This shot was taken yesterday with my long lens set-up of a 600mm astro telescope used as a prime lens with the 7D. I also use a 1.4x tc with the set-up. This gives 840mm which on the 7D gives 1344mm 'reach' on the 1.6 crop Camera.
The scope cost less than £300 so a fraction of the cost of a 600mm DSLR lens. Strictly manual focus and you need reasonable light.
This was shot from around 40 metres.