Sungrazer Project: How to discover a Comet?

Previously I’ve written about how you can make astronomical discoveries and also mentioned some Citizen Science Program where you can give your contributions to discoveries. Here’s the article – 10 Citizen Science Programs where you can make Astronomical Discoveries. One such program is NASA’s Sungrazer Project where you can discover comets.

Here’s is a quick walk-through:

Sungrazer Project

Sungrazer Project is a NASA-funded Citizen Science Project where participant analyze pictures from SOHO and STEREO missions. Participants have to look for previously unknown comet in the pictures and report their findings. If object that you reported got verified to be a comet – Congrats! you have discovered a Comet.

Sungrazer Project covers two missions-

  1. SOHO : Solar and Heliospheric Observatory (launched – 1995)
  2. STEREO: Solar Terrestrial Relations Observatory (launched – 2006)

Both SOHO and STEREO are in the orbits around the Sun.


Among many other instruments onboard SOHO, we will be focusing on Large Angle and Spectrometric Coronagraph (LASCO). LASCO studies the structure and evolution of the corona by creating an artificial solar eclipse. It has three Coronagraphs – named C1, C2 and C3. Under Sungrazer Project, we will be focusing on images from C2 and C3.


For sungrazer project, among many instruments onboard STEREO, Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) is considered. Of all instruments onboard SECCHI, Sungrazer Project focuses on images from COR2, HI1 and HI2 telescopes.

Important points to remember here:

  1. We focus on images from SOHO, but STEREO also has helped in discovery of ~100 comets.
  2. Although comets are more likely discovered from LASCO images, extremely bright comets do become (rarely) visible in HI1 of SECHHI, before they are seen in SOHO, even with the data delay.
  3. The Kreutz sungrazers are only in the HI1 field of view for maybe three months of the year due to the orbit of STEREO.
  4. The Kreutz comets are in the COR2 field of view all year, but COR2 is not nearly as sensitive to comets as LASCO C2/C3 are.
  5. C2 is the best camera in which to find a comet. It’s slightly more sensitive than C3 and has smaller pixels (better resolution). However, the Kreutz sungrazers are not always seen well in the C2 field of view at certain times of the year. October – December and April – June are the best months in C2. The Kreutz are in C3 all year round. Other (non-Kreutz) comets can be seen at any time of year in C2.
  6. C2 has smaller field of view but with better resolution as compared to C3.

In short SOHO C2 and C3 are preferred. Most comets are reported using data from these two coronagraphs.

Some useful links:


More information about Sungrazer Project will be added soon!


Published by Anand Krishna

Amateur astronomer and astrophotographer. Interested in astrophoto processing, astrostatistics, comet hunting, visual and radio astronomy.

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