Comet Chasing in July

Comet chasing is the visual observation of telescopic comets.

News

Improvements

I've made improvements to the program that generates this page.  Up to now the code I developed for SkyTools 3 to predict the visibility of a comet in the eyepiece had only been partially implemented here.  Predicting how much aperture is required to see a comet is a very complex task.  Have a look for yourself: a comparison of the predictions below (such as "visible in small telescopes") to the magnitude of each comet shows just how poor an indicator the magnitude alone really is.  Now, when you read below that a particular aperture is required to see a comet, you can have a reasonable degree of confidence that the comet can in fact be seen in the eyepiece.

 

Make your own custom charts and predictions for your location and equipment: software for comet observing

Comet Synopses for July

Explanation of Comet Synopses and charts (read this if you have questions)  

Charts look poor or grainy? Read this.

C/2008 Q3 (Garradd): An evening comet visible in binoculars
This comet begins the month in Corvus at magnitude 7.5. Look for a 7.5' coma. It should fade by about 1.1 magnitudes, moving into Virgo by month's end. The best visibility is early in the month as seen from the southern hemisphere.  FINDER_CHART
Latitude Visibility July 4 Visibility July 11 Visibility July 18 Visibility July 25 Visibility August 1 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible 1-1, 9-9
40o N Fairly high in the western sky during evening twilight at ~20:50 Low in the western sky during evening twilight at ~21:00 Low in the western sky during evening twilight at ~21:00 Low in the western sky during evening twilight at ~20:50 Low in the western sky during evening twilight at ~20:30 1-
Equator High during evening twilight at ~19:10 High at ~19:30 High at ~19:20 High during evening twilight at ~19:20 High during evening twilight at ~19:10 1-
30o S High during evening twilight at ~18:30 High at ~18:40 High at ~18:50 High in moonlight at ~18:50 High during evening twilight at ~18:40 1-

C/2006 W3 (Christensen): A morning comet visible in binoculars
This comet begins the month in Pegasus at magnitude 8.6. Look for a 2.5' coma. It should brighten slowly, moving into Vulpecula by month's end.  FINDER_CHART
Latitude Visibility July 4 Visibility July 11 Visibility July 18 Visibility July 25 Visibility August 1 Nights Visible
55o N High during morning twilight at ~01:10 High during morning twilight at ~00:20 High during morning twilight at ~00:00 High during morning twilight at ~00:10 High during morning twilight at ~00:10 1-
40o N High at ~02:40 Fairly high at ~21:40 High at ~01:20 High at ~01:00 High at ~01:20 1-
Equator High at ~04:20 High in moonlight at ~02:30 High at ~01:40 High at ~01:00 High at ~03:00 1-
30o S Low in the northern sky at ~05:30 Fairly high in the northern sky in moonlight at ~02:30 Fairly high in the northern sky at ~01:40 Fairly high in the northern sky at ~01:00 Fairly high in moonlight at ~00:00 1-

C/2008 T2 (Cardinal): A southern hemisphere evening comet visible in a 6-inch telescope
This comet begins the month in Hydra at magnitude 8.7. Look for a 4' coma. It should fade by about 0.6 magnitudes, moving into Antlia by month's end. The best visibility is early in the month as seen from the southern hemisphere.  FINDER_CHART
Latitude Visibility July 4 Visibility July 11 Visibility July 18 Visibility July 25 Visibility August 1 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Not visible Not visible Not visible Not visible Not visible  
Equator Low in the western sky during evening twilight at ~19:00 Very low in the western sky during evening twilight at ~19:00 Not visible Not visible Not visible 1-19, 22-26
30o S Fairly high in the western sky during evening twilight at ~18:20 Fairly high in the western sky during evening twilight at ~18:30 Fairly high in the western sky during evening twilight at ~18:40 Fairly high in the western sky during evening twilight at ~18:40 Fairly high in the western sky during evening twilight at ~18:30 1-

