M90 is an intermediate spiral galaxy in the Virgo Cluster and located around 60 million lightyears away. It is significantly larger than our own galaxy, with a diameter of approximately 160,000 lightyears.
It is unusual in that it is approaching us at a velocity greater than the oppositely directed cosmological recession velocity.
In addition, while there has been recent star formation in the inner spiral arms, the outer parts have been depleted of an estimated 90% of their neutral hydrogen. This was caused by intracluster ram-pressure stripping, as it passed through the centre of the cluster around 300 million years ago. This has resulted in a diffuse and partially ring-like structure in the outer regions of the galaxy.
The smaller galaxy to the left of M90 is irregular galaxy IC 3583, around 30 million lightyears distant.
This image is the result of 5h15m of RGB data capture from Horsham, over five evenings in April 2025. A ZWO ASI2600 MM Pro camera was used, through an 8-inch Teleskop-Service Ritchey-Chretien reflector.
Date: 19/04/2025
Location: Horsham, West Sussex
Photographer: Graham Wilcock
