Observing in Ursa Major
When we look up at Ursa Major, the Great Bear, we’re seeing a constellation that barely rises above the horizon from much of the southern hemisphere. In cities like Sydney, Cape Town, or Buenos Aires, it’s a challenge to spot even a portion of it. But from mid-northern latitudes, Ursa Major is a year-round presence—one of the most easily recognized constellations in the sky, thanks to the prominent asterism known as the Big Dipper.
That familiar pattern of seven stars—Alkaid, Mizar, Alioth, Megrez, Phecda, Merak, and Dubhe—has featured in stories and sky lore for thousands of years. But the constellation holds more than myth: many of its stars are physically related, part of the Ursa Major Moving Cluster—a collection of stars that formed together and still travel through space in the same general direction.*
I was reminded of all this while during an observing session one moonlit night. The sky wasn’t ideal—washed out by city lights and a nearly full gibbous moon—but I set up my 203mm Dobsonian reflector anyway to take a look around.
Observing in Ursa Major
The Big Dipper hung just above the trees to the north, and I backed up against the shed to clear a view over the treetops. Even through the light pollution, I could make out all seven stars of the Dipper with the naked eye. I was particularly interested in Mizar and its faint companion, Alcor, which I could just distinguish. Alcor is about fourth magnitude, which told me I was seeing down to roughly that level unaided—probably my visual limit for the night.†
With a 32mm wide-field eyepiece in place, I turned the telescope toward Phecda, a second-magnitude star at the bottom of the Dipper’s bowl, on the side closer to the handle. Using the Telrad finder, I centered it in the eyepiece.
Phecda appeared bright and blue in the view—a color made easier to detect in stars of this brightness. Around it, a handful of fainter stars appeared mostly white. But what caught my attention was a distinctive little pattern near Phecda: three dim stars curving into a backward question mark, with Phecda forming the bright “dot” at the base.
Consulting my star chart, I could match the shapes: a 9th magnitude star close to Phecda, an 8th magnitude star forming the curve, and a 7th magnitude star at the top. A fifth, very faint 9th magnitude star made the pattern even more convincing. The match with the chart was solid—I knew I had the right spot.
According to the chart, there was a galaxy nearby—Messier 109, a barred spiral in the same general field. The chart showed that if I drew a line from the top of the question mark through Phecda and extended it the same distance on the opposite side, I’d land very close to M109’s position.
I nudged the telescope to that spot and scanned the view. But the galaxy didn’t show up.
Given the sky conditions, I wasn’t surprised. Although I could see stars as faint as 9th magnitude through the telescope, galaxies are more challenging. Their light isn’t concentrated to a point—it’s spread out over an area. Under bright skies, that diffuse glow just gets swallowed by the background. M109, although technically bright enough, was completely lost in the city skyglow and moonlight.
I tried averted vision, glancing just to the side of where the galaxy should be. Sometimes the more light-sensitive parts of the retina can pick up what direct vision misses. I lingered for a while, sweeping gently, letting my eyes adjust again. Still nothing. Tonight, the galaxy remained invisible.
I swung the view back to Phecda and the little question-mark asterism. There’s something deeply satisfying about those tiny patterns—casual arrangements of stars, many without names—that quietly decorate the sky. These informal constellations, seen through a telescope or with the naked eye, offer their own kind of beauty. I stayed with that view a while longer, taking it in, before finally packing up and heading inside.
~~~
* The Ursa Major Moving Cluster, Collinder 285, by the University of Arizona. Accessed 6 July 2025. https://web.archive.org/web/19991007030946/http://seds.lpl.arizona.edu/messier/xtra/ngc/uma-cl.html
†Magnitudes of astronomical objects are from Stellarium Mobile Plus, v1.12.9, by Stellarium Labs S.R.L. Accessed 6 July 2025, Google Play Store.