Big Jim On Alpha.

Yes, I'm a Space: 1999 fan. Why did you ask?

From YouTube here's the opening sequence from the first season episode "The Troubled Spirit." This music, parts of which is used elsewhere in the episode, is performed by well known British session guitarist Big Jim Sullivan, who appears as the musician playing the music on Moonbase Alpha. The instrument used is a Coral Electric Sitar, a guitar designed to have a sitar like sound. It was created by the Danelectro guitar company in the mid '60s with the help of New York sessioner Vinnie Bell to cash in on the Indian music fad launched by Beatles' recordings like "Norwegian Wood."

The episode is a good example of the often gothic and psychedelic feel of the first season of the series. Chaos is unleashed when an attempt to communicate with plants(plant intelligence being an idea popular when the episode was made, now long debunked) causes Alpha scientist Dan Mateo's vengeful spirit to haunt Alpha before Mateo's death.