217P/LINEAR: A morning comet visible in an 8-inch telescope
This comet begins the month in Aquarius at magnitude 13.3. Look for a 1' coma. It should brighten by about 1.2 magnitudes, moving into Cetus by month's end.  FINDER_CHART
Latitude Visibility July 4 Visibility July 11 Visibility July 18 Visibility July 25 Visibility August 1 Nights Visible
55o N Low in the eastern sky during morning twilight at ~01:10 Low in the eastern sky during morning twilight at ~01:30 Low in the eastern sky during morning twilight at ~01:20 Low in the eastern sky during morning twilight at ~01:30 Low in the eastern sky during morning twilight at ~01:50 1-
40o N Fairly high during morning twilight at ~02:50 Fairly high during morning twilight at ~03:10 Fairly high during morning twilight at ~03:00 Fairly high during morning twilight at ~03:10 Fairly high during morning twilight at ~03:20 1-
Equator High at ~04:40 High during morning twilight at ~04:50 High in moonlight at ~04:40 High at ~04:40 High at ~04:40 1-
30o S High at ~05:30 High in moonlight at ~05:30 High at ~05:10 High at ~05:10 High at ~05:10 1-

22P/Kopff: A morning comet visible in a 10-inch telescope
This comet begins the month in Aquarius at magnitude 9.4. Look for a 8.5' coma. It should fade slowly.  FINDER_CHART
Latitude Visibility July 4 Visibility July 11 Visibility July 18 Visibility July 25 Visibility August 1 Nights Visible
55o N Low in the southern sky during morning twilight at ~01:10 Fairly high in the southern sky during morning twilight at ~01:30 Low in the southern sky during morning twilight at ~00:50 Fairly high in the southern sky during morning twilight at ~01:00 Fairly high in the southern sky during morning twilight at ~01:20 1-
40o N Fairly high during morning twilight at ~02:40 High during morning twilight at ~03:10 High in moonlight at ~02:50 Fairly high at ~02:40 Fairly high at ~02:20 1-
Equator High at ~04:20 High in moonlight at ~04:10 High at ~03:00 High at ~02:40 High at ~03:00 1-
30o S High at ~05:30 High in moonlight at ~04:10 High at ~03:10 High at ~02:40 High at ~04:10 1-

116P/Wild: An evening comet visible in a 10-inch telescope
This comet begins the month in Leo at magnitude 11.6. Look for a 1.5' coma. It should fade slowly, moving into Virgo by month's end.  FINDER_CHART
Latitude Visibility July 4 Visibility July 11 Visibility July 18 Visibility July 25 Visibility August 1 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Low in the western sky during evening twilight at ~20:50 Low in the western sky during evening twilight at ~21:00 Low in the western sky during evening twilight at ~20:50 Low in the western sky during evening twilight at ~20:40 Low in the western sky during evening twilight at ~20:20 1-
Equator High during evening twilight at ~19:10 Fairly high during evening twilight at ~19:20 Fairly high during evening twilight at ~19:20 Fairly high during evening twilight at ~19:20 Fairly high during evening twilight at ~19:10 1-
30o S High during evening twilight at ~18:30 Fairly high during evening twilight at ~18:40 Fairly high during evening twilight at ~18:40 Fairly high during evening twilight at ~18:40 Fairly high during evening twilight at ~18:40 1-

88P/Howell: An evening comet visible in a 10-inch telescope
This comet begins the month in Virgo at magnitude 12.8. Look for a 40" coma. It should brighten by about 0.5 magnitudes by month's end. The best visibility is late in the month as seen from the southern hemisphere.  FINDER_CHART
Latitude Visibility July 4 Visibility July 11 Visibility July 18 Visibility July 25 Visibility August 1 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible 1-4
40o N Fairly high in the western sky during evening twilight at ~21:00 Fairly high in the western sky during evening twilight at ~21:10 Fairly high in the western sky during evening twilight at ~21:00 Low in the western sky during evening twilight at ~20:50 Low in the western sky during evening twilight at ~20:30 1-
Equator High during evening twilight at ~19:10 High at ~19:20 High at ~19:20 High during evening twilight at ~19:20 High during evening twilight at ~19:10 1-
30o S High during evening twilight at ~18:30 High at ~18:40 High at ~18:50 High in moonlight at ~18:50 High during evening twilight at ~18:40 1-

