Mills Observatory on Balgay Hill in Dundee was the first purpose-built public observatory in Britain and still opens its dome to the public, with a Victorian refracting telescope, modern instruments and displays on astronomy.

Leisure & Culture Dundee states on the observatory’s own page that “Entry to the observatory and use of all equipment is free, although donations are warmly welcomed”. Planetarium shows carry a small separate charge (GBP 3 adults, GBP 1.50 children), but looking through the telescopes costs nothing.

It runs a winter season from 1 October through to the end of March: Monday to Friday 4pm to 10pm and Saturday 6.30pm to 10pm, closed Sundays. Walk in on the night – but check their page first, as clear skies and volunteer cover vary.