How Truman Researchers Measure Light Pollution Around Kirksville

Truman State researchers do not measure light pollution by simply looking up and deciding whether the sky seems bright.

The local research uses light sensors, an all-sky camera and automated monitoring systems at multiple locations around Kirksville and Thousand Hills.

The goal is to turn a subjective question — "How dark is the sky?" — into repeatable measurements that can be compared over time.

The monitoring network

DarkSky Missouri currently lists active sky-brightness monitoring sites at:

• Magruder Hall in Kirksville;
• Truman State Observatory;
• Thousand Hills State Park.

Those three locations provide a useful local contrast between campus/city conditions and darker surroundings.

DarkSky Missouri's current program says the meters continuously collect sky-brightness measurements for scientific analysis by Truman State University.

Sensors measure the brightness of the sky

A Sky Quality Meter or similar light sensor measures night-sky brightness in a defined part of the sky.

Repeated measurements allow researchers to look for patterns rather than relying on one especially clear or cloudy night.

The important part is consistency: if the instrument, location and method remain controlled, changes over time become more meaningful.

This article intentionally does not publish a homemade "Kirksville darkness score" because the underlying research has to be interpreted with the measurement method and environmental conditions attached.

Truman also uses an all-sky camera

Truman's Observatory research page says students use an all-sky camera as part of the light-pollution work.

An all-sky camera captures a very wide view of the sky.

That helps researchers see patterns that a single-point sensor cannot show as clearly, such as where bright sky glow is concentrated and how cloud cover changes the appearance of artificial light.

The camera and sensor measurements complement each other rather than answering exactly the same question.

Raspberry Pi systems help automate observations

Truman says some of its light sensors are controlled by Raspberry Pi microcomputers.

Other systems are designed for remote observation even where a normal power outlet or local wireless network is unavailable.

Automation matters because useful monitoring requires many observations across different nights and conditions. A system that can record consistently without somebody standing beside it every night produces a more useful time series.

Weather has to be part of the interpretation

Sky brightness is affected by more than artificial lighting.

Truman's research questions include the effects of:

• temperature;
• humidity;
• cloud type;
• different outdoor-lighting colors;
• shielding and fixture design.

Clouds are especially important because they can reflect artificial light back toward the ground and make a developed area look much brighter.

That means a brighter reading on one night does not automatically prove that more lights were installed.

Researchers can compare lighting changes over time

Truman has also studied how lighting changes affect sky brightness.

Its research page describes projects involving warmer-colored lighting and shields that keep more light directed downward.

The university reports grants totaling close to $15,000 for installing shields on problematic fixtures.

That creates a testable question: after a lighting change, do measurements show a meaningful difference under comparable conditions?

The answer should come from the data, not from assuming that any lighting project must have succeeded.

The network is still active

DarkSky Missouri's current measuring-sky-brightness page continues to list Magruder Hall, Truman Observatory and Thousand Hills as active sites.

It also invites institutions with their own Sky Quality Meters to register sites and offers a loaner program.

That makes the Kirksville work part of a broader Missouri monitoring network rather than an isolated campus experiment.

For what those measurements mean to an observer, see Kirksville Light Pollution: How Dark Is the Night Sky?.

For how monitoring connects with park management and certification, see Dark-Sky Efforts Around Kirksville and Thousand Hills.