The sentence "countless stars" is correct and usable in written English.
You can use it in any context where you are referring to the countless stars in the sky. For example, "We looked up at the night sky and saw countless stars twinkling above us."
The law's passage proved a financial boon to the heirs of countless stars.
Vampiric soul-harvesters, they must sup on the extracted essence of another being: "a translucent shimmering globe, smaller than a pool ball, but cloudy with countless stars".
Here, in the distant future, would be intelligence; but there were countless stars before them still, and they might never come this way again.
Yet now he happily shatters the mystique of countless stars, breaking confidences and revealing all manner of embarrassing fetishes – whether for underage girls, smegma or voyeurism.
Countless stars and films have used it since, but it was her vision of the highs and lows of life, from the gutter to the glitter, that make it soar.
On a cloud-free night, countless stars and hurtling meteors are visible against a backdrop of the Milky Way that reaches across the sky from one horizon to the other.
"I'm sure I will hear from countless Star Wars fans who assure me that Episode II looks terrific, but it does not".
For those of you unfamiliar with the writings of Philip K. Dick, countless Star Trek episodes, or even Shrek Forever After - honestly, that's one I'm glad you missed - it's the idea that there's more than just the universe we sit in.
Jacqueline Onassis spoke about this phenomenon, as have countless movie stars.
Countless pop stars utter those words when they hit New York, but for few are they so absolutely true.
In an earlier epoch, Galileo had turned his telescope to the Milky Way and saw that it was composed of countless individual stars.
