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Picture of GOES-12

 Data Notes
Bullet SXI Operations
The GOES Solar X-ray Imager is integrated into the GOES-12 satellite, whose primary mission is to provide Earth-weather monitoring. The SXI is operated by NOAA's National Environmental Satellite, Data, and Information Service. NOAA's Space Weather Prediction Center (SWPC) receives the telemetry stream directly from SXI onboard GOES-12, processes the data, and integrates the observations into their space weather alert and prediction services. The data are sent in real time to NOAA's National Geophysical Data Center (NGDC) where they are immediately made available to the public, and preserved in a secure archive for future research. Extensive general information about the GOES program is available from NASA's GOES Project Office.
Bullet SXI Observation Sequence
The geosynchronous orbit of GOES allows it to have direct line-of-sight observations of the Sun, 24 hours/day, 7 days/week. The only exception to this, is near equinox, when GOES enters Earth's shadow for up to one hour each day. SXI will collect an image once per minute and the exposure settings follow a sequence that is optimized to observe three primary phenomenon as they are reflected in the Solar atmosphere: coronal structures, active regions, and solar flares.
Bullet GOES Space Weather Mission
NOAA operates a series of meteorology observing satellites known as Geosynchronous Operational Environmental Satellites (GOES). Even though the weather pictures from GOES are seen nightly in our living rooms via the local weather broadcast, few people know that GOES also monitors space weather via its onboard Space Weather Prediction Monitor (SEM) system. Until 2001, NOAA monitored monitored three prominent space weather parameters: energetic particles (EPS), magnetic field (MAG) and the total X-ray output of the Sun (XRS). In the summer of 2001, NOAA also began to monitor the structure of the solar atmosphere via the Solar X-ray Imager (SXI).

The XRS primary function is to provide a sensitive means of detecting the beginning of solar flares--explosive events on the Sun's surface that are fueled by the intense magnetic fields that accompany sunspots. The larger solar flares can cause massive ejections of solar matter which reach all points in the solar system and are measured by EPS. Solar activity can also cause disturbances in the solar wind which can propagate to Earth and disturb our local magnetic field. MAG measures fluctuations near the boundary of that field which are used to correlate with the world-wide system of ground-based magnetometers. SXI measures the X-ray flux of the Sun in a 512 x 512 grid, these million+ pieces of information are then combined to make a single image of the Sun in X-rays.
Bullet GOES SXI File Naming Convention
Image data:
SXI_yyyymmdd_hhmmssfff_pv_nn.FTS (29 characters)
'yyyymmdd_hhmmssfff' UTC date (DATE_OBS). The fff section represents fraction of a second.
'p' data product code, i.e.,
p = 'A' => Level-0
p = 'B' => Level-1 The remainder of the alphabet is available for Level-2 product codes.
'v' processing version code, i.e., Reprocessed data will be differentiated by incrementing the version code.
'nn' satellite ID (i.e., GOES-nn)
Bullet GOES SXI Image Format
SXI archive images will be written in the Flexible Image Transport System (FITS) format.  These files have been designed to be compatible with the SOLARSOFT image processing environment. Libraries for reading FITS are available for many languages including IDL, C, and JAVA.  A nice stand-alone viewer is also available for Windows (FITSview).
Bullet Satellite Specific Data Notes for GOES-12 and GOES-13


Bullet The NOAA Goes-12 Solar X-Ray Imager (SXI) 1. Instrument, Operations, and Data (.6 MB PDF), Dr. Steven Hill, et al.

The NOAA Goes-12 Solar X-Ray Imager (SXI) 2. Performance (3.6 MB PDF), Dr. Vic Pizzo, et al.

Bullet GOES-12 SXI Instrument Specifications
The SXI section (pdf) of the official GOES Data Book contains detailed information about:
  • Instrument Design
  • Operations
  • Imager Performance
  • Telescope Assembly
  • Filters
  • Sun sensor
  • Power

Drawing of SXI instrument

Bullet GOES-12 SXI Instrument Summary
  • The SXI telescope images the sun in wavelengths ranging from soft X-rays to extreme ultraviolet. These filters are available [#, wavelength in angstroms, filter name, (Metadata entry)]
    • 01, 6-65, Poly thin (P_THN_A)
    • 02, UV, UV diffuser
    • 03, 6-65, Poly thin (P_THN_B)
    • 04, 6-60, Poly medium (P_MED_B)
    • 05, 6-20, Be thin (B_THN_B)
    • 06, 6-16, Be medium (B_MED)
    • 07, 6-12, Be thick (B_THK)
    • 08, 0-0, Radiation shield (RDSH)
    • 09, 6-80, Open (OPEN)
    • 10, 6-20, Be thin (B_THN_A)
    • 11, 6-50, Poly thick (P_THK)
    • 12, 6-60, Poly medium (P_MED_A)
  • Each image is a 512 x 512 array with 5 arcsec pixels.
Bullet GOES-12 SXI Metadata
  • The browse display includes a drop list containing a short set of metadata:
    • DATE_OBS - Earth-adjusted time of observation, UT
    • IMG_CODE - Intent of the images:
      • FL = Flares
      • CS = Coronal Structures
      • AR = Active Regions
      • BG = Background
      • TST = Test
      • MSFC = Startup sequence
    • WAVELENGTH - filter name.
    • MCPGAIN - Microchannel Plate detector gain setting in volts.
    • EXP_TIME - measured exposure duration..
    • IMG_WDI - Whole disk intensity (units TBD)
    • IMG_MIN - Image minimum intensity (units TBD)
    • IMG_MAX - Image maximum intensity (units TBD)
    • SAT_PIX - Saturated pixel count.
    • Filename.

