The differences between galaxy and constellation are:
Galaxy | Constellation |
Galaxy is a huge assembly of stars, dust and gases held by strong gravity. | It is a group of stars from a fixed pattern and does not change their position with respect to each other. |
There are about 1011 galaxies in the universe. | There are only 88 constellation known so far. |
All the stars of galaxy revolve around a point called galactic center. |
There is no relative motion between the stars in constellation. |
There are unlimited number of stars within galaxy. | There are limited and fixed number of stars within each constellation. |