Near-bottom ROV photomosaics (PNG format) from the Octopus Garden hydrothermal spring site

High-resolution photographs were collected with dual Prosilica GX1920 2.4 Mpixel color cameras that are part of the MBARI Low Altitude Survey System mounted for two dives in 2021 to the ROV Doc Ricketts, which was flown at 3 m altitude at speeds <= 1.0 m/s to produce photomosaics presented here at 3 mm resolution. The field of view of each image is 80 degrees and raw image pixel resolution is 2 mm. The photomosaics were generated using the MB-System program mbphotomosaic, which projects each pixel from source images onto the 5-cm resolution topographic model from the multibeam data, and are presented as 10 tiles named like W1-W5 and E1-E5. File format is PNG and the associated world file is included for use with GIS. Projection is the WGS-1984 geographic coordinate system. Position and attitude data are provided by a Kearfott SeaDevil Inertial Navigation System (INS) integrated with a 1200 kHz Teledyne RD Instruments Doppler velocity log (DVL) and a Paroscientific pressure sensor. Illumination was with four xenon strobes mounted on swing arms. The sensor package is mounted into an articulating frame within an ROV toolsled that rotates from pointing the sensors vertically down to horizontally forward, allowing surveys of flat to vertical seafloor. The articulation is automated by closing a control loop around the difference between the forward and backward beams of the DVL. Funding was provided by a grant from the David and Lucile Packard Foundation to MBARI.