Astronomy:CCOR-1

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CCOR-1 (for Compact CORonograph-1) is a space-based coronograph aboard a geostationary satellite GOES-19 owned by NOAA.[1] Its goal is providing realtime solar data used for space weather forecasting.

It is the first out of planned three coronographs from Compact Coronograph series. CCOR-2 will start its operations in April 2026.

By covering the Sun's extremely bright surface (photosphere) allows observations of its atmosphere called corona.[2][3] It is millions of times fainter than the Sun itself, its surface brightness roughly comparable to full Moon's.[4][5][6][7][8][9] It is important to monitor the corona because coronal mass ejections (CME) can damage electric devices like transformers or power grids.[2][10]

Mission

The instrument's goal is obtaining white light images of the solar corona and downlinking the data within 30 minute latency.[11][12][13][14][15][2] The data is then used to make a space weather forecast.[1][11][14] CCOR's purpose is also replacing aging research coronographs like SOHO/LASCO or STEREO/COR.[12][2]

It was launched on 25 June 2024 5:26 PM EDT using Falcon Heavy rocket from John F. Kennedy Space Center.[11][16][17][2] On 19 September 2024 it obtained its first light image, however it was made public on 22 October.[18][19][20][21] The instrument (and the entire satellite) was handed over to NOAA on 29 January 2025.[22]

On 7 April 2025 it was declared an official operational satellite on GOES-East, located at 75.2°W longitude.[22][11][23]

It is on a geostationary orbit which means that the angular motion of the satellite is equal to Earth's, therefore the object seems to „hang" above a specific spot on the planet. This orbit is placed 35,786 kilometers (22,236 miles) above the equator.

Technicals

  • Prepared for shock testing
    Prepared for shock testing
  • After magnetic characterization
    After magnetic characterization
  • Electromagnetic testing
    Electromagnetic testing
  • Other image from shock testing
    Other image from shock testing

CCOR-1 was developed and tested by US Naval Research Laboratory (NRL).[11][2][13] It is placed on a Sun Pointing Platform (SPS) specifically designed for solar instruments.[11][13][2] It is mounted aside EXIS and SUVI.[11][2]

CCOR-1 from outside. Source: Naval Research Laboratory

Since the instrument is flying on geocentric orbit, it experiences eclipses once a day.[16][15][2] Around 20 days before and after any equinox, the Earth eclipses half of the images.[15] CCOR-1 performs a 180-degree roll maneuver called yawflip to decrease solar array stray light in the camera.[15]

Requirements

The list of requirements that the instrument has to follow is written below:[11]

Note:

B⊙ stands for solar surface brightness ≈ –10.8 mag/arcsec 2

R⊙ is Sun's radius = 695,700 kilometres (432,300 miles) = 0.266°. The FOV is measured at 1 AU (149.6 million km; 93.0 million mi), counted from the outermost edge of the star.

  • FOV of 3.7 – 17≤ R⊙
  • S/N ratio of 10 for 5.1 R⊙ – 21.0 R⊙(1.36° – 5.6°) and spatial resolution of ≤ 50 arcseconds
  • Visible light bandpass
  • Accuracy of measurements of solar corona brightness down to 10% error or better
  • Minimum solar corona intensity of 1.0×10−11B⊙
  • Maximum solar corona intensity of 1.0×10−8B⊙
  • Cadence of 15 minutes for full resolution images and 5 minutes for 2×2 binned
  • Latency of ≤30 minutes
  • Capability for meeting all mission requirements during solar storm of intensity S4 and flare intensity of X50
  • Inner geometric cutoff of 3.7 R⊙
  • CME velocity estimate with ≤5% error for 200–3,400 km/s (120–2,110 mi/s; 450,000–7,610,000 mph)
  • CME mass estimate with ≤ 50% error for 1.0×107 kg to 5.0×1014 kg range
  • Coronal brightness measurement of ≤10% error
  • Reclosable door for possible 5 year on orbit storage
  • Mission of 5 years length with 5 years of resources

