Point a telescope at a good star cluster and it looks like a crowd that has just been called to order: dozens of stars, all gathered in one spot, waiting for the show to begin.

The design: everybody in, take your places

Seven navy stars of different sizes lean in around an empty conductor's music stand, as if a choir were assembling for roll call. Below, CLUSTER MUSTER is set in tall navy capitals. A muster is a gathering of a group, and a cluster is the sky's own gathering of stars.

For Messier nights and club meetings

Wear it to a Messier marathon, a club star party or an evening with binoculars sweeping the summer Milky Way. It is a cheerful gift for the friend who logs clusters, sings in a choir, or both.

The tee: why it costs a little more

This shirt is a step up from a basic tee. It feels soft and broken-in from the very first wear, has a little more weight so it drapes nicely, and breathes well on mild nights. It is dyed after it is sewn, which gives each color a relaxed, lived-in look, and the reinforced neck and stitching help it last for years of wear.

• 100% cotton, soft from the first wear.
• A little thicker than a basic tee.
• Unisex relaxed fit — size down for a closer fit.
• Dyed after sewing for a lived-in color.
• Reinforced neck and shoulders help it keep its shape.
• Double-stitched hems for everyday durability.
• The full design is printed on the front; the back is plain.

Quick answers

What is a muster?

A muster is a gathering where a group comes together and is counted. The shirt borrows the word for star clusters, where dozens of stars are gathered in one small patch of sky.

What's the difference between open and globular clusters?

Open clusters, like M35 in Gemini or the Double Cluster in Perseus, are loose groups of a few hundred young stars in the disk of our galaxy. Globular clusters, like M5 in Serpens or M92 in Hercules, are tight balls of hundreds of thousands of very old stars orbiting in the galaxy's halo. A good Messier list mixes both.

Why a conductor's stand?

It turns the cluster into a group being called to order, like a choir taking its places before the music starts.

Which clusters would suit a first look?

Bright favorites such as the Pleiades (M45), the Beehive (M44) and the great globular cluster M13 in Hercules all look lovely in binoculars or a small telescope.

Care

Machine wash cold, inside out, on a gentle cycle with similar colors. Skip fabric softener and use non-chlorine bleach only if needed. Tumble dry low or hang dry. If you iron, use a cool iron on the inside and keep it off the print. Do not dry clean.

Shipping and returns

Free US shipping. US delivery usually 5–12 business days. Easy 30-day returns.

Size guide