The phrase "a constant sight" is correct and usable in written English.
It can be used to describe something that is frequently seen or always present in a particular location or context.
Example: "The old oak tree has become a constant sight in the park, drawing visitors year after year."
Alternatives: "a regular occurrence" or "a familiar view".
On street corners, there are relatively few if any police officers manning foot patrols, as was a constant sight during the Bloomberg years.
Bottles of conquered spirits, cider and six pound Prosecco will adorn the shelves in your room like sporting trophies, drum and bass will keep you awake til the early hours of the morning and leftover pizza boxes will be a constant sight in the communal kitchen purely for the delectation of the local vagrant population – mostly made up of freshers with hangovers.
For two or three or four weeks at a time, the men — and a few women — of this tugboat business live in constant sight of the flashing red light atop the Empire State Building and 1 World Trade Center's red-and-white sparkle, but they rarely, if ever, set foot in Manhattan.
Something about the constant sight of the attentive faces -- hundreds, often thousands, a day, all wearing that strange, slightly goofy smile that celebrity evokes -- persuades them that everything they say is worth chiseling in marble.
Today, van Herpen works within constant sight of water.
Around 8 p.m., after eight hours of nonstop activity, the constant sight of people doing the two things you wanted to do most but were forbidden from doing — sitting down and eating — would become a torturous sight.
Constantly being attached to our smartphones may now mainly affect our relationships with other halves, who are frustrated at the constant sight of our scalps.
A cinder-block cube with a flat-slab roof, the storm house stood ten feet from the back door of their home, practically beneath the kitchen window; the constant sight of it was either grim or comforting, depending on one's world view.
It's full of so much technology and innovation that people may be blinded by the constant sight of trails being blazed.
One challenge with such an approach is the requirement to maintain a constant line of sight between the light sources and the detector, which may be unrealistic in some clinical scenarios.
David Attenborough has his blue shirts – originally used so his shows would have continuity, but which now are a constant in almost every sighting of him.