A complete copy of the SXI image file header information, for each image, is contained in a relational database. For a description of the content of the metadata, see the Level-0 and Level-1 keyword descriptions.

Bullet GOES-12 Image Sequences Through 2004-12-14.
View a summary (pdf, xls) of all the image sequences taken by SXI, including 2001 post launch tests. The summary lists the first image in each sequence change and provides a brief description of what was done in the sequence (eg., 3-filter patrol, UV-bulb test images, MCP-gain testing, etc.). This information was provided by
Bullet GOES-12 New SXI Coronal Hole Product
Beginning on Dec 15, 2004, NOAA/Space Weather Prediction Center started routine production of a coronal hole image product. This product is created 4 times per day (01:00, 07:00, 13:00, and 19:00 UT), for the purpose of identifying coronal holes, and they become available at approximately 08:00, 14:00, 20:00, and 02:00 UT. Each coronal hole image is created from a sum of 12 hours of images (corrected for solar rotation), spanning the period 6 hours prior to the nominal coronal hole image time to 6 hours after . The coronal hole image is composited from 3-second integration, Level-1 (calibrated) images taken through the Thin Polyimide (PTHN) filter.

The need to create this new product was driven by the loss of the ability to use the SXI Open Filter position and by anomalous high voltage power supply (HVPS) behavior. The inability to use the Open Filter was caused by the failure of at least 1 of the 6 entrance filters that normally shield the SXI optics from visible and ultraviolet light. The HVPS behavior has forced imaging to be conducted at a lower than desired gain.

The SXI Coronal Hole product is now available online. View these data in the Browse and Movie sections. View coverage in the Summary section, and download the data in the Search sections.

Contact if you have questions.

Bullet GOES-12 Links
January 30, 2003: NOAA Press Release: SXI Enters Operations
August 13, 2001: NOAA Press Release: GOES-12 Reaches Orbit.
July 23, 2001: NOAA Press Release: GOES-M Launched.
June 21, 2001: NOAA Press Release: GOES-M Ready for Launch.
June 26, 2001: CNN News Brief

NOAA's Office of Satellite Operations:
Real Time GOES Weather Imagery from the Univ. of Wisconsin:
NOAA's Space Weather Prediction Center:

NASA's GOES Project:

National Solar Observatory:
Sun Facts:
Storms in Space (NPR):
Sun's Corona (NASA):
More Sun's Corona (NASA):
The Sun in X-rays (NASA):

Here's a couple of suggested links from Bright Futures Charter School:
Online Education - The Planets and Space Science
The 8 Planets - Just For Kids

 GOES-NOP SXI Under Construction


The GOES-N SXI, developed by Lockheed Martin Advanced Technology Center (LMATC) in Palo Alto, California, uses a telescope assembly to observe the sun's x-ray emissions and provide early detection and location of flares. These observations allow space weather forecasters to monitor solar features and activities such as solar flares, loops, coronal holes, and coronal mass ejections-clouds of charged particles shooting toward Earth-from the sun. Knowledge of the location and size of these phenomena greatly improves the solar forecaster's ability to predict which solar phenomena may affect the Earth and its atmosphere and to determine when predictions and alerts of space weather conditions that may interfere with ground and space systems should be issued. Space weather can have quite far-reaching effects. NOAA categorizes these as radio blackouts, radiation storms, and geomagnetic storms. Radio blackouts interfere with military and commercial communications and navigation systems. Radiation storms can damage operating spacecraft and expose humans to excessive radiation during high-altitude missions.

Bullet GOES-NOP SXI Instrument Specifications

The GOES NOP overview brochure (4 MB pdf) describes the SXI instrument in general terms beginning on page 17.

Bullet GOES-NOP SXI Instrument Summary
Bullet GOES-NOP SXI Metadata
  • The browse display includes a drop list containing a short set of metadata:
    • DATE_OBS - Earth-adjusted time of observation, UT
    • IMG_CODE - Intent of the images:
      • FL = Flares
      • CS = Coronal Structures
      • AR = Active Regions
      • BG = Background
    • WAVELENGTH - filter name.
    • VERLEVL1 - process version for the Level-1 product
    • Filename.

The header key words for the Level-0 and Level-1 SXI images contain extensive information on the state of the SXI instrument at the moment of collection.

For a description of the SXI FITS header content, see the Level-0 and Level-1 keyword descriptions.

Bullet GOES-NOP Image Sequences
View a summary (pdf, xls) of all the image sequences taken by GOES-N SXI. The summary lists the first image in each sequence change and provides a brief description of what was done in the sequence (eg., 3-filter patrol, UV-bulb test images, MCP-gain testing, etc.). This information is (will be) provided by
Bullet GOES-NOP Links

Read about the GOES N,O, P satellite series:

GOES-N Status:

GOES-N Launch Timeline:

NASA's Live Launch Webcast site:

Mission Overview:

Lockheed Martin  SXI: