... MAISON ( Multi-wavelength Astronomical Image Service On-line ) is a Web broker service which allows users to retrieve different images of the same field-of-view (FOV) from separate image servers. Through MAISON, users can readily preview a composite image created on-the-fly from these multiple images. ... Pointing observation images are searched for within a finite area on the sky centered at the users' specified location, thus generally have different FOVs. ... The image viewer . ...