View of Windsor Castle from Slough House.

The Herschel family home in Slough, Observatory House, was chosen for its relatively close proximity to Windsor Castle since William could be called upon at any time of day or night to take his telescopes to the palace to show the Royal Household the stars.

By 1827 William was dead and Caroline had returned to Hanover while John and his mother remained based at Slough. This watercolour was done by Matilda Parry, sister of the arctic explorer William Edward Parry, whom John FW Herschel appears to have met through their mutual involvement with the Royal Astronomical Society. John was also an occasional correspondent of William and Matilda's elder brother, the physician Charles Henry Parry.

The drawing is inscribed on reverse: 'Taken by Mis Matilda Parry from my Bed room window in 1827 MB (Mary Baldwin)'