65P/Gunn: An evening comet visible in a 16-inch telescope
This comet begins the month in Virgo at magnitude 12.7. Look for a 1' coma. It should remain constant.  FINDER_CHART
Latitude Visibility July 4 Visibility July 11 Visibility July 18 Visibility July 25 Visibility August 1 Nights Visible
55o N Low in the western sky during evening twilight at ~22:40 Not visible Not visible Not visible Not visible 1-6
40o N Fairly high during evening twilight at ~21:00 Fairly high in the western sky during evening twilight at ~21:10 Fairly high in the western sky during evening twilight at ~21:00 Low in the western sky during evening twilight at ~20:50 Low in the western sky during evening twilight at ~20:30 1-
Equator High during evening twilight at ~19:10 High at ~19:20 High during evening twilight at ~19:20 High during evening twilight at ~19:20 High during evening twilight at ~19:10 1-
30o S High during evening twilight at ~18:30 High at ~18:40 High at ~18:40 High during evening twilight at ~18:50 High during evening twilight at ~18:40 1-

C/2007 Q3 (Siding Spring): A southern hemisphere evening comet visible in very large telescopes
This comet begins the month in Monoceros at magnitude 9.7. Look for a 4' coma. It should brighten slowly, moving into Hydra by month's end. The best visibility is early in the month as seen from the southern hemisphere.  FINDER_CHART
Latitude Visibility July 4 Visibility July 11 Visibility July 18 Visibility July 25 Visibility August 1 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Not visible Not visible Not visible Not visible Not visible  
Equator Not visible Not visible Not visible Not visible Not visible 1-2
30o S Low in the western sky during evening twilight at ~18:10 Very low in the western sky during evening twilight at ~18:20 Very low in the western sky during evening twilight at ~18:20 Not visible Not visible 1-18, 20-21

67P/Churyumov-Gerasimenko: An evening comet visible in very large telescopes
This comet begins the month in Cancer at magnitude 10.7. Look for a 5.5' coma. It should fade by about 0.8 magnitudes, moving into Leo by month's end.  FINDER_CHART
Latitude Visibility July 4 Visibility July 11 Visibility July 18 Visibility July 25 Visibility August 1 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Very low in the western sky during evening twilight at ~20:40 Not visible Not visible Not visible Not visible 1-5
Equator Low in the western sky during evening twilight at ~19:00 Low in the western sky during evening twilight at ~19:10 Very low in the western sky during evening twilight at ~19:10 Very low in the western sky during evening twilight at ~19:10 Not visible 1-29
30o S Low in the western sky during evening twilight at ~18:10 Very low in the western sky during evening twilight at ~18:30 Very low in the western sky during evening twilight at ~18:30 Very low in the western sky during evening twilight at ~18:20 Not visible 1-26

C/2009 E1 (Itagaki): A morning comet visible in very large telescopes
This comet begins the month in Vulpecula at magnitude 11.0. Look for a 5.5' coma. It should fade rapidly, moving into Aquila by month's end.  FINDER_CHART
Latitude Visibility July 4 Visibility July 11 Visibility July 18 Visibility July 25 Visibility August 1 Nights Visible
55o N High during morning twilight at ~01:10 High during morning twilight at ~00:20 High during morning twilight at ~00:00 Fairly high during evening twilight at ~23:40 Fairly high in the southern sky during evening twilight at ~00:00 1-
40o N High at ~02:40 Fairly high at ~21:40 High at ~23:50 High at ~22:50 Fairly high in the western sky at ~01:20 1-
Equator High at ~04:20 Fairly high at ~21:20 High at ~23:50 High at ~22:50 High in moonlight at ~22:00 1-
30o S Fairly high in the western sky at ~05:30 Fairly high in the eastern sky at ~21:10 High at ~23:50 High at ~22:50 High in moonlight at ~22:00 1-

