The SAGE Photometric Sky Survey: Technical Description

To investigate in more details of Stellar Abundance and Galactic Evolution (SAGE) and in a huge sample, we are performing a northern sky photometric survey named SAGES with the SAGE photometric system, which consists of 8 filters: Str"omgren-$u$, SAGE-$v$, SDSS $g$, $r$, $i$, DDO-$51$, $H{\alpha }_{wide}$, and $H{\alpha }_{narrow}$, including three Sloan broadband filters, three intermediate-band filters and two narrow-band filters, and one newly-designed narrow-band filter. SAGES covers $\sim$12,000 square degrees of the northern sky with $\delta >-5^{\circ }$, excluding the Galactic disk ($\mathrm{\mid }b\mathrm{\mid }<{10}^{\circ }$) and the sky area of 12 hr $<$ R.A. $<$ 18,hr. The photometric detection limit depth at signal-to-noise ratio $5\sigma$ can be as deep as $V\sim$20,mag. The SAGES will produce a depth-uniformed photometric catalogue for $\sim$500 million stars with atmospheric parameters including effective temperature $T_{\mathrm{e}\mathrm{f}\mathrm{f}}$, surface gravity log,g, and metallicity [Fe/H], as well as interstellar extinction to each individual target. In this work, we will briefly introduce the SAGE photometric system, the SAGE survey, and a preliminary test field of the open cluster NGC,6791 and around.