On supporting science journalism
If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.
Australian IT specialist Terry Lovejoy moonlights as an amateur astronomer with five comet discoveries under his belt. His latest find, Comet C/2014 Q2 (Lovejoy), is currently approaching the sun, making it visible for the next few days to naked-eye observers in the Northern Hemisphere with clear skies in the early evening. The comet has gained social media fame, with eager stargazers around the world seeking it out. The attention has surprised Lovejoy, whose earlier discoveries didn’t get near as much attention. “This time it’s been quite insane,” he says. “In the last week and a half I’ve had at least a thousand Facebook friend requests.”
Lovejoy found his first comet in 2007. His third discovery, made in 2011, was distinctive because it was what is known as a Kreutz sungrazer—a comet that literally grazes the atmosphere of the sun. That object, called Comet C/2011 W3, flew through the sun’s corona, passing within 140,000 kilometers of the solar surface, and emerged damaged but still intact.
Scientific American spoke to Lovejoy about his comet-hunting exploits and his advice for those who would like to follow in his path.
[An edited transcript of the interview follows.]
How long does it take you to find a new comet?
I probably get one every two years. It doesn’t sound like a lot but it is quite tough. I’m trying to improve those odds with equipment upgrades and software changes.
Most comets are discovered by the professional surveys. We amateurs tend to find stuff in areas near the sun where the surveys don’t look.
How do you do it?
The computer and the telescope do most of the work. I have a shed just on the side of the house here; it has a roll-off roof that I can just push off. Then I connect the telescope to the computer and I run an automated sequence to image parts of the sky.
It takes three images of the same part of the sky, but they’re separated by about 10 minutes. If there’s a comet or any moving object you’ll see it move between those exposures. I have software that basically trawls through those images and looks for objects that are moving. What I do by eye is I look at what it’s found to verify if it’s real or not. That’s how I’ve done the last two.
Before that I looked at the whole image manually; it took a long time. A couple years ago I had to start automating it. Now it takes five minutes to do what used to take two to three hours.
A few people had pictured me being out there all night looking through a telescope. That’s very old school—it doesn’t happen. I have a family, I’ve got two kids, my wife. I have to think about them.
How often does the software flag photos that you need to check by eye?
During any one night’s session, maybe 100 or so [get flagged]. But because they’re just little preview windows I can flip through them very quickly. You also have real objects, like asteroids and other comets, so I have to eliminate those. There are some good Web sites as well where you can put in a position and you can see any known objects in that area.
So your software finds 100 possible objects every night but you had to go a year or two before one turned out to be real?
That’s right. It’s certainly very obsessive when you put it like that.
For the last two comets I went though about 70,000 images to find each comet. There’s a lot of time, even now, between comets. For me it’s the challenge of working on the telescope, working on the software to get it more efficient—that’s the satisfaction I get out of it. I think the actual discovery is probably not as exciting now as it was for the first one.
Tell me about this latest discovery. How long was it before you knew it was a new comet for sure?
It was probably about a day before I knew. I had made contact with a couple people and said, “I think I found something; I’m not 100 percent sure.” I found it in the morning, and I had confirmation from a Facebook friend in the evening when I was on the way home on the train.
At that point I knew we had a comet. But you need to get enough observations of the comet and its positions in the sky to calculate an orbital trajectory. Generally you need about two to three days of those observations. Once you have found the orbit you can compare it to any historic objects that may have been here in the past and are returning. Then you can confirm it’s a new comet.
So your new comet has not been to the inner solar system before?
Apparently 13,000 years ago it did [according to orbital calculations]—but not in recent human history. It will return in 8,000 years. It’s kind of cool to think about that.
How did you get into amateur astronomy?
I grew up in a place called Cumnock, in central New South Wales. Because it was so far away from any major cities we had very dark skies, and I think it was there where I became interested. My father got woken up one morning for work and it was pitch black, like it normally is when there’s no moon, and he was walking outside and saw this giant feather in the sky—that’s how he described it. Then it took a few moments and he thought, “That’s a comet.”
That turned out to be a Kreutz sungrazing comet, Comet C/1965 S1 (Ikeya-Seki), so it’s fitting that I found a comet in 2011 that was [also a Kreutz sungrazer]. That’s how it all really began.
And when did you become a more serious comet hunter?
Around 2004 I kind of fell into that. I was following a lot of the known comets as well as looking at other objects. But one thing I noticed is that being in the Southern Hemisphere, a lot of comets were not being found. All of the people looking for comets appeared to be in the Northern Hemisphere. I thought, I’ve probably got an opportunity here to go and find some comets.
I don’t think I’ve really ever had that drive to get up at all hours of the night and stare through an eyepiece—to me that wasn’t fun. But when digital cameras and decent quality CCD cameras started to appear I thought I could automate a system and then I could live a normal life.
Between your full-time job and your astronomical activities, do you get enough sleep?
No, not really. Well, believe it or not, I usually get eight hours of sleep but sometimes it’s interrupted.
What advice do you have for people who would like to get into comet hunting?
Don’t be too serious about it. Often people go out and buy all the best equipment and then realize it’s not for them, or they burn out and get overwhelmed by it. My advice is that people start fairly simple and not spend lots of money. Just go and buy some binoculars or a small Dobsonian telescope and then develop your own interest that way. Some people go and buy too large a telescope. There’s not much point if you can’t move it or get it into your car. There are also people who say you’re not an amateur astronomer unless you’re doing serious observations and I think that’s wrong as well. You’re doing this for enjoyment. The serious stuff can come later.