Messier 3 (M3; also NGC 5272) is a globular cluster of stars in the northern constellation of Canes Venatici.

[1] M3 has an apparent magnitude of 6.2,[9] making it a difficult naked eye target[13] even with dark conditions with averted vision.

However, with a moderate-sized telescope, the cluster can be seen as a cloudy smudge even in severely light-polluted skies, and can be further defined in darker conditions.

Using a telescope with a 25 cm (9.8 in) aperture, the cluster has a bright core with a diameter of about 6 arcminutes and spans a total of double that.

The overall abundance of elements other than hydrogen and helium, what astronomers term the metallicity, is in the range of −1.34 to −1.50 dex.