Bigger, sharper images to be refined, processed, stored at IU

BLOOMINGTON, Ind. -- Recording light from millions of light years away and then sending it to the Indiana University Data Center at the corner of 10th Street and the State Road 45/46 Bypass, a new camera at Kitt Peak National Observatory in Arizona's Sonoran desert will image an area of sky five times that of the full moon, yet still focus at the equivalent of seeing a baseball from 30 miles away.

The new One Degree Imager camera at Kitt Peak's WIYN 3.5-meter telescope will offer IU astronomers -- like IU College of Arts and Sciences' Astronomy Department assistant professor Katherine Rhode, who studies distant globular star clusters -- superb image quality across the camera's entire field of view. The camera provides image sharpness and resolution for objects as small as 0.3 arc seconds -- one arc second is 1/3600 of a degree -- and the field of view will eventually cover a full one degree across.

The WIYN telescope has a new camera, the One Degree Imager (pictured), that offers a wide field of view and exceptional image resolution. The two-gigabyte images will be refined and processed at IU's Pervasive Technology Institute. Indiana University

"This new camera represents a major step forward for IU Astronomy, the WIYN Observatory partners and the astronomical community as it will enable IU researchers and students to study the universe in big chunks instead of tiny pieces," Rhode said. "We can image entire star clusters, galaxies and groups of galaxies all at once, while still seeing the detailed features of each object. We can study a globular cluster made up of tens of thousands of stars, while at the same time imaging the individual stars that are packed into the cluster's central regions. We can study a giant spiral galaxy while simultaneously resolving the individual knots of star formation embedded within its spiral arms. And we can image dozens of galaxies in a galaxy cluster, measuring the light coming from each individual galaxy as well as studying how the galaxies and their stars and gas interact with each other as they orbit a common center of gravity."

Those huge images -- each will be two gigabytes in size -- will also generate between two and four terabytes of data each week, and that's where IU's Pervasive Technology Institute is contributing to the massive effort needed to process the data from those different types of images.

PTI is developing the Web-based science gateway, called the ODI Pipeline, Portal and Archive, to help researchers pool resources and analyze, manipulate and store data from the camera. Data will be moved from Kitt Peak to IU, initially to the Data Capacitor system hosted in the IU Data Center, so that initial images can be refined and processed. Those refinements will take place on XSEDE -- the eXtreme Science and Engineering Discovery Environment -- a national grid of supercomputers that IU helps operate. Processed, science-grade images are then stored in the highly secure IU Scholarly Data Archives.

"The ODI-PPA gateway allows astronomers to work with large data sets without having to download it to a personal computer, and to get their visual analysis as well as data processing done on a massive distributed grid and cloud-based computer resources via our portal," said Arvind Gopu, the University Information Technology Services Research Technologies and PTI project manager in charge of the gateway. "With our gateway, astronomers from all over, not just IU, can search, download and process data in the cloud, allowing the ODI instrument to truly achieve its full potential. This is a perfect example of PTI and IU research scientists collaborating to develop tools that benefit research at IU and worldwide."

Once data are moved to and archived at the IU Data Center, astronomers will no longer need to transfer all the intermediate stages of their data to their home computers. Instead, they'll be able to work in a cloud configuration, downloading only their final results.

The WIYN telescope is operated by IU, Yale University, the University of Wisconsin and the National Optical Astronomy Observatory, and astronomers from all over the world apply for time to use what is considered one of the best telescopes for optical imaging in use today. The telescope can be controlled by a computer in Swain Hall West on the Bloomington campus, and students and faculty can video conference with Kitt Peak and manipulate the WIYN telescope's instruments as if there.

"One important role our graduate students are playing right now is to help with commissioning the new camera, since once a new instrument is installed, it needs to be adjusted to obtain the best image quality, thoroughly tested to make sure everything works as expected, and then characterized to quantify and document how it responds to incoming light and how it can be used to obtain precision flux measurements in various wavebands," Rhode said. "Working on the commissioning of a world-class imager like this is a great opportunity for our students, since -- as part of their graduate education -- they are learning about how to develop and use astronomical cameras and other instruments."

Images from the new 2,800-pound camera will be stabilized to compensate for motion due to atmospheric turbulence, telescope shake and tracking errors by using a technology called Orthogonal Transfer Array charge-coupled device sensing. The initial configuration of the camera includes 13 charge-coupled device detector arrays; when ODI is fully deployed, it will include 64 charge-coupled device detector arrays, with a total of over a billion pixels.

Rhode said having a camera with a wide field of view allows for imaging of objects like a Milky Way open star cluster, or a giant spiral galaxy with its own population of globular star clusters, in a single pointing. That means more efficient observing and an easier way to accurately compare multiple objects and characterize fluxes of those objects.

"Having a wide field will allow us to study these objects in their entirety to measure accurate global properties and to study how their properties vary spatially across the field," she said.