MLA

Richards, John Inigo, 1731-1810, artist. [Sir William Herschel exhibiting his great telescope to George III at Slough 1782] [art original].. [approximately 1782]. https://collections.library.yale.edu/catalog/11138701.

APA, 6th edition

Richards, John Inigo, 1731-1810, artist. ([approximately 1782])[[Sir William Herschel exhibiting his great telescope to George III at Slough 1782] [art original].]. https://collections.library.yale.edu/catalog/11138701.