Many (or at least a few) Moons Ago ! There was some forum chat discussion about UK maps.
These days I'm only an armchair stargazer (excepting the Sun) & armchair hill-goer. However although I think really genuine stargazers are relatively few in number, it seems some are enthusiastic about going into the hills to dark locations (even if mostly roadside car parks) but a few camp on mountain tops.
There are nowadays several hill-going monthly magazines which occasionally include articles about mountain top stargazing. Obviously hill -going stargazers need suitable navigation tackle - such as map & compass, torch and adequate clothing.
"Trail" May magazine includes an interesting article page 66 about the most popular UK maps - 1:50,000 Landranger, !:25,000 Explorer, Ordnance Survey Maps and Harvey's 1: 40,000 British Mountains, 1:25,000 Superwalker & 1;12,500 maps.
Trail May mag article also includes a warning - "Tourist features in blue (nature trails, visitor centres and importantly ski-lifts) are not placed accurately on any of the above maps. They should NOT be used as navigational aids."
Oh! I nearly forgot there is a "free" 100 page Gear Guide 2017 with the May Trail magazine which probably includes some clothing suitable for enthusiastic stargazers - but not cheap!
Best wishes from Cliff