|Messier 28 in Sagittarius.|
Its apparent diameter is a miniscule 11.2 arcminutes, making this also the smallest globular cluster by size on the sky that I've shown - the full moon would appear about three times as wide as this cluster. M28 has the distinction of being the second globular cluster where a millisecond pulsar was found (the first was M4, the first in my photo series). It is now known to contain 8 such pulsars. Other than that, I don't have too much to say about it.