English: The two images on the left are actually the same image displayed indifferent ways. In the top-left image, the Masubi plume is too dim to be seen. The bottom-left image has been processed to enhance the visibility of the plume, which can be seen rising above the bottom-left edge of Io's disk. This processing overexposes the surface of Io so it appears completely white. In the pair of images on the right, a second image has been processed in similar fashion, so that Io's surface features are visible in the top-right image and are overexposed in the bottom-right image. This time Masubi is on the night side of Io, just beyond the terminator (the imaginary line separating day from night), but the plume is high enough that it extends up into the sunlight. A plume from the volcanoPrometheus can also be seen in this image, rising above the left edge of Io's disk. The diagonal line in the bottom-right image and the small bright spots sprinkled across all the images are caused by charged particles hitting the camera's CCD (charge-coupled device) detector. North is to the top in all the images. The images on the left were taken by the on August 14, 1999 at a range of 1.1 million kilometers (700,000 miles) and have a resolution of 11 kilometers (7 miles) per picture element. The sun illuminates the surface from behind the spacecraft. The images on the right were taken on August 14, 1999 at a range of 1.6 million kilometers (1 million miles) and have a resolution of 16 kilometers (10 miles) per picture element. The sun illuminates the surface from the left.