C/2009 F6 (Yi-SWAN): A southern hemisphere morning comet visible in very large telescopes
This comet begins the month in Gemini at magnitude 10.3. Look for a 4' coma. It should fade by about 0.8 magnitudes by month's end. The best visibility is late in the month as seen from the southern hemisphere.  FINDER_CHART
Latitude Visibility July 4 Visibility July 11 Visibility July 18 Visibility July 25 Visibility August 1 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Not visible Not visible Not visible Not visible Not visible  
Equator Not visible Not visible Not visible Not visible Very low in the eastern sky during morning twilight at ~05:10 29-
30o S Not visible Not visible Not visible Not visible Very low in the eastern sky during morning twilight at ~05:40 29-

C/2009 G1 (STEREO): A southern hemisphere evening comet visible in very large telescopes
This comet begins the month in Carina at magnitude 10.7. Look for a 6' coma. It should fade rapidly, moving into Vela by month's end. The best visibility is early in the month as seen from the southern hemisphere.  FINDER_CHART
Latitude Visibility July 4 Visibility July 11 Visibility July 18 Visibility July 25 Visibility August 1 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Not visible Not visible Not visible Not visible Not visible  
Equator Not visible Not visible Not visible Not visible Not visible  
30o S Fairly high in the southern sky during evening twilight at ~18:20 Fairly high in the southern sky during evening twilight at ~18:40 Fairly high in the southern sky during evening twilight at ~18:40 Fairly high in the southern sky during evening twilight at ~18:40 Low in the southern sky during morning twilight at ~05:30 1-

29P/Schwassmann-Wachmann: A southern hemisphere evening comet visible in very large telescopes
This comet begins the month in Cancer at magnitude 12.6. Look for a 1.5' coma. It should remain constant.  FINDER_CHART
Latitude Visibility July 4 Visibility July 11 Visibility July 18 Visibility July 25 Visibility August 1 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Not visible Not visible Not visible Not visible Not visible  
Equator Not visible Not visible Not visible Not visible Not visible 1-3
30o S Not visible Not visible Not visible Not visible Not visible 1-2

C/2006 OF2 (Broughton): A southern hemisphere evening comet visible in very large telescopes
This comet begins the month in Cancer at magnitude 13.1. Look for a 55" coma. It should fade slowly.  FINDER_CHART
Latitude Visibility July 4 Visibility July 11 Visibility July 18 Visibility July 25 Visibility August 1 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Not visible Not visible Not visible Not visible Not visible  
Equator Very low in the western sky during evening twilight at ~19:00 Not visible Not visible Not visible Not visible 1-4, 8-8
30o S Not visible Not visible Not visible Not visible Not visible 1-1

C/2007 G1 (LINEAR): A southern hemisphere morning comet visible in very large telescopes
This comet begins the month in Columba at magnitude 13.4. Look for a 2' coma. It should fade slowly. The best visibility is late in the month as seen from the southern hemisphere.  FINDER_CHART
Latitude Visibility July 4 Visibility July 11 Visibility July 18 Visibility July 25 Visibility August 1 Nights Visible
55o N Not visible Not visible Not visible Not visible Not visible  
40o N Not visible Not visible Not visible Not visible Not visible  
Equator Not visible Not visible Not visible Low in the eastern sky during morning twilight at ~05:00 Low in the eastern sky during morning twilight at ~05:00 21-
30o S Fairly high in the eastern sky during morning twilight at ~05:40 Fairly high in the eastern sky during morning twilight at ~05:40 Fairly high during morning twilight at ~05:30 Fairly high during morning twilight at ~05:30 Fairly high during morning twilight at ~05:20 1-

