International Comet Quarterly

Below is 2023 ICQ Comet Handbook (now online only):

Below is 2024 ICQ Comet Handbook (now online only):

Below is 2025 ICQ Comet Handbook (now online only):

We will be adding some pre-publication items here because of their urgency or time-sensitive nature for observers. Such items available so far:

• "Forward-Scattering Enhancement of Comet Brightness. III. Prospects for C/2010 X1 (Elenin) as Viewed from the Earth and the SOHO, STEREO-A, and STEREO-B Spacecraft", by Joseph N. Marcus (pdf file available here). (posted 8/3/11)
• "Comet 169P/NEAT: Prospects for Forward-Scattering Brightness Enhancement in December 2009 and Visual Observation of the Bare Nucleus as Early as Mid-January 2010", by Joseph N. Marcus (pdf file available here). [also, scanned images of individual pages: page 1 / page 2 / page 3 / page 4 / page 5 / page 6 / page 7 / page 8 ] (posted 12/15/09)

Starting in late 2006, we are posting the full tabulated list of photometric observations at the time of publication of the regularly quarterly issues of the ICQ, at this separate webpage.

We are gradually adding other published ICQ articles to this website. Those available so far:

• "Comet 12P/Pons-Brooks: Identification with Comets C/1385 U1 and C/1457 A1", by Maik Meyer, Takao Kobayashi, Syuichi Nakano, and Daniel W. E. Green (2011), ICQ 33, 115-127 [12.4-MB pdf file].
• "In Remembrance of Brian Marsden", by Zdenek Sekanina (2011), ICQ 33, 26-27 [8.7-MB pdf file].
• "In Remembrance of Brian G. Marsden", by Maik Meyer (2011), ICQ 33, 25-26 [5.6-MB pdf file].
• "In Remembrance of Brian Marsden", by Albert Jones (2011), ICQ 33, 25 [1.8-MB pdf file].
• "Brian G. Marsden (1937-2010): Invited Memorial Service Talk, 2011 January 16", by Irwin Shapiro (2011), ICQ 33, 19 [4-MB pdf file].
• "A Tribute to the Memory of Brian G. Marsden", by John T. Ramsey (2011), ICQ 33, 7-8 [7.8-MB pdf file].
• "Remembering Brian Marsden", by Owen Gingerich (2011), ICQ 33, 6 [3.4-MB pdf file].
• "Review of Recent Literature: Research Concerning Comets", by Carl W. Hergenrother (2010), ICQ 32, 83-85 [10.7-MB pdf file].
• "Recurrence of Super-Massive Explosions and Orbital Evolution of Comet 17P/Holmes: II. Search for Historical Records, and Outlook for Future Research", by Zdenek Sekanina (2010), ICQ 32, 3-32 first half (pp. 3-15) [59-MB pdf file]; second half (pp. 16-32) [73-MB pdf file].
• "Crystallization of Gas-Laden Amorphous Water Ice, Activated by Heat Transport to its Subsurface Reservoirs, as Trigger of Huge Explosions of Comet 17P/Holmes", by Zdenek Sekanina (2009), ICQ 31, 99-124 [2.5-MB pdf file].
• "Comets for the Visual Observer in 2010", by Alan Hale (2009), ICQ 31, 84-86 [2.2-MB pdf file].
• "Recurrence of Super-Massive Explosions and Orbital Evolution of Comet 17P/Holmes: I. Missed 1913-1957 Returns to the Sun", by Zdenek Sekanina (2009), ICQ 31, 45-65 [4.3-MB pdf file].
• "Comet 17P/Holmes: A Megaburst Survivor", by Zdenek Sekanina (2009), ICQ 31, 5-23 [6.7-MB pdf file].
• "Unpublished Observations of the Eclipse Comet, C/1948 V1", by F. Lancaster Hiett, Michael Saladyga, and Thomas R. Williams (2008), ICQ 30, 140- 141 [jpeg files].
• "Palestinian Observations of the Comet of 1577", by S. M. Silverman (2008), ICQ 30, 123-124. [postscript file].
• "On a Forgotten 1836 Explosion from Halley's Comet, Reminiscent of 17P/Holmes' Outbursts", by Zdenek Sekanina (2008), ICQ 30, 63-74 [1.3-MB pdf file].
• "Exploding Comet 17P/Holmes", by Zdenek Sekanina (2008), ICQ 30, 3-28 (includes 1-page tabulation of ``Photometry of Deep-Sky Objects" of relevance) [large, 41-MB pdf file]. Correction to the printed text in the last paragraph of text on page 26, line 3 (before the Acknowledgements): FOR terrain, one by is an efficient READ terrain, one by one, is an efficient
• "Forward-Scattering Enhancement of Comet Brightness. II. The Light Curve of C/2006 P1", by Joseph N. Marcus (2007), ICQ 29, 119-130 [1.3-MB pdf file].
• "Forward-Scattering Enhancement of Comet Brightness. I. Background and Model", by Joseph N. Marcus (2007), ICQ 29, 39-66 [WARNING: very large pdf file (50 megabytes)].
• "Halley's First Name: Edmond or Edmund", by David W. Hughes and Daniel W. E. Green (2007), ICQ 29, 7-14 [938-kB pdf file].
• "Charles Messier, Napoleon, and Comet C/1769 P1", by Maik Meyer (2007), ICQ 29, 3-6 [533-kB pdf file].
• "Comet 73P/Schwassmann-Wachmann: Nucleus Fragmentation, Its Light-Curve Signature, and Close Approach to Earth in 2006", by Zdenek Sekanina (2005), ICQ 27, 225-240 [1.85-MB pdf file].
• "Fred Lawrence Whipple (1906-2004)", by Daniel W. E. Green (2004), ICQ 26, 115-118 [24-MB pdf file].
• "The Comet of 1577 and a Turkish-Ottoman Astronomer", by Haldun I. Menali and Ahmed Suheyl Unver (2004), ICQ 26, 3-7 [offsite html webpage pointing to gif images of each individual article page].
• "What Happened to Comet C/2002 O4 (Hoenig)?", by Zdenek Sekanina (2002), ICQ 24, 223-236 [64-MB pdf file].
• "CCD Photometry of Comet C/1995 O1 (Hale-Bopp): 1995-2000", by William Liller (2001), ICQ 23, 93-97 [11.6-MB pdf file].
• "Correlation Between Visual Magnitudes and the Outgassing Rate of CO in Comets Beyond 3 AU", by Nicolas Biver (2001), ICQ 23, 85-93 [48-MB pdf file].
• "Book Review: Solar System Astronomy in America -- Communities, Patronage, and Interdisciplinary Research, 1920-1960", by Daniel W. E. Green (1999), ICQ 21, 44-46.
• Primer on CCD photometry of comets, from the ICQ's 1997 Guide to Observing Comets, pp. 94-104 [html page].
• "New Designations for Old", by Brian G. Marsden (1995), ICQ 17, 3-6 [pdf version of entire 4-page article] ; ICQ 17, 3 [gif/html page; only the first page of four total].
• "Magnitude Corrections for Atmospheric Extinction", by Daniel W. E. Green (1992), ICQ 14, 55-59 [html page].
• "Some Thoughts on Limiting Visual Stellar and Cometary Magnitudes with Various Apertures", by Daniel W. E. Green (1985), ICQ 7, 40-46 [scanned images of individual pages: page 40 / page 41 / page 42 / page 43 / page 44 / page 45 / page 46 /

