NGC 5194, NGC 5195- Whirlpool Galaxy
As one studies these 2 overlapping galaxies, one senses there is a history between the two that goes way back…indeed, according to some of the more current dynamic models (Salo 1999), NGC 5194 (M51A), the large tightly spiraled galaxy, and NGC 5195 (M51B), the distorted irregular, have passed through each other more than once. It is believed that their first encounter occurred about 500 million years ago as the larger 51A passed from behind. This encounter helped create the very tight spiral formation of 51A, and also disturbed the former disk of 51B, creating a more irregular shape. The model shows the galaxies dancing around till about 50 million years ago, when they repeat their crossing, this time with the larger 51A moving through 51B away from the observer. The 2 galaxies together are referred to as the “Whirlpool Galaxy”, and lie about 23 million light years away. 51B is currently some 50,000 ly behind the larger 51A.
Image Acquisition info:
Location: Starlodge Observatory
Camera: SBIG STL 11000
Scope: Planewave CDK 12.5