Have you been looking skyward in the evening hours and been intrigued by a bright light in the western sky? You're not alone.

Although it's simply the planet Venus on its evening cycle, the Adelaide Planetarium has reported a number of callers concerned the unusually bright planet may be a supernatural occurrence.

"We have had some UFO calls," said resident astronomy educator Martin Lewicki.

Mr Lewicki said those who ventured out into the bush on a 'dark, moonless night' could easily be fooled into thinking the brightly lit planet was moving.

"Usually you can't see the horizon very well and Venus can look like its moving," he said.

"It sounds dramatic, but all sorts of mind tricks can occur."

The planet has been dominating the night sky since April and Mr Lewicki said people tended to forget it can appear in both the morning and night skies, depending on its cycle.

"There's a 19-month cycle where it returns to the evening sky for about ten months and then it disappears and goes into the morning sky," he said.

"People who've been missing it in the evening forget how bright it was and are amazed by it when they see it again."

In the state's South East, Mt Gambier resident Judy was coming home from work on Monday night and said she noticed an unusually bright star which appeared to be quite close.

She at first thought it was the international space station, after hearing it could be within range.

Judy said by the time she went to bed at around 11pm, the star had moved to just over the rooftops in the Western sky and she was curious about it's origins.

Aaron Seymour from Penola also had his interest piqued by the bright light in the night sky, reporting he was able to photograph it with his mobile phone, which barely picks up a full moon.

Mr Lewicki said both sightings were almost certainly Venus as the international space station would move across the entire sky in around four or five minutes.

He said the planet illuminates so brightly because of its close proximity to earth and its full cloud cover.

"It's covered entirely by cloud, which is a good reflector of sunlight and because its closer to the sun than earth, it receives twice as much brightness from the sun."

"All of that adds up to produce a rather bright object in the sky."

Mr Lewicki said the Planetarium get plenty of calls around this time, with most just inquisitive as to what it might be.

He said cloudy nights can sometimes produce a trick image for the eye, blurring the light and making the planet appear larger than it is.

Those lucky enough to have good quality binoculars, Mr Lewicki recommended to track the planet, and be rewarded with a lunar show.

"You can see it's phases, very much like the phases of the moon.," he said.

"At the moment it looks like a half-moon, in the next few weeks it will come closer and look larger and gradually migrate into a crescent phase.

"Then it will dip down towards the horizon and disappear from view by the end of the year."

Whereupon it will become an evening star and repeat the whole thing in reverse, in the morning sky for another 10 months."

"But it's been doing that for millions of years."