The National Park said it designed the event in 2017 to, in part, help local businesses towards the end of the traditional tourism season.
In Dunster, on the edge of Exmoor, the Yarn Market Hotel manager Antony Brunt said in recent years, “it has become much more widely known – and now we literally have people ringing us up to book”.
The hotel hosts special trips during the festival, led by a local astronomer, and runs visits to various sites and events across the park.
Brunt said the festival brings in people from all over the UK, adding: “It’s getting to a quieter time of year and these people, they really enjoy coming down.
“We have a group that come each year, in fact, twice a year. For people to come regularly twice a year to the same hotel, they must be enjoying the stargazing part of the weekend.”
The growing popularity of the festival meant that many events sold out before the opening day.