CHAMPAIGN COUNTY, Ill. (WCIA) — People in the rural areas of Champaign County recently got a glimpse of something unusual flying in the sky.

That something is a helicopter with a large apparatus hanging beneath it. As previously reported, the helicopter’s flights are part of an underground mapping project by the Illinois State Geological Survey to map the Mahomet Aquifer.

After a few weeks of delay, the project and flights started over the weekend. Several viewers sent in video of the helicopter in flight as it traversed the county.

The helicopter will fly over the rural areas of the county only, as the steel buildings of urban areas interfere with the magnetic charge the equipment emits.