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Hickson groups

ErikaRix
In 1877, French astronomer Édouard Stephan identified the first compact galaxy group. Astronomers now call it Stephan’s Quintet. Nearly two centuries later, Canadian astronomer Paul Hickson compiled a list of 100 such groupings while examining prints created using red-sensitive plates from the Palomar Observatory Sky Survey.

He based each group’s inclusion on its population, surface density, and isolation from other galaxies. While these gravitationally bound gems offer researchers opportunities to study galactic evolution, they also provide captivating views for backyard observers with large scopes.

For me, the real fun begins during the sketching process. The brightest members of any group are the easiest to spot, so the challenge is to locate and identify as many of the others as possible. At that point, we can study their unique shapes and draw them within the star field. I’ll break down the process with two sketches. The first shows Hickson 68, a tight, five-member group near the eastern border of the constellation Canes Venatici.

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