Incorporating Observations into the

RHESSI Synoptic Data Archive

Use FITS format for individual files. FITS format ensures that the data will portable to different platforms and readable in a variety of operating systems. Most importantly, for image data, an accurate FITS header will facilitate co-registration with RHESSI images and other synoptic datasets.
The minimum FITS keywords to ensure a viable file are:
1. XCEN, YCEN - coordinates of center of image relative to Sun center in CDELT1 and CDELT2 units, respectively, at the time corresponding to DATE-OBS. Sun center is considered the origin (0,0), with North and West corresponding to positive directions. Note that, although XCEN and YCEN are not FITS standards, they are useful for allowing co-registration of images.
As shown in the sample header, there are additional FITS keywords which should be included to help identify the associated data.
Store files in an anonymous FTP directory that is organized by date. A recommended method is to store files in subdirectories arranged by day. The following example uses yymmdd to name each daily subdirectory:
```
Current directory is /pub/data/bbso/fits

 000101/
 000102/
 000103/
 000104/
 000105/
 000106/
 000107/
 000108/
 000109/
 000110/
 000111/
 000112/
 000113/
 ......
```
The advantage of the above method is that it facilitates remote searching and copying of files (e.g. by mirroring).

Use a date-based file naming convention. The example below is a suggested format for a Big Bear H-alpha full disk image observed at 15:41 on 20 August 1999 that is based upon the IAU naming system.



    bbso_halph_fd_19990820_1541.fts  
    ---- ----- -- -------- ---- ---
      |    |    |     |      |   |
      |    |    |     |      |   |
      |    |    |     |      |  File extension (3 chars)
      |    |    |     |      |
      |    |    |     |   Observation time (4 chars, in hhmm format)
      |    |    |     |
      |    |    |  Observation date (8 chars, in yyyymmdd format)
      |    |    |
      |    |  Miscellaneous info code (2 chars)
      |    |
      |  Image type code (5 chars)
      |
    Observatory or instrument code (4 chars)

It is recommended that as much self-descriptive information about the file be embedded in the file name. At the very minimum, the file name should include a date string such as yyyymmdd_hhmm The advantage of such a naming system is that it facilitates locating and identifying a particular file without reading its contents.

Optional: For each subdirectory in which files are stored, include an ASCII README file which lists the files in each directory, together with additional information such as observed GOES events and NOAA active region numbers. The following is a suggested format for the README file, in which field values are separated in columns delimited by a | and repeat row values are denoted by ".
```
  FILENAME                         TYPE    SUB-TYPE        GOES              NOAA 
             
bbso_halpha_fd_19990616_1140.fts | Image | Optical  | 11:00 M3.6         | 8569 
bbso_halpha_fd_19990616_1145.fts |   "   |    "     |                    |
bbso_halpha_fd_19990616_1240.fts |   "   |    "     | 12:50 C1           | 8569   
bbso_halpha_fd_19990616_1440.fts |   "   |    "     |                    |
bbso_halpha_fd_19990616_1540.fts |   "   |    "     | 15:40 C3, 15:50 M3 |    
bbso_halpha_fd_19990616_1740.fts |   "   |    "     |                    | 8570, 8571
```
The FILENAME field contains the individual names of each data file in the date-based convention recommended above. If a different preferred naming convention is used, then the README file should contain an additional DATE_OBS column with the corresponding date/time value for each file.
The TYPE field contains values that describe the type of data within the file. Suggested values are:
Image, Spectrum, Lightcurve, or Scan.
The SUB-TYPE field contains information on the wavelength/energy category of the data. Suggested values are:
Gamma-Ray, Hard X-ray, Soft X-ray, XUV, EUV, UV, Optical, Infra-red, Radio.
The GOES field value contains the peak time and intensity of an identified GOES event that the data pertains to. The NOAA field value contains the active region number of an identified region that the data pertains to. Multiple values of these fields are permitted.
The advantage of supplying a README file is that it can be imported into the RHESSI Synoptic Data Archive and jointly queried together with RHESSI and other ancillary datasets as is currently done in the Max Millennium Flare Catalog .

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