COMPLETE ISSUES OF THE ICQ::

• The entire August 1978 issue of the Comet Quarterly (Whole Number 28) is available here.

Note: in 1979, the name of this publication changed from the Comet Quarterly to the International Comet Quarterly (ICQ).

• The entire January 1979 issue of the ICQ (Whole Number 29) is available here.
• The entire April 1979 issue of the ICQ (Whole Number 30) is available here.
• The entire July 1979 issue of the ICQ (Whole Number 31) is available here.
• The entire Oct. 1979 issue of the ICQ (Whole Number 32) is available here.

• The entire January 1980 issue of the ICQ (Whole Number 33) is available here.
• The entire April 1980 issue of the ICQ (Whole Number 34) is available here.
• The entire July 1980 issue of the ICQ (Whole Number 35) is available here.
• The entire Oct. 1980 issue of the ICQ (Whole Number 36) is available here.

• The entire January 1981 issue of the ICQ (Whole Number 37) is available here.
• The entire April 1981 issue of the ICQ (Whole Number 38) is available here.
• The entire July 1981 issue of the ICQ (Whole Number 39) is available here.
• The entire Oct. 1981 issue of the ICQ (Whole Number 40) is available here.

• The entire January 1982 issue of the ICQ (Whole Number 41) is available here.
• The entire April 1982 issue of the ICQ (Whole Number 42) is available here.
• The entire July 1982 issue of the ICQ (Whole Number 43) is available here.
• The entire Oct. 1982 issue of the ICQ (Whole Number 44) is available here.

