... In this Appendix we will describe the items that can be present in an image dataset. Miriad utilities such as prthd , imlist , itemize , puthd , copyhd and delhd may be used to browse or modify these `header variables'. ... Table: Item names in Miriad image datasets . ... real . ... Beam major and minor axis FWHM. bpa . ... character . The units of the pixels. btype . ... cdelt1,cdelt2,... double . See ctype . ... The pixel coordinate of the reference pixel. crval1,crval2,... double . ...

metrologia The leap second: its history and possible future R. A. Nelson, D. D. McCarthy , S. Malys, J. Levine, B. Guinot, H. F. Fliegel , R. L. Beard and T. R. Bartholome w Abstract. This paper reviews the theoretica l motivatio n for the leap second in the context of the historica l evolutio n of time measurement . Th e periodic insertio n of a leap second step into th e scale of Coordinate d Universal Time (UTC) necessitates frequent changes in comple x timekeepin g systems an d is currentl y th e