Top panel: spectrum of water clouds on Earth. Bottom panel: spectra of Enceladus (both the leading and the trailing hemispheres are indicated with blue and red colours, respectively) and Eris (black) from Verbiscer et al. (2006) and Alvarez-Candal et al. (2011), respectively. The visible spectrum of Enceladus is not shown, but the geometric albedo is known to be 1.375 (Verbiscer et al. 2007). Yellow vertical bands indicate the full widths at half maximum of the V, R, I, J, H and K photometric bands. The green vertical band indicates the F140M filter band where the cloud spectrum is low but the water ice spectrum is relatively high.