TV astronomer Heather Couper has died aged 70 following a short illness, her best friend and business partner said.
Dr Couper made regular television appearances including on shows such as The Sky At Night, hosted by Sir Patrick Moore, and also presented the 1981 children's series Heavens Above.
Fellow astronomer Nigel Henbest described his friend as "charismatic".
He said the 70-year-old would be remembered as a "passionate communicator of science".
Dr Henbest described being at Dr Couper's bedside when she died.
He said: "She basically just faded away peacefully so it was a classic case of she died peacefully in her sleep after a short three-week illness."
Dr Couper died on Wednesday morning at Stoke Mandeville Hospital in Aylesbury, Buckinghamshire.
In 2007, she received a CBE for services to science.
She was also a radio presenter, served as a Millennium Commissioner and was the first woman president of the British Astronomical Association.
Dr Couper and Dr Henbest worked and lived together.
They co-authored Philip's 2019 Stargazing Month-By-Month Guide To The Night Sky Britain And Ireland.
The pair met while at the University of Leicester, where Dr Couper studied astrophysics before moving on to the University of Oxford.
She later became president of the British Astronomical Association and Gresham professor of astronomy.
Paying tribute to the broadcaster, Dr Henbest said: "When she enthused people about astronomy and space, she was charismatic.
"There's one word to describe her, that was charismatic. She had a bubbly personality.
"She got people really excited about the universe and about space - that was her love, her passion in life."
He said she loved looking at the sky as something wonderful and wanted "to give people a cosmic vision to know and appreciate the earth".
Additional reporting by PA.
