaris in the Diamond Ring
Aim at the North Star. Now look closely for a small circlet of stars below Polaris on spring nights — the asterism called the Diamond Ring, with Polaris the brightest jewel in the setting. This field simulates the view in 15× binos.
Background star chart courtesy StarryNight/Simulation Curriculum.