<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">To the FITS community:<div><br></div><div>NOAO and the Dark Energy Consortium have submitted an entry, called the <a href="http://fits.gsfc.nasa.gov/registry/tpvwcs.html">TPV World Coordinate System</a>, to the <a href="http://fits.gsfc.nasa.gov/fits_registry.html">Registry of FITS Convention</a>s which will be used by the premier new instrument, the Dark Energy Camera, currently being commissioned at NOAO (Blanco 4m at CTIO). It is also being proposed for use by another major large format camera, the WIYN One-Degree Imager. This registry entry provides documentation for both future consumers of data from these instruments as well as developers supporting FITS WCS. It is our hope to garner this support in the major software tools and libraries that work with astronomical FITS images. This convention has already had buy-in (and implementation) from IRAF, SAO DS9, SAO WCSTOOLS, Astromatics (e.g. Scamp).</div><div><div><br></div><div>The convention is straightforward and has a pedigree as a suggestion from Calabretta and Greisen. This registration differs from their suggestion only in specifically identifying this WCS by the CTYPE of TPV (tangent plane with PV polynomial distortion coefficients).</div><div><br></div><div>A second convention added to the registry by NOAO/IRAF is a WCS labeled as <a href="http://fits.gsfc.nasa.gov/registry/zpxwcs.html">ZPX</a> (zenithal WCS with distortion terms). A large body of NOAO Mosaic Camera data has been archived using this WCS. The registration was submitted to rectify an omission of following the FITS registry process.</div><div><br></div><div>Discussion of these conventions is appropriate for the FITS WCS mailing list (<a href="mailto:fitswcs@nrao.edu">fitswcs@nrao.edu</a>). Please reply only to this list rather than all.</div><div><br></div><div>Dr. Francisco Valdes</div><div>NOAO</div></div></body></html>