The One Degree Imager (ODI) was deployed during the summer of 2012 at the WIYN 3.5m telescope, located on Kitt Peak near Tucson, AZ (USA). ODI is an optical imager designed to deliver atmosphere-limited image quality (≤ 0.4” FWHM) over a one degree field of view, and uses Orthogonal Transfer Array (OTA) detectors to also allow for on-chip tip/tilt image motion compensation. At this time, the focal plane is partially populated (”pODI”) with 13 out of 64 OTA detectors, providing a central scientifically usable field of view of about 24′ x 24′; four of the thirteen detectors are installed at outlying positions to probe image quality at all field angles. The image quality has been verified to be indeed better than 0.4′′ FWHM over the full field when atmospheric conditions allow. Based on over one year of operations, we summarize pODIs performance and lessons learned. As pODI has proven the viability of the ODI instrument, the WIYN consortium is engaging in an upgrade project to add 12 more detectors to the focal plane enlarging the scientifically usable field of view to about 40′ x 40′. A design change in the new detectors has successfully addressed a low light level charge transfer inefficiency.
User interfaces (UIs) are a necessity for almost any data acquisition system. The development team for the WIYN One
Degree Imager (ODI) chose to develop a user interface that allows access to most of the instrument control for both
scientists and engineers through the World Wide Web, because of the web's ease of use and accessibility around the
world. Having a web based UI allows ODI to grow from a visitor-mode instrument to a queue-managed instrument and
also facilitate remote servicing and troubleshooting. The challenges of developing such a system involve the difficulties
of browser inter-operability, speed, presentation, and the choices involved with integrating browser and server
technologies. To this end, the team has chosen a combination of Java, JBOSS, AJAX technologies, XML data
descriptions, Oracle XML databases, and an emerging technology called the Google Web Toolkit (GWT) that compiles
code in Java, GWT's native support for AJAX, the use of XML to describe the user interface, the ability to profile code
speed and discover bottlenecks, the ability to efficiently communicate with application servers such as JBOSS, and the
ability to optimize and test code for multiple browsers. We discuss the inter-operation of all of these technologies to
create fast, flexible, and robust user interfaces that are scalable, manageable, separable, and as much as possible allow
maintenance of all code in Java.
The WIYN One Degree Imager (ODI) exposure system must drive multiple complex subsystems requiring large
amounts of configuration information that may change substantially between exposures. The mosaic OTA focal plane
provides up to 64 streams of image data during readout or 512 ROI video streams for guidance or real time photometry.
The work flows and instrument operation sequences are numerous, and are evolving to adapt to the new capabilities the
mosaic OTA (Orthogonal Transfer Array) camera presents. By making scripting data driven, the ODI exposure system
provides a very flexible, but structured and powerful paradigm for instrumentation process control and operation.
The One Degree Imager will be the future flagship instrument at the WIYN 3.5m observatory, once commissioned in
2011. With a 1 Gigapixel focal plane of Orthogonal Transfer Array CCD devices, ODI will be the most advanced optical
imager with open community access in the Northern Hemisphere. In this talk we will summarize the progress since the
last presentation of ODI at the SPIE 2008 meeting, focusing on optics procurement, instrument assembly and testing, and
As camera focal planes become larger, with higher resolutions and increasingly higher data throughputs, the more they
resemble the enterprise data systems found in commercial data centers. The WIYN One Degree Imager (ODI) is such a
system. ODI is a mosaic imager with 64 independent CCD detectors with a total resolution of approximately a gigapixel,
covering 1 square degree of the sky at the WIYN 3.5 m telescope at Kitt Peak. The ODI camera will bring improved
seeing, widefield imaging, new modes of operation and automated integration with the NOAO Science Archive. It will
also become the workhorse instrument of the observatory, with high availability and reliability. The new flexibility of
the camera will allow (and require) constant refinement of imaging techniques, and calibration and maintenance
Large scale, parallel data processing, management and control will be a constant in the operation of the instrument. We
are developing an enterprise level data system using typical Java J2EE constructs. With the advent of relatively
inexpensive clustered hardware, scaling of image operations and management to the large volumes of data in ODI
should be simplified. We describe an architecture in construction for ODI's 2010 deployment.
The WIYN consortium is building the One Degree Imager (ODI) to be mounted to a Nasmyth port of the WIYN 3.5m
telescope, located at Kitt Peak, Arizona (USA). ODI will utilize both the excellent image quality and the one-degree
field of view that the telescope delivers. To accommodate the large field of view (~0.39m diameter unvignetted field
with 0.54m across the diagonal of the one-degree-square, partially vignetted field), 0.6m-class optics are required. The
ODI design consists of a two element corrector: one serves as a vacuum barrier to the cryostat, the other is an asphere;
two independently rotating bonded prism pairs for atmospheric dispersion compensation (ADC); nine independently
deployable filters via a simple pivoting motion; and a 971 mega-pixel focal plane consisting of 64 orthogonal transfer
array (OTA) devices.
This paper is an overview of the mechanical design of ODI and describes the optical element mounting and alignment
strategy, the ADC & filter mechanisms, plus the focal plane. Additionally, the project status will be discussed.
In accompanying papers Jacoby<sup>1</sup> describes ODI's optical design, Yeatts<sup>2</sup> describes the software and control system
design, and Harbeck<sup>3</sup> gives a general update on the project.
The WIYN Consortium is building the One Degree Imager (ODI) for its 3.5m telescope, located at Kitt Peak, Arizona
(USA). ODI will utilize both the excellent image quality and the one degree field of view of the WIYN telescope. Image
quality will be actively improved by localised tip/tilt image motion stabilisation using a novel concept of Orthogonal
Transfer Array (OTA) CCDs, which are a new detector type jointly developed with the PanSTARRS project. Its anticipated
median image quality of ≤ 0.55" in the R band will make ODI a unique and competitive instrument in the landscape of the
next generation of large field imagers.
A conceptual design of ODI was presented earlier at SPIE.<sup>1</sup> In the meantime, this concept matured, the ODI project has
been fully funded, and it has entered the construction phase. A prototype camera (QUOTA) with a field of view of 16'x16'
has already seen first star light in fall 2006. In this paper we report on the evolution of ODI's definition, the design of its
components, the status of the OTA detector development, and the path towards first light in early 2010. In accompanying
papers we detail the design of the ODI's optical corrector, the mechanical structures, and the software & instrument system