The observatory is a collaboration between oceanographers and engineers at the University of Washington's Applied Physics Laboratory and the Puget Sound Skills Center's Environmental and Marine Science program. The Marine Science program has a wonderful shoreside facility located at the north end of Seahurst Park in Burien, Washington. To support the salmon hatchery located at the facility there are two saltwater intake pipes that run 850 feet from the building out to 25 feet of water. Those pipes provide an ideal means to run power and fiber optic ethernet cables for underwater instruments, providing a permanent, real-time, high bandwidth presence on the bottom of Puget Sound.

The observatory was installed through a combination of volunteer efforts and a science and engineering development project at APL-UW funded by the National Science Foundation. That project is working to install a cabled-to-shore profiling mooring at the MARS observatory in Monterey Bay, California. The installation at Seahurst provides a plug compatible observatory interface for testing that system in diver accessible depths right in our own backyard.

Many thanks are due to the outstanding group of volunteers who have made this installation possible through their diving, rowing, cable pulling, and general engineering prowess: Eric Boget, Paul Fischbach, Jason Gobat, Bruce Howe, Cyrus Howe, Tim McGinnis, Geoff Shilling, Chris Siani, Troy Swanson, Keith Van Thiel, and Joe Weiss. Special thanks also to Highline School District facilities and IT personnel for their assistance with the necessary wiring and connectivity changes and Burien Parks for their continued support of the PSSC Environmental and Marine Science facility at Seahurst.

Technical details
The observatory provides 400V DC power and fiber optic ethernet from the shore through separate copper and fiber cables to the Seahurst Node. The node is essentially a junction box that distributes power and converts to electrical ethernet. The node contains a 5-port ethernet switch, one port of which takes a fiber optic multimode pair from the shore cable, and a 400V-48V DC/DC converter. Electrical ethernet, 400V (connected directly to shore power) and 48V DC power (from the 400-48 converter) are made available on each of three connectors. Two of these are intended for "guest" systems, the first of which will be the profiling mooring described above.

The third port is dedicated for a connection to the permanent Seahurst SIIM (Sensor Instrument Interface Module). Most oceanographic instruments do not use ethernet for communications or need 400V (or even 48V) DC power. The SIIM provides a more suitable interface for common instruments. It contains a 48V-12V DC/DC converter, 8-port ethernet switch, ethernet enabled frame grabber (for the camera), and five serial channels for oceanographic instruments. Each of the serial channels is enabled by a DigiConnect ethernet to serial converter. The current sensor suite consists of a borrowed Falmouth Scientific, Inc. NXIC conductivity, temperature and pressure recorder, and an analog underwater camera with integral LED lighting. Secci disks are placed 3 meters and 5 meters from the camera. We are actively seeking sources or funding for additional instruments to add to the permanent installation.

A preliminary block diagram with additional details about the installed hardware is available here.

Available data
Data from the CTD is collected every 1.5 seconds. Time-lapse video frames are taken every 10 seconds. Daily time-lapse videos are archived. Full-rate video is captured and archived when motion is detected. For presentation on the front page of the web site a snapshot is taken once per minute and twenty seconds of full-rate (10 fps) video is taken every five minutes. These snapshot pictures and videos are not archived (every new snapshot overwrites the previous). The snapshot pictures are only displayed as a fallback when a suitable version of Flashplayer is not available.

Every five minutes, all recent CTD data and the most recent videos and shapshot images are pushed from the shoreside server to a web server located at APL-UW.

Full-rate snapshot and motion capture video are converted to Flash video format (FLV) for presentation on the web. We use FlowPlayer to embed the videos in the pages. In our testing embedding Flash appeared to be the most cross-platform compatible, reasonable bandwidth solution. For the timelapse videos we continue to use MPEG with the Quicktime plugin because it has the best support for single frame forward/back that we have seen in commonly available plugin players.

Full-rate, real-time video is available for viewing by students on the internal Marine Technology LAN. Real-time video can be streamed off site for special events and presentations.