SPACE.com asked a leader from each forecast group how he thought their work stacked up against the others this year. Below are the replies, edited for brevity and clarity.
[ZHR = peak hourly rate; UT=Universal Time; rev.=revolution (7 rev. means 7 orbits ago for comet Tempel-Tuttle, which leaves a new trail of debris every 33.2 years. These revolutions are also discussed as the year in which they occurred, as in "1699" being a dust trail left in that year.)]
David Asher (of Armagh Observatory with Rob McNaught):
I haven't had time to assess this. At present my complete guess is that Lyytinen et al. may be the 'winners' but that models that followed the 'dust trail technique' pioneered by Reznikov et al. were all broadly correct, as Rob McNaught and I (among others) were 100 percent sure they would be, even though we didn't know which would be the 'winning' model among them.
The shower was further confirmation that meteor storm prediction is essentially solved, albeit many people should be able to do exciting new research to try to refine the details.
Esko Lyytinen (with Markku Nissinen, Tom Van Flandern):
According to early data, the rates, especially at the Pacific area, seem to be a little below the predicted. The times predicted were quite good, at least enough for choosing the observing location.
What is especially interesting is the timing of the 7 rev. outburst (visible in Americas). Our last modeling with nongravitational effects put it about half-an-hour later than the previous simple trail models. This seems to be about the observed (it may have occurred even a bit later). I think that this gives quite strong support to our model. Even beforehand I was very interested to see the timing of this outburst peak.
Peter Jenniskens (of NASA's Ames Research Center):
Our peak rate from FISTA was about ZHR = 1200/hr peaking at 10:40 UT, while our ground station at Mt. Lemmon had about 1500/hr. They also recorded a narrow spike up to 2600/hr around 11 UT, the cause of which is not clear yet. My personal estimate from the ground was around 1500/hr. Peak ZHR from our ground station in Australia was about 1900/hr at about 18:15 UT (1866 peak). A modeling would be needed to determine the peak rate and time of the 1699 peak.
It is clear that a comparison of the video records is needed to make sure these numbers are well calibrated. If true, they definitely would support my prediction that the 1767 dust trail was closer to Earth's orbit and the 1866 dust trail further away than earlier predictions by Asher and McNaught as well as Lyytinen.
Esko Lyytinen's model did good regarding the peak times, especially where it concerns more subtle effects from gravitational perturbations on the shape of the dust trail near Earth's orbit. Observations have surpassed the sophistication of the model by Asher and McNaught. Brown and Cook are wrong.
Bill Cooke (of NASA's Marshall Space Flight Center, with Peter Brown):
If we judge the accuracy of the forecasts from the very preliminary numbers we have now using the criteria of intensity and timing, then I can state the following:
FIRST PEAK:
Intensity
- Asher/McNaught called it to within 20 percent or so
- Brown/Cooke also had it right to within 20 percent
- Lyytinen/Van Flandern factor of 2 too high
- Jenniskens factor of 4 too high.
Timing
- Asher/McNaught off by about 30-40 minutes (too early)
- Brown/Cooke no peak at this time
- Lyytinen /Van Flandern - off by about 30-40 minutes (too early)
- Jenniskens - off by about 30-40 minutes (too early)
The 1799 peak predicted by Brown/Cooke apparently did not materialize, but it has been suggested that the error in the timing of the first peak was due to influence from 1799 material, which was not a significant influence in forecasts other than Brown/Cooke.
SECOND PEAK:
Intensity
- Asher/McNaught , Lyytinen/Van Flandern 2.5 times too high
- Brown/Cooke more than a factor of 3 too low
- Jenniskens too high by 33 percent
Timing
- Asher/McNaught, Lyytinen/Van Flandern just slightly early
- Brown/Cooke about 30 minutes early
- Jenniskens about 30 minutes early
[Cook continues:]
This is the way things look now. However, these numbers are very preliminary and are almost certain to change (The IMO revised their 1999 numbers at least 3 times, and that was for only one peak).
Another item of interest is that the data we collected on the night of the 17th may show a small peak from 1932 and 1965 trails; this was not predicted in any forecast.
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