Small City, Bright Lights

This article is the first in an occasional series we're calling Southington from Space, where we explore what we can learn about the town from far above, using satellite and aerial imagery, as well as other public data.

Have you looked up at the stars lately? You might find the Big Dipper looks fainter than you remember. Can you see the Milky Way?

Maybe you went outside last year to try to see the aurora borealis from the Novick nature preserve or Comet Tsuchinshan-ATLAS from the Long View Cider House hill?

Southington, like much of the country, is losing its dark night sky to light pollution.

The constellation Orion, as seen from Southington in 1999 SCOTT GRISWOLD PHOTO

Satellites can detect nighttime lighting from space. VIIRS, a special camera carried by the Suomi satellite, has measured the intensity of light at every location on earth every night since 2014.

From orbit, the town of Southington appears somewhat darker than its more urban neighbors, but brighter than its rural neighbors. To the east of town, you can see a very dark patch over the Hanging Hills between Berlin and Southington. To the west of town, the Waterbury mountain is also quite dark.

VIIRS pixels show the intensity of light; yellow areas are brightest. (Dec. 2014) JILL R. KELLY MAPS

The light that reaches VIIRS from the landscape comes from streetlights, business lighting, and household outdoor lighting. VIIRS can even detect an increase in brightness around Christmas, as Christmas decorations light up the sky!

Artificial light that reaches the sky is called "sky glow." It is most noticeable on a cloudy night, when the sky looks yellowish-gray rather than deep black.

In this VIIRS image from December 2024, you can see Southington's business districts, brightly lit.

Close-up, the business districts of West Street and Queen Street (shown in blue, with I-84) clearly have the brightest lights.

Nighttime lighting is often thought of as a good thing. Streetlights can make roads safer for cars and pedestrians, as long as they are not so bright that they cause glare.

Parking lot and residential outdoor lighting is often credited with reducing crime. People tend to feel safer in brighter outdoor areas, so brighter areas attract more visitors, which in turn might make them safer. We also often perceive brightly lit residential areas as well cared for.

Economists like to use the VIIRS nighttime lights images to study rural electrification and economic development. As new businesses open, their parking lots and lit signs add more light to the area. Scientists can compare two VIIRS images from different dates to learn where nighttime lighting is expanding. Even investors sometimes use this kind of analysis to understand which areas are growing economically, and which are declining.

Each decade, Southington becomes brighter as it grows in population and develops its commercial landscape.

Compare Southington's nighttime lights in 2014 (left) with 2024 (right). Commercial districts have both expanded in area and become much brighter. The switch to LED lighting has also had an effect.

This map shows the changes from 2014 to 2024, with hot pink indicating the greatest increase in brightness occurred near Queen Street and West Street.

While nighttime light can indicate economic growth and contribute to public safety, brighter nights are not entirely beneficial.

"Animals like moths can have difficulty adapting to artificial nighttime lights," said Peter Picone, a wildlife biologist with the Connecticut Department of Energy and Environmental Protection. "Moths may be lured by bright lights to buildings where they are easy prey for birds when morning comes."

Craig Repasz, a founder of LightsOutCT, says that birds also struggle with nighttime lighting, particularly during migration season. "Two billion birds are killed in North America every year because they fly into glass windows. Many of these window strikes occur at night, when windows of buildings are lit from within. Birds see into the room and mistakenly think they can fly there." According to Repasz, half of these window collisions occur in residential neighborhoods.

Outdoor lighting presents a complex danger to birds, Repasz explained. Sky glow from bright commercial areas can confuse birds, causing them to descend from their migratory flights as if dawn is near. Looking for a place to roost, they fly low among buildings, which puts them at risk for window collisions.

Repasz suggested that, in addition to turning off nighttime lighting during bird migration seasons (fall and spring), both residents and businesses can put bird-safe stickers or mesh on their windows to prevent collisions.

Repasz stressed that wild animals are not the only beings at risk from excessive nighttime lighting: human health can also be damaged. Studies have linked increases in cancer and diabetes to outdoor artificial lights at night.

So how do we manage these tradeoffs? There is one more important fact to know about nighttime lighting: any light that actually reaches a satellite in orbit is wasted. A bright light that shines up into the sky is not shining where people can use it. It's not just an annoyance to stargazers or a danger to birds; it's a waste of electricity!

Dark Sky International suggests five principles for responsible outdoor night lighting:

(1) It should be useful, placed only where it is needed.

(2) It should be targeted, aimed and shielded to shine only where needed.

(3) It should be no brighter than necessary.

(4) It should be turned on only when needed.

(5) It should be warm in color.

Residents can take steps to make their neighborhoods darker at night. You can commit to turning off outdoor lighting and closing curtains, shades or blinds during bird migration seasons. Businesses can also turn off interior lights and choose outdoor fixtures with "cut-off" shielding caps that direct light downwards.

But individuals struggle to limit light pollution from nearby businesses or in natural areas. Several Connecticut towns have adopted night-lighting laws. Greenwich, which has the state's most stringent regulations, holds nighttime lighting levels to different standards in different zones. According to Repasz, a Hamden resident, Hamden's building code requires downward-facing lights and forbids "light trespass," any light that disturbs neighboring property.

Southington's nighttime lighting regulations also vary according to zone. "Age-restricted cluster housing," for example, requires "fully shielded, Dark Sky Compliant, LED fixtures," while business zones only require lighting to "be arranged so that the lights will not . . . cause a nuisance from excessive glare. Full cutoff fixtures with recessed lenses only shall be required unless the applicant specifically requests an alternate lighting fixture." In a mixed-use zone, "all lighting shall be full cut-off style, dark sky compliant LED fixtures." Light is restricted from spilling off premises, and site plan applications require a "photometric plan" component.

Careful restraint in the placement, shielding, time-of-use, intensity and color of lighting can reduce harm to wildlife and human health, while preserving safety and our enjoyment of the nighttime sky.