1. SPACE TELESCOPE SCIENCE INSTITUTE Operated for NASA by AURA COS Pipeline PDR File Structure Overview Charles D. (Tony) Keyes 7 December 2000

2. COS PIPELINE PDR Tony Keyes December 7, 2000COS File Structure Overview Space Telescope Science Institute 2 of 13 COS Data Format  2-d data: FITS files containing imsets consisting of science and data quality images (unlike STIS, no error array)  1-d data and TIME-TAG lists: FITS tables containing fluxes, wavelengths, errors, quality, positions, and other related quantities  May explore compression for reduced dataset volume  Data from each FUV detector segment stored as separate imset series within a single file – All associated data (e.g., wavecals, FP-SPLIT components, REPEATOBS components, STIMs) use separate files (unlike STIS)

3. COS PIPELINE PDR Tony Keyes December 7, 2000COS File Structure Overview Space Telescope Science Institute 3 of 13 Data File Naming Conventions   Product Suffix Type Contents   ---------------------------------------------------------------   Uncalibrated _raw image Raw counts image   _rtg table Raw TIME-TAG event list   _asn table Association file   _trl table Trailer file (input)   _lrc image Local rate check image [TBD]   _lsp text LRC support file (header) [TBD]   _jit table   _jif image   _pha table Pulse-height (FUV ACCUM only)   _rs1 image Stim-pulse 1 (FUV ACCUM only)   _rs2 image Stim-pulse 2 (FUV ACCUM only)  

4. COS PIPELINE PDR Tony Keyes December 7, 2000COS File Structure Overview Space Telescope Science Institute 4 of 13 Data File Naming Conventions (continued)   Product Suffix Type Contents  ---------------------------------------------------------------   Calibrated _ctg table Calibrated TIME-TAG event list   _flt image Flat-fielded, corrected counts   _fls image Summed flat-fielded corrected-counts   _x1d table 1-D extracted spectra   _x1s table Summed (combined) 1-D extracted spectra)   _cs1 image Corrected stim-pulse 1 (FUV ACCUM only)   _cs2 image Corrected stim-pulse 2 (FUV ACCUM only)   _trl table Trailer file (output)   _spt image Support file (header)  ---------------------------------------------------------------  Wavecal exposures produce same calibrated files as science, except there may be no flux calibration applied to the _x1* files (TBD). Dark and flat exposures produce no _x1* files. Acquisition exposures produce no calibrated products.

5. COS PIPELINE PDR Tony Keyes December 7, 2000COS File Structure Overview Space Telescope Science Institute 5 of 13 COS Observational Quantity Definitions   x = raw detector x-position (I*2)   y = raw detector y-position (I*2)   t = time of photon detection (R*4)   ph = pulse-height (I*1)   xcorr = corrected detector x-position (R*4)   ycorr = corrected detector y-position (R*4)   EPS = photon list sensitivity-parameter (R*4)   obsC = observed counts (R*4)   C = corrected counts (R*4)   q = data quality (I*1)   lambda = wavelength (R*4)   F = calibrated flux (F-lambda) (R*4)   G = gross extracted counts (R*4)   N = net extracted counts (R*4)   B = background extracted counts (R*4)   S = sensitivity function (R*4)

6. COS PIPELINE PDR Tony Keyes December 7, 2000COS File Structure Overview Space Telescope Science Institute 6 of 13 File Contents: Observational Quantities   _rtg: contains x,y,t,ph (no ph for NUV) – – FUV: 9 bytes/event; NUV: 8 bytes/event   _ctg: contains xcorr,ycorr,t,ph,EPS,q,lambda (no ph for NUV) – – FUV: 22 bytes/event; NUV: 21 bytes/event   _raw: contains obsC – – FUV: 32 Mbyte/file; NUV: 4 Mbyte/file   _flt: contains C,q (in each imset) – – TIME-TAG: FUV: 160 Mbyte/file; NUV: 5 Mbyte/file – – ACCUM: FUV: 40 Mbyte/file; NUV: 5 Mbyte/file   _fls: same as _flt   “_obs”: contains obsC (in each imset) [size same as _raw]   _x1d: contains F,lambda,G,N,B,S,q (in each imset) – – FUV: ~1 Mbyte/file; NUV: ~0.08 Mbyte/file   _x1s: same as _x1d   _rs1: contains obsC (same for _rs2)   _cs1: contains C (same for _cs2)

7. COS PIPELINE PDR Tony Keyes December 7, 2000COS File Structure Overview Space Telescope Science Institute 7 of 13

8. COS PIPELINE PDR Tony Keyes December 7, 2000COS File Structure Overview Space Telescope Science Institute 8 of 13 Time-Tag Data File Structure

9. COS PIPELINE PDR Tony Keyes December 7, 2000COS File Structure Overview Space Telescope Science Institute 9 of 13 ACCUM / FPsplit = no Data File Structure

10. COS PIPELINE PDR Tony Keyes December 7, 2000COS File Structure Overview Space Telescope Science Institute 10 of 13 ACCUM / FPsplit = yes or REPEATOBS=N Data File Structure

11. COS PIPELINE PDR Tony Keyes December 7, 2000COS File Structure Overview Space Telescope Science Institute 11 of 13 File Naming   TIME-TAG “FP-SPLIT=NO" exposure:     Wavecal exposure science exposure   (401s) (402s)     association file: 4010_asn     wavecal exposure files: 401s_rtg   401s_ctg   401s_flt   401s_x1d     science exposure files:402s_rtg   402s_ctg   402s_flt     association science product file:4010_x1d

12. COS PIPELINE PDR Tony Keyes December 7, 2000COS File Structure Overview Space Telescope Science Institute 12 of 13 File Naming   TIME-TAG FP-SPLIT=YES exposure:     Wavecal exposure science exposure   (401s) (402s)   science exposure science exposure   (403s) (404s)   science exposure   (405s)     association file: 4010_asn     wavecal exposure files: 401s_rtg 401s_ctg 401s_flt 401s_x1d     science exposure 1 files: 402s_rtg 402s_ctg 402s_flt 402s_x1d   science exposure 2 files: 403s_rtg 403s_ctg 403s_flt 403s_x1d   science exposure 3 files: 404s_rtg 404s_ctg 404s_flt 404s_x1d   science exposure 4 files: 405s_rtg 405s_ctg 405s_flt 405s_x1d   association science product file: 4010_x1d

13. COS PIPELINE PDR Tony Keyes December 7, 2000COS File Structure Overview Space Telescope Science Institute 13 of 13 COS Typical File Sizes