Messier 94 (RGB)

Galaxy season is so much fun this year having access to longer focal length telescopes compared to the last two years. I love my little 80mm refractor but it is not a great choice of galaxies.

This is Messier 94, a spiral galaxy in Canes Venatici. It’s about 16 million light years away which makes it fairly close in galactic scales. It’s apparent size is relatively large compared to most galaxies but it’s still pretty small at only about ⅓ as wide as the full moon.

This galaxy has a face-on orientation to us and is unusual because of the other ring surrounding the disk. Astronomers have ruled out it being caused by a merger. Instead they think something warped the disk which caused the resonance to form in the rotation periods between the inner and outer portions of the galaxy and it is that which caused the ring.

Whatever caused it, it’s an unusual sight to see — an entire galaxy doing a Saturn impersonation!

M94 is unusual in another way though this one isn’t visible to us in this image. It’s almost devoid of dark matter. We can’t detect dark matter directly but we can detect its presence by measuring the rotation rates of stars at different points int he galaxy. That lack of dark matter actually makes the case for dark matter stronger…sort of a case of the exception proving the rule.

You can find the technical details at astrobin.

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