 

Summary Data for This Month's Telescopic Comets

Here's a list of the comets brighter than 15th magnitude.  This table is updated as necessary.  The last column indicates the date of the last observation used to compute these values.  The constellation listed is where the comet was on the first of the month.
Comet Constellation

July 1st

July 15th

July 31st

 Observations as of (UT)
Mag Diam Mag Diam Mag Diam
C/2008 Q3 (Garradd) Corvus 7.5 8.4' 8.0 6.7' 8.6 5.4' 2009 June 21
C/2006 W3 (Christensen) Pegasus 8.6 2.2' 8.4 2.4' 8.3 2.5' 2009 June 21
C/2008 T2 (Cardinal) Hydra 8.7 4.0' 8.9 4.0' 9.3 3.9' 2009 June 21
22P/Kopff Aquarius 9.4 8.4' 9.6 8.9' 9.9 9.2' 2009 June 21
C/2007 Q3 (Siding Spring) Monoceros 9.7 4.0' 9.6 4.0' 9.5 4.0' 2009 June 14
C/2009 F6 (Yi-SWAN) Gemini 10.3 4.3' 10.7 4.1' 11.1 4.0' 2009 May 27
C/2009 G1 (STEREO) Carina 10.7 6.9' 11.5 5.7' 12.3 4.7' 2009 June 19
67P/Churyumov-Gerasimenko Cancer 10.7 5.9' 11.1 5.6' 11.5 5.2' 2009 May 27
C/2009 E1 (Itagaki) Vulpecula 11.0 5.4' 11.6 5.2' 12.6 4.2' 2009 June 21
116P/Wild Leo 11.6 1.5' 11.7 1.4' 11.8 1.3' 2009 June 21
29P/Schwassmann-Wachmann Cancer 12.6 1.3' 12.6 1.3' 12.6 1.3' 2009 April 29
65P/Gunn Virgo 12.7 1.2' 12.7 1.1' 12.7 1.1' 2009 June 21
88P/Howell Virgo 12.8 44" 12.6 43" 12.3 42" 2009 June 21
C/2007 N3 (Lulin) Gemini 12.9 1.2' 13.2 1.1' 13.5 1.1' 2009 May 17
C/2006 OF2 (Broughton) Cancer 13.1 55" 13.3 53" 13.5 51" 2009 May 27
P/2009 L2 (Yang-Gao) Serpens Cauda 13.2 56" 13.8 46" 14.6 36" 2009 June 21
217P/LINEAR Aquarius 13.3 45" 12.7 53" 12.1 1.0' 2009 June 21
C/2006 Q1 (McNaught) Corona Borealis 13.8 30" 14.0 29" 14.3 27" 2009 June 1
C/2005 L3 (McNaught) Canes Venatici 14.1 33" 14.2 32" 14.3 30" 2009 June 21
77P/Longmore Virgo 14.7 20" 14.9 19" 15.0 17" 2009 June 12
211P/Hill Cancer 14.8 33" 14.9 32" 15.0 32" 2009 May 27

*In solar conjunction and not visible

For the latest news and comet observations see the ICQ/CBAT/MPC: Recent Comet Magnitude Estimates page.  The Astronomical Headlines page of the IAU is also a good source of information, particularly for recent discoveries.

For general information about comets see Gary W. Kronk's Cometography 

Join the Comet Chasing discussion group 

Further reading: see Comet Chasing, Sky & Telescope, April 2005, pg. 83.

Make your own custom charts for your location and telescope/binoculars: software for comet observing
 

Links
Skyhound's Guide to Comets
Skyhound's Guide to Finding Comets
BAA Comet Section
Astronomical Headlines (IAU)
Cometography