• The entire January 1983 issue of the ICQ (Whole Number 45) is available here.
• The entire April 1983 issue of the ICQ (Whole Number 46) is available here.
• The entire July 1983 issue of the ICQ (Whole Number 47) is available here.
• The entire Oct. 1983 issue of the ICQ (Whole Number 48) is available here.

• The entire January 1984 issue of the ICQ (Whole Number 49) is available here.
• The entire April 1984 issue of the ICQ (Whole Number 50) is available here.
• The entire July 1984 issue of the ICQ (Whole Number 51) is available here.
• The entire Oct. 1984 issue of the ICQ (Whole Number 52) is available here.

• The entire Jan. 1985 issue of the ICQ (Whole Number 53) is available here.
• The entire April 1985 issue of the ICQ (Whole Number 54) is available here.
• The entire July 1985 issue of the ICQ (Whole Number 55) is available here.
• The entire Oct. 1985 issue of the ICQ (Whole Number 56) is available here.

• The entire January 1986 issue of the ICQ (Whole Number 57) is available here.
• The entire April 1986 issue of the ICQ (Whole Number 58) is available here.
• The entire July 1986 issue of the ICQ (Whole Number 59) is available here.
• The entire Oct. 1986 issue of the ICQ (Whole Number 60) is available here.

• The entire January 1987 issue of the ICQ (Whole Number 61) is available here.
• The entire April 1987 issue of the ICQ (Whole Number 62) is available here.
• The entire July 1987 issue of the ICQ (Whole Number 63) is available here.
• The entire Oct. 1987 issue of the ICQ (Whole Number 64) is available here.

• The entire January 1988 issue of the ICQ (Whole Number 65) is available here.
• The entire April 1988 issue of the ICQ (Whole Number 66) is available here.
• The entire July 1988 issue of the ICQ (Whole Number 67) is available here.
• The entire Oct. 1988 issue of the ICQ (Whole Number 68) is available here.

• The entire January 1989 issue of the ICQ (Whole Number 69) is available here.
• The entire April 1989 issue of the ICQ (Whole Number 70) is available here.
• The entire July 1989 issue of the ICQ (Whole Number 71) is available here.
• The entire Oct. 1989 issue of the ICQ (Whole Number 72) is available here.

• The entire January 1990 issue of the ICQ (Whole Number 73) is available here.
• The entire April 1990 issue of the ICQ (Whole Number 74) is available here.
• The entire July 1990 issue of the ICQ (Whole Number 75) is available here.
• The entire Oct. 1990 issue of the ICQ (Whole Number 76) is available here.

• The entire January 1991 issue of the ICQ (Whole Number 77) is available here.
• The entire April 1991 issue of the ICQ (Whole Number 78) is available here.
• The entire July 1991 issue of the ICQ (Whole Number 79) is available here.
• The entire Oct. 1991 issue of the ICQ (Whole Number 80) is available here.

• The entire January 1992 issue of the ICQ (Whole Number 81) is available here.
• The entire April 1992 issue of the ICQ (Whole Number 82) is available here.
• The entire July 1992 issue of the ICQ (Whole Number 83) is available here.
• The entire Oct. 1992 issue of the ICQ (Whole Number 84) is available here.

• The entire January 1993 issue of the ICQ (Whole Number 85) is available here.
• The entire April 1993 issue of the ICQ (Whole Number 86) is available here.
• The entire July 1993 issue of the ICQ (Whole Number 87) is available here.
• The entire October 1993 issue of the ICQ (Whole Number 88) is available here.

• The entire January 1994 issue of the ICQ (Whole Number 89) is available here.
• The entire April 1994 issue of the ICQ (Whole Number 90) is available here.
• The entire July 1994 issue of the ICQ (Whole Number 91) is available here.
• The entire October 1994 issue of the ICQ (Whole Number 92) is available here.

• The entire January 1995 issue of the ICQ (Whole Number 93) is available here.
• The entire April 1995 issue of the ICQ (Whole Number 94) is available here.
• The entire July 1995 issue of the ICQ (Whole Number 95) is available here.
• The entire October 1995 issue of the ICQ (Whole Number 96) is available here.

• The entire January 1996 issue of the ICQ (Whole Number 97) is available here.
• The entire April 1996 issue of the ICQ (Whole Number 98) is available here.
• The entire July 1996 issue of the ICQ (Whole Number 99) is available here.
• The entire October 1996 issue of the ICQ (Whole Number 100) is available here.

• The entire January 1997 issue of the ICQ (Whole Number 101) is available here.
• The entire April 1997 issue of the ICQ (Whole Number 102) is available here.
• The entire July 1997 issue of the ICQ (Whole Number 103) is available here.
• The entire October 1997 issue of the ICQ (Whole Number 104) is available here.

