Romantic Connor McLaren, 23, planned the occasion three months ahead so it would fall on the fifth anniversary of the day he met fiancee Jaimie McGregor, 29.
The sweet photos show the couple, from Perth, Perthshire, silhouetted against a myriad of stars on top of Glen Lyon, Perth and Kinross.
They went for a drive up the mountain at about 3am, which freelance photographer Connor had perfectly timed due to the light conditions required to see the Milky Way.
He had previously taken a picture of them holding hands, silhouetted against the starry sky, and knew how much it meant to Jaimie, who works in a jewellers.
He snapped up a ruby and diamond ring the shop was selling, and hid it for three months knowing she was disappointed it was no longer for sale.
But she was in the dark about what his plans were until the moment he got down on one knee, due to a ten-second delay on the camera which allowed him to get into position.
Connor said: “I’d taken a picture of us before, holding hands in front of the Milky Way.
“I told her I was going to try and do it again. It has to be at that time for the stars to be where they are.
“There is a rock formation called the Praying Hand, that’s where we went.”
“I had a ten second timer on the camera and got into position.”
The temperature was -2C, and the couple hiked for 40 minutes to get to the spot in the early hours of March 31.
They had met five years earlier, through a mutual friend, playing basketball, and got together as a couple about six months later.
Jaimie said yes immediately, but they have not yet set a date for the wedding.
Connor had secretly bought a ring which was for sale in the shop where his girlfriend works, knowing she had had her eye on it.
He told her boss of his plans to pop the question, and they came up with a story about how an old lady had bought the platinum ring.
Connor said: “When I brought it out she was totally shocked.
“I think she was surprised at how organised it all was.
“To take photos of the Milky Way, you can’t do it when the moon is out, or in summer when it is too bright, or in winter when it’s below the horizon.
“It all just went to plan and it was fortunate that the anniversary coincided with it.
“It was quite difficult hanging onto the ring and keeping it a secret for two months.”