"I didn't try to act like a smart ass, I just didn't know,'' said the former airport baggage handler.
He said he feels he has been made an example of but hopes others will learn from his mistake.
"Just be careful. I could go outside and point a laser right now but as soon as a plane comes by its an offence.''
He said lasers were widely available, and his was bought at a local shop.
Judge Charles Blackie told the court he was surprised that there were no restrictions on selling the lasers, that are about the size of a ballpoint pen.
The court heard how Chandra pointed his laser at three commercial aircraft as they made their final approaches to Auckland Airport.
Judge Blackie said pilots only have dim lights inside the cockpit so they can still see outside for any hazards.
"A flash of green light, as you aimed at the aircraft, causes a brilliant illumination in the cockpit and affects their ability to see.''
He said not only did Chandra endanger those inside the plane but also the people of south Auckland who live and work in the plane's flight path.
Judge Blackie said one of the pilots described Chandra's laser as an "actual danger'' to the aircraft and passengers onboard.
And when the police Eagle helicopter went to investigate, it was also struck by the laser.
"So all told, the lives of over 600 people were put at risk by your use of a laser which had no useful purpose to you at all,'' Judge Blackie said.
Earlier, Chandra's lawyer Hermann Retzlaff said his client had approached the pilots to apologise.
"He himself admits it was reckless and foolish behaviour.''
Mr Retzlaff also asked that Chandra's youth and his previous good record be taken into account.
In sentencing, Judge Blackie said he believed a sentence of imprisonment should be imposed to send a "message'' but he reduced that on account of Chandra's age and his early guilty plea.
"If other people think that it is appropriate to use these devices with aircraft in mind as a target, they will face the full term of a custodial sentence.''
As well as sentencing Chandra to home detention, Judge Blackie ordered the destruction of the laser and that Chandra complete any courses that his probation officer thought were appropriate.
The New Zealand Airline Pilot's Association president Glen Kenny said the sentence sent a clear message.
"Laser strikes are not just an attack on the pilots; they are an attack on the travelling public and can at best be described as reckless and dangerous.''
He said at best laser strikes are a distraction, and at worst they can cause temporary blindness or even permanent eye damage which is extremely dangerous if the aircraft is preparing to land.
``Laser strikes are a trend that has increased over the past couple of years, and it's now high time the Government addressed the issue and introduced regulations on the sale of these devices and a public education campaign.''
A spokeswoman for the associate Minister of Health Jo Goodhew said officials had prepared ``options'' for public consultation later this year. Asked if one of those options involved the banning or restrictions being put on lasers, she said she could not comment on the detail.
Air New Zealand has called for a New Zealand-wide ban on hand-held lasers in the wake of the sentencing.
Airline operations manager David Morgan said the current legal penalties were not deterring people from pointing hand-held lasers at aircraft.
He said a ban on class 3 green-light laser devices would bring New Zealand into line with Australian legislation.
"Failure to act to ban these devices runs the real risk that a thoughtless and reckless individual could cause an air accident."
Laser pointing had the potential to distract pilots, limit their night vision and potentially cause eye damage, Mr Morgan said.
Laser strikes happen during the critical stages of take-off and landing, making the practice more dangerous, he said.
LASER CASES
* Joshua O'Hare-Knight and James Spiers each face a charge of unnecessarily endangering an aircraft. They are alleged to have pointed a laser at the police helicopter while at a teenage party last year
* In March 2011 a 17-year-old was charged with reckless disregard for the safety of a police helicopter after he pointed a green laser at the Eagle helicopter
* A 19-year-old was charged with endangering transport after aiming a laser pen at the police helicopter in December 2010. The charges were dropped because of the accused's "good character" and personal circumstances
* Vladimir Maricic aimed a laser he bought over the internet into the cockpit of a plane near Wellington Airport in 2008. Maricic said he was trying to see how far the laser would reach. He was sentenced to 200 hours community service.
