On the Way to Pluto: Messier 7

Caption NASA:"The New Horizons team calibrates the Long Range Reconnaissance Imager (LORRI) by taking pictures of the Open Star Cluster Messier 7 (M 7). This is the first LORRI image of M 7 taken during Annual Checkout (ACO); the 100-millisecond manual exposure was taken on June 25, 2010. A preliminary comparison of this image to a 2008 LORRI picture of M7 indicated no degradation or change in LORRI's performance".