International Comet Quarterly

The ICQ Comet Information Website

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Primary and secondary information on comets and observing comets:

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This is a key place to begin looking for useful and accurate information regarding news, observations, orbital data, designations and names, and good links regarding comets and related topics [sponsored by the International Comet Quarterly (ICQ)]. (Quick aids: Site map 1/Site map 2 (under revision))

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Click here for recent news regarding comets.

• ICQ published material online from the printed ICQ journal and supplementary articles.
• Astronomical headlines from the publications of the CBAT and MPC regarding comets and other objects.

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The new BIST comet-observing program.

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• Currently-observable comets: ephemerides, elements, and links to magnitude estimates
  • The most recent observation of each recently observed comet (see these notes).
  • Recent comet magnitude estimates
• The brightest comets seen since 1935.
  • The brightest comets of the last two centuries: John Bortle's "Bright-Comet Chronicles" are now available at this website.
• Primer on Comet Names, Comet Designations, Comet Nomenclature
  • Correspondence of Old- and New-Style Designations
  • Permanent periodic-comet numbers (new-style), in alphabetical order (including the old name-numerals) or in numerical order (without the old name-numerals)
  • List of Comet Designations and Names
• Recent comets noted to have split
• What is The International Comet Quarterly?

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Additional information on comets (and related phenomena):

• Observing comets, and observations of comets
  • Ephemerides/elements for all currently-observable comets
  • Brief introduction to comet magnitudes/photometry
    • Definition of comet "magnitude"
    • Helpful information on observing for contributors
    • ICQ format for contributors
    • Recommendations for reference-magnitude sources (to use for comet-magnitude estimates)
  • The ICQ Comet Handbook, a special annual publication giving orbital elements, ephemerides, predicted brightnesses, and (starting with the 2007 edition) observability/elongation diagrams for comets.
  • The 1997 edition of the ICQ Guide to Observing Comets is now out of print, but we hope to have a revised edition available soon. We have had a great many requests for this popular item.
  • How to Report a Comet Discovery
• Lists and Plots regarding Comets
• Glossary of comet and astronomical terms
• Index to the CBAT/MPC/ICQ pages (under revision)

• Recommended links to other Websites that contain useful and original comet (and some meteor) material/information
• Recommended publications to general information on comets

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Trans-Neptunian Objects (TNOs)

• Thoughts on why the term "Kuiper Belt" is inappropriate for TNOs.
• Thoughts on the Status of Pluto.

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• Information on atmospheric fireballs (bright meteors) and meteorites
• Information on the scourge of light pollution, and what you can do to help make the sky a better place to view comets in! Some pages were produced and made available here because of the prominence of this problem to cometary observers.

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About This Service

Here are credits and a user-feedback form.

These pages are light on inline images -- we are considerate of users who may be accessing these pages over slow (modem) connections! They are also intended to be text-browser friendly. We are committed to keeping our pages accessible to as many browsers as possible (a courtesy that we'd like to see many other webmasters imitate!).

Further information is available via e-mail from icqcsc(at)eps.harvard.edu

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New England Light Pollution Advisory Group (NELPAG)