• The entire January 1998 issue of the ICQ (Whole Number 105) is available here.
• The entire April 1998 issue of the ICQ (Whole Number 106) is available here.
• The entire July 1998 issue of the ICQ (Whole Number 107) is available here.
• The entire October 1998 issue of the ICQ (Whole Number 108) is available here.

• The entire January 1999 issue of the ICQ (Whole Number 109) is available here.
• The entire April 1999 issue of the ICQ (Whole Number 110) is available here.
• The entire July 1999 issue of the ICQ (Whole Number 111) is available here.
• The entire October 1999 issue of the ICQ (Whole Number 112) is available here.

• The entire January 2000 issue of the ICQ (Whole Number 113) is available here.
• The entire April 2000 issue of the ICQ (Whole Number 114) is available here.
• The entire July 2000 issue of the ICQ (Whole Number 115) is available here.
• The entire October 2000 issue of the ICQ (Whole Number 116) is available here.

• The entire January 2001 issue of the ICQ (Whole Number 117) is available here.
• The entire April 2001 issue of the ICQ (Whole Number 118) is available here.
• The entire July 2001 issue of the ICQ (Whole Number 119) is available here.
• The entire October 2001 issue of the ICQ (Whole Number 120) is available here.

• The entire January 2002 issue of the ICQ (Whole Number 121) is available here.
• The entire April 2002 issue of the ICQ (Whole Number 122) is available here.
• The entire July 2002 issue of the ICQ (Whole Number 123) is available here.
• The entire October 2002 issue of the ICQ (Whole Number 124) is available here.

• The entire January 2003 issue of the ICQ (Whole Number 125) is available here.
• The entire April 2003 issue of the ICQ (Whole Number 126) is available here.
• The entire July 2003 issue of the ICQ (Whole Number 127) is available here.
• The entire October 2003 issue of the ICQ (Whole Number 128) is available here.

• The entire January 2004 issue of the ICQ (Whole Number 129) is available here.
• The entire April 2004 issue of the ICQ (Whole Number 130) is available here.
• The entire July 2004 issue of the ICQ (Whole Number 131) is available here.
• The entire October 2004 issue of the ICQ (Whole Number 132) is available here.

• The entire January 2005 issue of the ICQ (Whole Number 133) is available here.
• The entire April 2005 issue of the ICQ (Whole Number 134) is available here.
• The entire July 2005 issue of the ICQ (Whole Number 135) is available here.
• The entire October 2005 issue of the ICQ (Whole Number 136) is available here.

• The entire January 2006 issue of the ICQ (Whole Number 137) is available here.
• The entire April 2006 issue of the ICQ (Whole Number 138) is available here.
• The entire July 2006 issue of the ICQ (Whole Number 139) is available here.
• The entire October 2006 issue of the ICQ (Whole Number 140) is available here.

• The entire January 2007 issue of the ICQ (Whole Number 141) is available here.
• The entire April 2007 issue of the ICQ (Whole Number 142) is available here.
• The entire July 2007 issue of the ICQ (Whole Number 143) is available here.
• The entire October 2007 issue of the ICQ (Whole Number 144) is available here.

• The entire January 2008 issue of the ICQ (Whole Number 145) is available here.
• The entire April 2008 issue of the ICQ (Whole Number 146) is available here.
• The entire July 2008 issue of the ICQ (Whole Number 147) is available here.
• The entire October 2008 issue of the ICQ (Whole Number 148) is available here.

• The entire January 2009 issue of the ICQ (Whole Number 149) is available here.
• The entire April 2009 issue of the ICQ (Whole Number 150) is available here.
• The entire JulyOctober 2009 issue of the ICQ (Whole Numbers 151 and 152) is available here.

• The entire January 2010 issue of the ICQ (Whole Number 153) is available here.
• The entire April 2010 issue of the ICQ (Whole Number 154) is available here [large 21.4-MB pdf file].

Below are representative non-"paper" sections in pdf format, to show how they appear in print:

• "Descriptive Information, to Complement the Tabulated Data", with illustrations, in the January 2007 issue: ICQ 29, 14-22 [1.6-MB pdf file].
• Cover page and editorial-information page for January 2008 issue: ICQ 30, 1-2 [158.5-kB pdf file].
• "Descriptive Information, to Complement the Tabulated Data", with illustrations, in the January 2008 issue: ICQ 30, 30-46 [large, high-resolution, 40-MB pdf file].
• Tabulated summaries of photometric data for January 2008 issue (the full tabulated data of which appear at this separate webpage): ICQ 30, 47-60 [665-kB pdf file].

[last updated 2025 June 28]