Ever Improving Optics

Advancing telescopes' adaptive optics systems in part by building strong teams.

Anand Sivaramakrishnan
Anand Sivaramakrishnan

On its face, chaos theory sounds more akin to pandemonium than to order. But those who study it are rooted in finding underlying patterns and connections in complex systems. Dr. Anand Sivaramakrishnan devoted his PhD to chaos theory and it led him to the field of adaptive optics. He's spent decades designing systems that sense and correct errors in a telescope's optics. Although there are numerous steps to each project—and many challenges in each—he finds collaboratively problem solving is the most rewarding. Here, he shares how he stays open to new ideas, focused, and refreshed in a challenging field.

How did you find your way to the field of adaptive optics?

As a kid, I started taking photographs with the Kodak Brownie camera in England. I've always been interested in making really good, sharp images. I think that eventually drove me to select this specialization after decades of immersion in mathematics and physics. After I earned my PhD, I accepted a job coding instruments at the Carnegie Observatories in Pasadena, California. Instruments, of course, have optics, and I got sucked into that. Then my theory and optics expertise combined to make me suitable for adaptive optics. I went to Caltech to work on Palomar Observatory's major adaptive optics system on the 200-inch telescope. That got me into imaging and looking for planets around other stars, along with the theory for that instrumentation. My day job was getting the instrument going. At night, I'd work on the theory.

Why did you join STScI for the first time in 1997? How did that lead into your work on Gemini?

I came to the East Coast to be closer to my family. When work on the James Webb Space Telescope started ramping up, they needed someone with background in advanced optics. I ran the institute's wavefront sensing and control system development for Webb, which senses and corrects errors in the telescope's optics. At the same time, I worked on an adaptive optics coronagraphic camera for a U.S. Airforce satellite-tracking telescope with Rebecca Oppenheimer, who was then a postdoc.

We would talk to each other on the phone, going through a whole systems analysis in half an hour. I'd be typing and running code and she'd be saying, "If we go slower, we get better signal." or "How bright can the star be?" It was really exhilarating to be answering questions nobody had asked before and having someone really smart challenging me. Around that time, I developed the idea for the Gemini Planet Imager coronagraph with Russ Makidon. We spent a few years writing a giant proposal for it with Rebecca and my postdoc Rémi Soummer [who now leads STScI's Russell B. Makidon Optics Laboratory]. When we got the grant, I left STScI for the American Museum of Natural History to develop and test Gemini's coronagraph.

When we started making the coronagraph on the testbed, we were very lucky that Laurent Pueyo joined us. The hardware was more complicated and we became more methodical. After we developed the coronagraph's masks, we sent them to Santa Cruz. They were integrated with the adaptive optics, shipped, and finally commissioned. For me, the thrill was figuring out what we can do that hadn't been done before, showing it's very likely to work, and then seeing it work.

What did you tackle after you rejoined the institute in 2010?

I had always been concerned that Webb had only one camera, the Near-Infrared Camera (NIRCam), to sense and correct errors in the telescope's optics. With a few colleagues, I developed a redundant approach to use another instrument I worked on—Webb's Near-Infrared Imager and Slitless Spectrograph (NIRISS)—to perform the same functions. Instrumentalists always have to consider worst-case scenarios. You designed an instrument and it should work, but does it? I am motivated by a very strong sense of duty.

I also contributed to the Nancy Grace Roman Space Telescope, which was then known as the Wide-Field Infrared Survey Telescope or WFIRST. I served on the first two major reviews of the mission. Through all my years of "dirt biking" through new coronagraphic territory, I wanted to help ensure that Roman's coronagraph will support the next big exoplanet science mission.

In 2021, I captured the attention of world-class scientists Joel Sánchez, Benjamin Pope, and Jens Kammerer, who use interferometers, instruments that split and recombine a target's light to provide better detail than a straightforward image can. They helped me extend the science possibilities for the new mask my team put into Webb's NIRISS instrument.

Why are teamwork and collaboration central to your pursuit of science?

I really love exploring new frontiers with small teams. We're like a group of friends getting up to mischief. When I was working in Pasadena with Rebecca, we discussed things all the time. I shared what I knew and she picked it up right away and took it further. We kept collaborating like that. Like many other people I've worked with, we spark ideas in each other.

When Rémi joined me as a postdoc, he had phenomenal expertise and a very formal, elegant approach to math. I had a seat-of-the-pants approach to math. It was a great match. We were very productive. I could see that all the coronagraphs I was involved in would really benefit from having Rémi central in developing the ideas. I helped put him front and center as the project developed, knowing he would help us make progress more quickly.

What did you learn from one of your first mentors?

When I started at Carnegie, a senior astronomer, Ray Weymann, liked to know what everyone did, especially newcomers. I told him I'm interested in adaptive optics. Several months later, we started talking in earnest. He didn't know much about adaptive optics, so he'd ask me really basic questions. He asked questions like this all the time. He taught me to use my ignorance. Say, "I don't know what that is." Ask, "What is that?" and if no one can answer, rip it apart and understand its insides. He taught me that ignorance is the best tool of a scientist. I often share this with graduate students and watch their faces relax. Never feel bad about not knowing the answer. Instead, follow your questions so you can always keep learning.

Article updated March 2022.