Specifications

The actual specifications are:[11][13][14][15][12][24]

Parameter Value
Mass 25 kg (55.1 lb) entire instrument
Power System Box mass 2.3 kilograms (5.1 pounds)
Pixel size 10 µm × 10 µm
Power 22.5 W
Focal length 109.53 mm
Plate scale 19.33"/px in inner FOV | 19.10"/px in outer FOV
Detector pixels 2048 × 1920 px
FOV in degrees (width, height) 10.8°, 10.2°
Inner FOV geometric cutoff 3.7 R⊙(0.984°)
Inner FOV photometric cutoff (S/N ratio ≥ 1) 4.0 R⊙
Outer side FOV (radially from the Sun surface) 18.8 R⊙
Outer diagonal FOV 22.5 R⊙
Spatial resolution ≤50 arcseconds at ≥10% MTF
Field with this resolution 5 R⊙ – 20 R⊙
Bandpass FWHM 470 – 740 nm
Bandpass 450 – 750 nm / 480 – 730 nm (different sources)
Vignetting FOV to 17.4 R⊙
F-number 6.84
Number of occulting disks 19
Cadence in full resolution 15 minutes
Latency ≤15 minutes
Operational temperature −35 degrees Celsius (−31 degrees Fahrenheit)
Boot mode length 65 – 130 seconds
Telemetry modes 3 – Housekeeping, Science, Engineering
Data transfer speed 25 kilobits per second (average)
Solar eclipse of 2025-09-21 seen by CCOR-1 coronagraph onboard GOES-19.

Coronal mass ejection detection

CMEs are detected by PyCat – open-source software created by NOAA/SWPC and UK Met Office.[25] It is a modernized version of older CAT. PyCat studies the morphology of the event from L1 files (check Ground Processing Algorithm below) and compares its appearance from different satellites. Using this data, it can calculate speed, mass and direction of CME.

Ground Processing Algorithm

In order for the raw images from the coronograph to be usable, they have to be processed upon being received. The data sent to the ground by SWPC is already compressed into FITS format files.[15] CCOR-1 images have six processing levels.

First processing level is called L0. It is the raw readout of packets from the detector and metadata (header).[15] From L0 two L0A files are assembled. These are inner FOV and outer FOV parts of image. After L0A images are combined and rotated so solar north is pointing upwards, a L0B file is created.[15]

L0B then undergoes several processings. These are as follows:[15]

  • Reconstructing the onboard bias subtraction
  • Correcting associated with detector linearity
  • Division by exposure time
  • Time normalization
  • Storing factor of calibration (Data Unit/s/px –> MSB)
  • Converting the brightness to MSB (Mean Solar Brightness)
  • Vignetting correction

These calibrations create L1A file. L1A serves as the source for creating models, i.e. earthshine and median background. Earthshine is computed from L1A and then used for subtraction from the image and that creates L1B. It is the only level available in real time.[15]

Example filenames

  • CCOR_0A_20251002T000025_V00_N2.fits
  • CCOR_1A_20251002T000025_V00_NC.fits
  • CCOR_1B_20251002T000025_V00_NC.fits
  • CCOR_2_20251002T000025_V00_NC.fits

Median background

L1A is used for median background determination. A median background of the entire day is called Daily Median (DM). After that, a minimum background is calculated to mirror a slowly changing stray light and F-corona (F-corona is Sun's light reflected of dust particles). 14 days of median background create Monthly Minimal Background (MM), while 7 days is called Minimal background. L1 products then get processed by subtracting either to get L2 level. L2 binned to 2×2 is L3.[15]

Comet discoveries

File:First CCOR-1 comet discovery.webm CCOR-1 allows observations of near Sun comets, especially sungrazers.[26] The first discovery was a Kreutz comet found by an US citizen scientist Robert Pickard on 11 February 2025. It was accompanied by two fragments.[27]

By 11 July 2025, 70 comet discoveries were confirmed and acknowledged via NASA's Sungrazer Project program.[28]

