Far Ultraviolet Wide Field Imaging And Photometry: Spartan-202 Mark II Far Ultraviolet Camera

The Spartan-202 space shuttle mission will include, as its primary scientific instrument, the Naval Research Laboratory's Mark II Far Ultraviolet Camera. The primary scientific objectives of this mission are imaging and photometry, over large areas of the sky, of hot stars, diffuse nebulae, and nearby external galaxies. It is intended to produce a more sensitive and higher resolution far-UV sky survey than previous, similar investigations. The observations provide information on the temperatures and total luminosities of hot stars, and on the far-UV extinction and reflection by interstellar dust, which cannot be obtaihed with ground-based instrumentation or as efficiehtly with other space-based instruments. The measurements complement and support those to be made with the Hubble Space Telescope and the Astro Ultraviolet Imaging Telescope, which have higher angular resolutions and point-source sensitivities but smaller fields of view and lower diffuse-source sensitivities than the Mark II Far UV Camera. The instrument is an electrographic Schmidt camera, similar to but larger (and having higher resolution and point-source sensitivity) than similar cameras we have used in numerous other space flight experiments. The principles, design, and sounding rocket flight history of the Mark II camera are discussed, as well as modifications required to adapt the instrument for the Spartan flight. Target selection criteria, tentative observing plans, and growth potential in the Space Station era are also discussed. Data reduction and analysis plans are described.