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Data Product Descriptions

sha.GONGsite_hdrs

Description

This data series captures the FITS headers of GONG site *zi images as ASCII files stored in SUMS under the headers segment of the corresponding record. The purpose is to be able to analyze key data without having to recover the full FITS images, saving recovery time and minimizing the number of tapes and tape files on which the data are stored. The data records are organized by the three prime keys:

Records are included for all original FITS files, including those whose. headers include the FITS keyword FILLED, indicating that they are only fill files and do not represent metadata for valid images. The number of such files is reflected in the value of the record keyword Filled.

Note that the FITS files from which the headers have been obtained do not include the keyword OFFSET, for the adjusted position angle of solar north on the image. This value must be reconstructed from the value for the keyword HA and the corresponding information for the Site and Day in the data series sha.GONGmrcoy.

Keyword Descriptions

FirstImg
The nominal observing time of the first (valid) image included in the record. (This always corresponds to the first file in the original set.) Note that the nominal observing time of GONG images is 16 seconds after the minute in GPS time, which is 35 seconds after the minute in TAI time. It is between 3 seconds after and 2 seconds before the UTC minute, depending on the era since 2001. Therefore the time reported as the keyword value to the minute in UTC is within a few seconds of the nominal observing time.
LastImg
The nominal observing time of the last (valid) image included in the record. (This always corresponds to the last file in the original set.)
MinRecCt
The minimum number of FITS header keyword cards in the modified headers written to the .fitshdr files in the record segment
MaxRecCt
The maximum number of FITS header keyword cards in the modified headers written to the .fitshdr files in the record segment
ImgCount
The total number of original FITS files and modified FITS header records. written.
Filled
The number of original FITS and modified FITS header records with the FITS keyword FILLED, indicating invalid corresponding image data and metadata.
Source
The DRMS record from which the original FITS files were obtained.
Created
The time at which the record in DRMS was created.

Segment Descriptions

The headers segment is a directory containing two sets of files with extensions .fitshdr and .grhist, one each for each FITS file in the original site-day directory corresponding to a minute between the first and last images, including “Fill” files for which there is no valid image (and much incorrect metadata). The files named *.fitshdr contain copies of all FITS header keyword entries in their original order (including duplicated ones if present), with two exceptions. In order to make them valid FITS files, the NAXIS key value has been changed to 0, and the NAXISn keywords have been suppressed. Also, the keywords GHIST* containing the narrative GRASP history (or the number of such keywords).have been removed. In their place, the *.grhist files contain the concatenated values of the successive GHISTnnn keywords, with only newlines where they exist in the keyword values of the original FITS header cards. There is no copy of the GHISTSEQ keyword value.

Processing Status

The records in this series have been populated from records in sha.dsds[gong+][lev1] with the script ~rick/gong/resarch/populatehdrs using the module justhdrs

As of 23 Feb 2024 the records have been completely populated from their listed starting dates through 2022.12.31:

TypeSiteStart Date
velle2001.04.30
intle2002.07.05
velud2001.10.25
intud2002.06.05
veltd2001.07.30
inttd2002.05.26
velct2001.04.20
intct2002.06.06
velbb2001.03.14
intbb2002.06.13
velml2001.06.16
intml2002.06.05

Archive Status

The default retention time on disc for SUMS data in this series is only 120 days from time of creation. Data are marked to be archived to tape before being removed from disc, and all data have been so archived.

JSOC Series Definition

#=====Global Series Information=====
Seriesname:	sha.GONGsite_hdrs
Description:	"FITS headers from GONG site *zi data"
Author:		"Rick Bogart"
Unitsize:	32
Archive:	1
Retention:	120
Tapegroup:	8
PrimeKeys:	SiteDay, SiteCode, Type
DBIndex:	SiteDay, SiteCode, Type

#=====Links=====

# ===== Keyword list ===== #
# Format:
#   Keyword: , link, , , 
# or
#   Keyword: , , {variable | variable}, {record | segment}, 
#            , , , 

# Prime keys
Keyword: SiteDay,  time,   ts_eq,    record, JD_0, -3, ISO, "Obs Date (local time equivalent)"
Keyword: SiteCode, string, variable, record, "", %s, N/A, "Site abbreviation"
Keyword: Type,     string, variable, record, "", %s, ?, "Data type"

# Variable keys
Keyword: FirstImg, time,   variable, record, JD_0, -1, Z, "Time of first image of day"
Keyword: LastImg,  time,   variable, record, JD_0, -1, Z, "Time of last image of day"
Keyword: MinRecCt, int,    variable, record, -1, %d, N/A, "Minimum Keyword Record count in Primary HDU"
Keyword: MaxRecCt, int,    variable, record, -1, %d, N/A, "Maximum Keyword Record count in Primary HDU"
Keyword: ImgCount, int,    variable, record, -1, %d, N/A, "Total number of FITS files"
Keyword: Filled,   int,    variable, record, -1, %d, N/A, "Number of gap filling FITS files"
Keyword: Source,   string, variable, record, "", %s, N/A, "Source data record"
Keyword: Created,  time,   variable, record, JD_0, 0, Z, "DRMS record creation (ingest) time"

# Prime key slotting info (hidden)
Keyword: SiteDay_step,double,constant, record, 86400.0, %.1f, s, ""
Keyword: SiteDay_epoch,time, constant, record, 2000.01.01_00:00Z, 0, Z, ""

#=====Segments=====

Data: headers, variable, string, 0, "N/A", generic, "FITS headers (truncated)"
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