C/2001 Q4 NEAT
The Great Binocular Comet of 2004 no1
Closest to Earth on 6 May 2004 at 0.32AU
Closest to Sun on 16 May 2004 at 0.96AU
Maximum magnitude 2.8 in early May 2004
C/2001 Q4 NEAT was discovered on August 21st 2001 by the Near Earth Asteroid
at an enormous distance of 10 AU from the Sun (1AU=Earth-Sun distance).
This comet was predominantly a Southern Hemisphere object until May 2004.
Closest approach to the Earth occurred on May 6th 2004 at 0.32 AU (48 million kms).
At this time, the comet peaked at about magnitude 2.8 and was prominently visible
high in the evening sky for Southern Hemisphere observers in the constellation of Puppis.
Closest approach to the Sun occurred on May 15th 2004 at 0.96 AU (144 million kms)
when the comet was situated in Cancer, very close to the beehive cluster M44.
Southern hemisphere observers had a treat from May 18th, when comet C/2002 T7 LINEAR joined
comet NEAT in the evening sky, and both comets were simultaneously observable with the unaided eye.
See below a light curve based on my personal observations.
The red curve displays the predicted magnitude from its discovery brightness in 2001. Ho=3.5, n=4
The orange curve is my observed light curve. Ho=5.3, n=3
You can see that the brightness fell short of prediction by nearly 2 magnitudes.
This appears to be NEAT's first and only passage through the inner solar system.
New comets (non periodic) tend to fall below expectations
CCD images on Oct 15th, Dec 27th 2003, Jan 23rd, March 12th 2004 showing development.
C/2001 Q4 NEAT. Taken on 2004 April 17 at 12:28 UT.
10x30 second exposures through a 135mm Hannimex lens at f/5.6 piggybacked on a C11.
Field of View 2x2.5 degrees. Note the short broad dust tail and the long thin ion tail.
Coma size is 12 arcminutes in diameter which translates to 350,000kms across.
Note galaxy NGC 1313 at top right of field.
2004 April 20 at 11:05 UT.
30x30 second exposures through a 135mm Hannimex lens at f/5.6.
Field of View 1.8x1.5 degrees. The comet appears edge-on to the Earth.
2004 April 20 at 10:40UT. 30x30second exposures taken through a Celestron C11.
Flat fielded and gauss equalised to draw out details around the nucleus.
Right: Same photo with the Larsen-Sekania filter applied. This enhances the jets and shells around the nucleus.
2004 April 21 at 10:15UT. Left: 27x20second exposures through Celestron C11. Right: Same photo with the Larsen-Sekania filter applied.
2004 April 26 at 11:20UT. 25x20second exposures, flat fielded
2004 May 4 at 10:32UT. Left: 30x10 second exposures. Right: Larsen-Sekania filter applied
2004 May 6 at 11:50UT. Left: 13x15 sec exposures through C11 at f/3.3. Right: Larsen-Sekania filter applied.
2004 May 7 at 11:10UT. Left: 15x15 sec exposures through C11 at f/3.3. Right: Larsen-Sekania filter applied.
2004 May 7 at 10:20UT. 10x30 second exposures. Field of view 2 degrees wide.
Note star clusters M47 (middle) and M48 (right) in the field of view.
2004 May 8 at 09:30UT. 10x30second exposures. above. The bright star to the left of the comet is Alpha Monocerotis.
below is a 30x30second exposures stacked on the comet and unsharp masked to draw out structure in the tail.