----------------------------------------------------------------------------- Yohkoh Legacy Level 1 SXT File Name Convention J. R. Lemen, 04 Aug 2005 revised, 11 Feb 2008 (by Aki Takeda) ----------------------------------------------------------------------------- This document defines the Yohkoh Legacy file naming convention for Level 1 SXT data. Level 0 data files are produced by the Yohkoh reformatter, and naming convention of those files remains the same as they were defined during the operational phase and as assigned by the Yohkoh reformatter. Additional information about the Level 0 data files is available elsewhere. The Level 1 file name includes various information about the data that are contained within the file. In particular, it identifies the file as containing Yohkoh/SXT images, whether from full-frame or partial frame operation, the start time of the image, the key instrument parameters (normal or dark, filter, resolution), and the Level 1 processing options that were applied. This information can also be determined by reading the FITs header, but the intent of the file name specification is to enable users and services to be able to quickly identify key aspects of the data without requiring the file to be opened and read. A. Definition of Level 1 SXT data files Yohkoh Legacy Level 1 SXT files contain by definition SXT image data. There are other data files that are necessary to fully analyze or understand the SXT images that are not addressed here. These other files make up the associated mission and instrument databases and various observing and event catalogs. The Level 1 SXT files have four global characteristics: 1. Data are uncompressed 2. One image per file 3. Data are in FITS format 4. The files will have 28-letter names of the form: SXTF_yyyymmdd_hhmmss_YYY.fts (full frame) or SXTP_yyyymmdd_hhmmss_YYY.fts (partial frame) B. Description of the naming convention The file names have four parts: a prefix, a time stamp, a 3-letter instrument mode description (YYY), and a suffix (.fts). These are described below. B.1 Prefix The file prefix is four letters and occupies positions 0-3. The two possible combinations are as follows: SXTF = Full-frame data (sfr) SXTP = Partial-frame data (spr) B.2 Time The time is 16 character sequence in the file name and occupies positions 4-19. The format is as follows: _yyyymmdd_hhmmss Note that the time given is the nominal start exposure time. In the case of composites, it is the longest exposure. In case of PFI ORs (observing regions, i.e., assembled PFIs), it is the start exposure time of the earliest exposure. B.3 Instrument Mode (_YYY) Key instrument mode parameters are defined in a three letter hexadecimal sequence preceded by an "underscore", _YYY. The instrument mode occupies positions 20-23 in the file name and is defined as follows: Bits Item 0-3 Front Filter wheel (non-high cadence mode) 3,2,1,0 = [0,0,0,1] = Open [0,0,1,0] = NaBan [0,0,1,1] = Quart [0,1,0,0] = Diffu [0,1,0,1] = WdBan [0,1,1,0] = NuDen 3 If set, high cadence mode (rarely used) 4-7 Rear Filter wheel 7,6,5,4 = [0,0,0,1] = Open [0,0,1,0] = Al.1 [0,0,1,1] = AlMg [0,1,0,0] = Be119 [0,1,0,1] = Al12 [0,1,1,0] = Mg3 8-9 9,8 = Resolution ([0,0]=full, [0,1]=half, [1,0]=quarter) 10 If set, dark exposure (no shutter) 11 If set, calibration mode (light transfer) or BLS turned on Note: For normal exposures, bits 10 and 11 are not set. Examples: _YYY = 121 Open/Al.1 HR Norm _YYY = 231 Open/AlMg QR Norm _YYY = 431 Open/AlMg FR Dark B.4 Suffix field Every file ends with same four character suffix which occupies positions 24-27 in the file name: .fts ----------------------------------------------------------------------