© ReutersThe comet was officially registered with the centre and given the name C/2013G9 (TENAGRA)
They focused their study on a space object that had been observed before as a possible asteroid but its classification had not been formally noted.
After studying the data, the group were able to rule out the space matter as an asteroid but also anything that had previously been discovered.
The Year 11 pupils sent off their analysis to the Minor Planet Centre in Massachusetts and were amazed to be told they had discovered a new comet.
The comet was officially registered with the centre and given the name C/2013G9 (TENAGRA).
Teacher Paul Campbell, a keen amateur astronomer, said the group couldn't believe they had managed to discover the new space object.
"The students are absolutely buzzing they just can't believe it," he said. "When we started this project never in their wildest dreams did they think they would discover a comet.
"There are a few teams around the world using these telescopes but there was only one comet discovered in March so it is really quite a rare event to discover something new.
"It had been observed earlier as a possible asteroid. But we did some checks and reduced the data which ruled out any object which had already been discovered."
Mr Campbell added: "They will be sitting their exams in four weeks time so it's a great boost for them."
The students made the find the final weekend for their GCSE project.
asteroid turned comet, perhaps?