There is an art museum standing in Geiger Memorial Park in Deer Park right now. It has no walls, no ticket desk and no closing time other than the park's own, and it will be gone after October 4. Then the whole thing packs up and moves to Heckscher Park in Huntington, where it reopens October 9, the same weekend the Long Island Fall Festival fills that park with its rides and food rows.

What is actually standing in the park

The installation is the Long Island Public Arts Festival, a touring outdoor exhibition that turns public parks into what its organizers call wall-free museums. The works are not murals and not sculptures in the usual sense. Original pieces by New York State artists are enlarged into six-foot-square exhibition displays and mounted on freestanding three-sided structures the festival calls prisms, placed along the park's walking paths. More than 50 artists are represented across this year's tour. Viewing costs nothing and follows regular park hours: walk in, wander the loop, leave when you want.

The effect is deliberately different from an art fair. Nobody is selling from a tent, and there is no schedule to plan around. The art simply stands where the park's regulars already walk their dogs and push their strollers, which is the point the festival was built on: bring the work to people who were not planning to see art today.

A Babylon-born idea in its biggest year

The festival started as a Town of Babylon project, developed by the Babylon Citizens Council on the Arts together with artists Harper Bella and Jose Tutiven, through funding from Creatives Rebuild New York. Its first home was Phelps Lane Park in North Babylon, which it transformed into an immersive outdoor exhibition and where this year's tour ran from July 1 through August 9.

This season is the first time the idea has traveled. After Phelps Lane, the exhibition arrived September 1 at Geiger Memorial Park off Grand Boulevard in Deer Park, newly renovated and getting its first run as a cultural venue. The Deer Park stop is on display through October 4. The festival is curated by the arts council with Colored Colors, the creative studio Tutiven founded, and is supported in part by a grant from the Suffolk County Office of Cultural Affairs.

The Heckscher finale, timed to the Fall Festival

The tour's last and largest stage is Heckscher Park, at Prime Avenue and Main Street in Huntington, from October 9 through November 1. The timing is not an accident. The Long Island Fall Festival, which runs October 9 through 12 in the same park, draws one of the biggest crowds Huntington sees all year, and the exhibition opens in partnership with the Huntington Township Chamber of Commerce to meet it. Anyone coming for the festival weekend will walk through the exhibition on the way to everything else, and the art stays for three more weeks after the rides leave.

Why this is worth a detour

Long Island does not lack for art, but almost all of it lives indoors, behind admission desks, in Nassau's museum row or the North Shore's historic estates. What it has rarely had is contemporary work by living New York artists standing free in a South Shore town park, viewable at 7 a.m. with a coffee or at dusk after practice. Deer Park, of all places, has it first this fall. Huntington gets it next month.

The practical details are as simple as they come. Geiger Memorial Park, Grand Boulevard in Deer Park, through October 4. Heckscher Park, Huntington, October 9 through November 1. Free both times, open whenever the parks are, and gone by the second week of November.