References

  1. ↑ 1.0 1.1 "CCOR │ GOES-R Series". https://www.goes-r.gov/spacesegment/CCOR.html. 
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 "New Coronagraph on GOES-U Will Enhance Space Weather Forecasting" (in en). 2026-02-17. https://www.nesdis.noaa.gov/news/new-coronagraph-goes-u-will-enhance-space-weather-forecasting. 
  3. ↑ "The science of solar eclipses" (in en). https://www.esa.int/Science_Exploration/Space_Science/The_science_of_solar_eclipses. 
  4. ↑ "When 99.9% just isn't good enough | College of Sciences" (in en-US). https://sciences.utsa.edu/physics-astronomy/eclipse.html. 
  5. ↑ Habbal, Shadia; Druckmüller, Miloslav, Hiding the Sun: Coronal Discoveries during Total Solar Eclipses, Scientia, https://www.scientia.global/wp-content/uploads/Shadia_Habbal/Shadia_Habbal.pdf .
  6. ↑ "Physical Properties of 29 March 2006 Solar Corona" (in en). https://arxiv.org/html/2510.08057v1. 
  7. ↑ Landis, Geoffrey A. (2016-04-23), Mission to the Gravitational Focus of the Sun: A Critical Analysis, arXiv, doi:10.48550/arXiv.1604.06351, arXiv:1604.06351, http://arxiv.org/abs/1604.06351, retrieved 2026-02-28 
  8. ↑ Pintér, T.; Klocok, L.; Minarovjech, M.; Rybanský, M. (September 2003). "The total brightness of the solar corona during the eclipse June 21st 2001". Solar variability as an input to the Earth's environment. International Solar Cycle Studies (ISCS) Symposium. https://articles.adsabs.harvard.edu/pdf/2003ESASP.535..243P. 
  9. ↑ Karttunen, Hannu, ed (2020). Astronomia ogólna (Wydanie I - dodruk 1 ed.). Warszawa: PWN. ISBN 978-83-01-20808-0. OCLC 1204357330. https://www.worldcat.org/title/1204357330. 
  10. ↑ Strugarek, Antoine; Janitzek, Nils; Lee, Arrow; Löschl, Philipp; Seifert, Bernhard; Hoilijoki, Sanni; Kraaikamp, Emil; Mrigakshi, Alankrita Isha et al. (2015). "A Space Weather mission concept: Observatories of the Solar Corona and Active Regions (OSCAR)" (in en). Journal of Space Weather and Space Climate 5: A4. doi:10.1051/swsc/2015003. ISSN 2115-7251. https://www.swsc-journal.org/articles/swsc/abs/2015/01/swsc140008/swsc140008.html. 
  11. ↑ 11.0 11.1 11.2 11.3 11.4 11.5 11.6 11.7 11.8 Thernisien, A. F.; Chua, D. H.; Carter, M. T.; Rich, N. B.; Noya, M.; Babich, T. A.; Crippa, C. E.; Baugh, B. et al. (2025-10-04), The CCOR Compact Coronagraphs for the Geostationary Operational Environmental Satellite-19 (GOES-19) and the Space Weather Follow On (SWFO) Missions, arXiv, doi:10.48550/arXiv.2508.13467, arXiv:2508.13467, http://arxiv.org/abs/2508.13467, retrieved 2026-02-28 
  12. ↑ 12.0 12.1 12.2 "WMO OSCAR | Details for Instrument CCOR-1". https://space.oscar.wmo.int/instruments/view/ccor_1. 
  13. ↑ 13.0 13.1 13.2 13.3 Geostationary Operational Environmental Satellite – R Series (GOES-U) - GOES-U Data Book, Lockheed Martin, 11 November 2024, https://www.goes-r.gov/downloads/resources/documents/GOES-U%20DataBook.pdf .
  14. ↑ 14.0 14.1 14.2 "Compact Coronagraph 1 (CCOR-1)". https://ccor.nrl.navy.mil/ccor1-inst-overview. 
