The International Space Station is a difficult object to image at this scale.  Consider the fact that the ISS is about the size of a bus, 230 miles away (NYC to Wash. = 205 miles) and traveling at 14,000 mph.  For reference, this is the same image scale as my Mars, Jupiter and Saturn photos.  The ISS also presents a different perspective as it passes over, much like an airplane.  Of the 300 images I took over one minute, only 8 ended up in the field of view. 

Another view of the International Space Station, taken on May 18, 2005.  As you can see, this is a larger image scale than the previous shot.  This image was captured using a Canon 20d digital camera attached to the telescope.  The focal length used was 6,400 mm with a 1/100 sec. exposure at ISO 1600.   For both images, I manually moved the telescope while tracking the satellite.  This is going to take a lot more practice.