Comet Corner

                                                   This is a periodic update on observational aspects of visible comets.

                                                                                     Sept. 4^th, 2009

             (Editorial note: Currently, the Comet Corner will only report on either the brightest or most interesting one or two comets each month)

     Comet C/2006 W3 (Christensen) is an intrinsically bright, long period comet that doesn’t make a very close approach to us. This comet reached perihelion on July 6^th at 3.12 AU. Last year it made a secondary close approach to Earth on Nov. 15^th, 2008 at 3.36 AU, but attained maximum brightness of about 8^th magnitude in August when it made even a closer approach to the Earth at 2.31 AU on Aug. 12^th. Christensen is currently about 8.5 magnitude and only slowly fading as it moves southerly in Aquila, where it will remain the rest of Sept. Christensen has well-condensed coma rendering it favorable for observing. Christensen is up all evening and most of the morning during Sept. Christensen is a great comet, and if it wasn’t so far from the Earth and Sun it would rival Hale-Bopp when it was near the Earth and the Sun.

   Comet 22P/ Kopff is a returning periodic comet with about a 6.5-year period. At perihelion, which occurred on May 25^th, it was just outside the orbit of Mars (1.57 A.U.) Years later it will return to its aphelion just outside the orbit of Jupiter (at about 5.34 AU in July 2012). Currently, Kopff is about 11th mag. and fading. It will remain fairly steady as it just had closest approach to the Earth on August 3^rd when it reached 0.77 AU. Kopff is currently moving southwesterly in Aquarius where it will remain the rest of Sept.

   Comet 88P/Howell is a returning periodic comet with about a 5.5 year orbital period. It is, currently, about 9.5 magnitude as it moves eastward in Libra, ending Sept. in Scorpius. Since perihelion isn’t until mid-Oct. it will probably become a little brighter during Sept. Howell is an early evening comet, setting at about 10:30 pm at the beginning of Sept.

Current comet magnitudes (September 3) and observable region (September 3)

·   Comet                          Magnitude   Trend   Observable    When visible

·   Christensen (2006 W3)               8.5    fade    65 N to 65 S  all night

·   Siding Spring (2007 Q3)             9      bright  Conjunction

·   88P/Howell                          9.5    bright  35 N to 80 S  evening

·   Garradd (2008 Q3)                  10      fade    Poor elongation

·   Cardinal (2008 T2)                 11      fade    25 S to 80 S  evening

·   22P/Kopff                          11      fade    50 N to 80 S  best midnight

·   217P/LINEAR                        11      fade    60 N to 75 S  morning

·   Yi-SWAN (2009 F6)                  11.5    fade    15 N to 40 S  early morning

·   116P/Wild                          12      fade    Poor elongation

·   222P/LINEAR                        12      fade    20 N to 10 N  early morning

·   STEREO (2009 G1)                   13      fade    40 S to 80 S  early morning

·   65P/Gunn                           13      steady  Poor elongation

·   29P/Schwassmann-Wachmann           13 ?    varies  Poor elongation

·   64P/Swift-Gehrels                  14      fade    35 N to 10 N  early morning

·   McNaught (2005 L3)                 14      fade    Poor elongation

·   Lulin (2007 N3)                    14      fade    50 N to 15 S  early morning