  15. ↑ 15.00 15.01 15.02 15.03 15.04 15.05 15.06 15.07 15.08 15.09 15.10 GOES-19 CCOR-1 Data Release Provisional Data Quality Read-Me for Data Users, 5 March 2025, https://www.nesdis.noaa.gov/s3/2025-03/CCOR-1-Provisional-Read-Me-03_12_2025.pdf 
  16. ↑ 16.0 16.1 Miles, Nathan; Vassiliadis, Dimitris (18 March 2025), "Space Weather Follow On: Release of CCOR-1 Imagery and Readiness for the SWFO-L1 Launch", Space Weather Workshop 2025, https://www.swpc.noaa.gov/sites/default/files/images/u97/miles-nathan%2C%20vassiliadis-dimitrios.pdf .
  17. ↑ "NRL's CCOR-1 Instrument Captures Its First Images of the Sun's Atmosphere" (in en-US). U.S. Naval Research Laboratory. https://www.nrl.navy.mil/Media/News/Article/3942042/nrls-ccor-1-instrument-captures-its-first-images-of-the-suns-atmosphere/. 
  18. ↑ "NOAA Shares Imagery From World’s First Operational Space-based Coronagraph" (in en). 2026-02-17. https://www.nesdis.noaa.gov/news/noaa-shares-imagery-worlds-first-operational-space-based-coronagraph. 
  19. ↑ "NOAA's GOES-19 Captures Extended Images of the Sun's Atmosphere" (in en). 2026-02-17. https://www.nesdis.noaa.gov/news/noaas-goes-19-captures-extended-images-of-the-suns-atmosphere. 
  20. ↑ "NRL's CCOR-1 Instrument Captures Its First Images of the Sun's Atmosphere" (in en-US). U.S. Naval Research Laboratory. https://www.nrl.navy.mil/Media/News/Article/3942042/nrls-ccor-1-instrument-captures-its-first-images-of-the-suns-atmosphere/. 
  21. ↑ NOAA Space Weather - Observations Update, Coordination Group for Meteorological Satellites - CGMS, 3 October 2025, https://www.cgms-info.org/Agendas/GetWpFile.ashx?wid=b3ee2ad1-3528-4167-9795-784ef3ab40fd&aid=dee0b5aa-5339-4ce3-b8fd-21666e11fdb8 .
  22. ↑ 22.0 22.1 "GOES-19 Transition to Operations │ GOES-R Series". https://www.goes-r.gov/users/transitionToOperations19.html. 
  23. ↑ "The GOES-19 Mission | Compact Coronagraph 1 (CCOR1)" (in en). https://ccor.nrl.navy.mil/goes19_overview. 
  24. ↑ "Compact Coronagraph (CCOR)" (in en). 2026-04-02. https://www.nesdis.noaa.gov/our-satellites/currently-flying/goes-east-west/compact-coronagraph-ccor. 
  25. ↑ "PуСАТ: A Next-Generation development of the Space Weather Prediction Center CME Analysis Tool (SWPC_CAT) | Cooperative Programs for the Advancement of Earth System Science (CPAESS)". https://cpaess.ucar.edu/abstract-sww-2024/pusat-next-generation-development-space-weather-prediction-center-cme-analysis#:~:text=To%20that%20end,%20whilst%20continuing%20to%20work,the%20L5%20point%20on%20the%20VIGIL%20satellite.. 
  26. ↑ Prestgard, Trygve (2025-03-30). "Amateur Astronomers are Discovering Comets in Online Data from the GOES-19 Satellite!" (in en). https://skyhuntblog.wordpress.com/2025/03/30/amateur-astronomers-are-discovering-comets-in-online-data-from-the-goes-19-satellite/. 
  27. ↑ "SOHO confirmations for February 2025 and.... | Sungrazer". https://sungrazer.nrl.navy.mil/index.php/confs-Feb2025-CCOR1. 
  28. ↑ "Jun 1 through Jul 11 2025 Confirmations | Sungrazer". https://sungrazer.nrl.navy.mil/confs-Jun-Jul2025. 



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