led street lights to be installed across northern ireland - all in one solar street light
Northern Ireland will launch a plan to replace yellow sodium street lamps with LED alternatives.
At present, there are nearly 300,000 street lamps here.
About one in six people.
However, while they play a role in road safety and security, they also generate a large amount of light pollution.
Traditionally, street lamps appear in the form of yellow sodium lamps, but this is changing.
The Ministry of Infrastructure launched the pilot program in Banbridge and Armagh in 2015, which is currently being rolled out in Northern Ireland.
Officials say the new lights provide long term
Long-term savings in power use and maintenance costs-
And less light pollution.
So far, about 50,000 of the new lights have been installed.
But not everyone is happy.
Michael Burton, director of the Armagh Planetarium and Observatory, said that while new lights may make it easier for stars to see in urban areas, they pose new challenges depending on the type of LED used
"It's important to try to use what we call warm-colored LEDs that are in the red part of the spectrum," he said . ".
Light in the blue part of the spectrum-cool colours -
It's not good for eyes, he said.
"They don't adapt when you're outside, and you really don't see the stars," Mr Burton added . ".
"If it is in the red part of the spectrum, they will adapt and you can also see the stars and the streets.
"It's quite complicated.
Sodium street lamps emit all light at very narrow lines, very specific wavelengths.
Mr. Burton said: "At present, astronomers can filter out this light by taking pictures through binoculars.
"But now, with the broadband LED, you can't filter it out --
"So with the telescope, you will see the worse stars," he added . ".
"There is trade --
Introduction of LED lighting related products.
"Many lights are installed in residential areas --
Sleep experts believe this may adversely affect sleep patterns.
Lara Trainor, lecturer in medical sciences at Ulster University, said in the evening
Time exposed to LED lights can make sleep more difficult.
"It can affect melatonin in the body, which is a sleep hormone and plays a role in the circadian rhythm," she said . ".
"So you won't sleep if you are exposed to them.
She added: "It is very important for people to maintain good sleep hygiene;
They don't get exposed to light before they go to bed.
Whether it's a TV, a phone, a laptop or a computer screen.
"Also, they should have black if they are exposed to led lights --
To reduce the effect on the circadian rhythm, pull the curtains or blinds.
"Unfortunately, for homeless people or animals, they don't have that option, so it has a greater impact on them than the people who live in the house.
"About 20% of street lights have changed so far.
The Infrastructure Department said that future installations are closely related to the ever-tightening departmental budget.
So it may take a while for many of us to decide whether we are turned on or off by LED street lights.