The museum is situated in the former home of the Herschels at 19 New King Street (south side) in Bath, England.

The building is constructed from Bath stone ashlar, with some coursed rubble at the rear, and slate Mansard roofs with pantiling on the internal slopes.

The entrance is on the left-hand side of the building, which has three storeys, as well as an attic and basement, each of which have two sash windows.

[4] The building represents a middle-grade Georgian town house, typical of the homes of artisans and tradesmen of the city of Bath (but contrasting with Bath's grand visitor houses)[5] The Herschels moved into 19 New King Street in 1777,[4] at which point the builders would have still been present, and the road would have been unmetalled.

[5] William discovered Uranus whilst residing in the house in March 1781 using a 7 foot telescope designed and built in the attached workshop.

[3] The museum uses QR codes to provide translations of the display exhibit labels in 10 different languages,[12] and illustrated trails are available from the shop.

[4] The upper floors provided bedrooms and servant quarters;[5] they have subsequently been converted into flats.

The gallery was designed by Hetreed Ross Architects,[16] and is of a modern design,[17] with floor-to-ceiling glazing, overhanging eaves and a flat[18] stainless steel stressed skin roof,[19] with the solid walls constructed of Bath Stone Ashlar to match the rest of the building.

[23] The "Star Vault Astronomy auditorium",[15] opened in 2003,[8] shows a short film about the Herschels, their life living at 19 New King Street, and modern space exploration, narrated by Patrick Moore.

[25] A 1.25 m (4.1 ft) diameter powder-coated steel seed head by Ruth Moilliet represents Uranus's position in the 2005 Spaced Out model of the solar system, which spanned the UK with the Sun at Jodrell Bank Observatory.

Made of Bath stone and slate, it was unveiled in 1988 by Patrick Moore and Rod Davies.

[32] The museum also has a Thomas Butterfield sundial, dating from c.1690, made of silver in the shape of a bird, with names of European cities and their latitudes on the back; a Copernican Armillary sphere by George Delamarche, made of brass, wood and paper, and with Herschel's name and Uranus on one outer ring;[12] a Cometarium showing the motion of a comet on its path around the sun, on loan from the Science Museum;[33] and paintings of Elizabeth Baldwin by Robert Muller (pre-1798)[34] and John Herschel (1892).

[15] In 2015 it was announced that the museum will house Patrick Moore's collection of objects related to William Herschel.