Eleven years after its perihelion , comet C/1995 O1 ( Hale-Bopp ) is still active .
Between 2007 October 20 and 22 , we detected a diffuse coma of 180 \times 10 ^ { 3 } km in diameter with a slight elongation toward the north-south direction .
The integrated brightness was 20 \fm 04 in R _ { C } , implying Af \rho = 300 m and albedo \times dust surface a _ { R } C = 4300 km ^ { 2 } .
The coma was relatively red at V - R = 0.66 mag , which is consistent with that of the dust in other comets .
The observed properties and the overall fading in brightness between 10 AU and 26 AU follow the predicted behaviour of CO-driven activity .
This is the most distant cometary activity ever observed .