Many predictions for this year's LEONIDS have been made by several very competent astronomers, but just the number of predictions and their sometimes being somewhat contradictory has become somewhat confusing. Three groups or individuals are now predicting the higher peak over the US, but the trail seems to be behaving a bit oddly. The fourth group, which made the most accurate predictions so far, but also failed for the 4-rev trail, predicts it to be the less strong of the two storms.
Anyway, these are the current predictions.
(this summary by Jure Atanackov):
"1. Asher & McNaught: I think these haven't been revised recently with the new data from 2001 Leonids. I don't know how accurate the ZHR figures are.
Nov 19. 03:53UT 7-rev 3000
Nov 19. 10:29UT 4-rev 10000
"2. Lyytinen and van Flandern: these have been revised very recently, as most of you are probably aware of. In their research they have found that the 4-rev trail seems to be 'underpowered', judging by the less than expected activity levels during the 2000 and 2001 caused by this trail. Their current predictions for the 4-rev trail take into account this effect, and Esko comments that if the 'underpowered' scenario should turn out untrue, the ZHR could be up to 40% higher. I'm not sure about the 5-rev peak strength.
Nov 19. 04:02UT 7-rev 3500
Nov 19. 06:45UT 5-rev 160?
Nov 19. 10:44UT 4-rev 2600
They seem to have predicted the strength of the 7-rev peak in 2001 very well. Just a couple of days before the outburst, Esko made (don't know if he published) a prediction for ZHR 1800. Which is very close to the current ~1600 level from IMO global analysis. Therefore, I am, personally, fairly confident in their 7-rev peak prediction.
"3.Jenniskens: his predictions for the last year's peak seemed off at first, especially the 7-rev peak, where his predicted ZHR of 4200 was way off and also the timing was off by more than half an hour. He explains the error on Leonid MAC website: 'The 1767 dust trail (seen over the USA) was not at the expected position, due to an encounter with Earth in a prior return. Because of this, the lower than anticipated peak rates over the USA (factor of 2) and later than expected peak time (40 minutes) will not affect predictions for the 2002 encounter, according to Jenniskens'. But he did get the strength and duration of the combined 4- and 9-rev peaks with predicted ZHR 3600 and a longer total duration than the 7-rev peak. These are his new predictions:
Nov 19. 03:58UT 7-rev 4000 +/- 1000
Nov 19. 06:22UT 5-rev 40?
Nov 19. 10:36UT 4-rev 5000 +/- 2000
"4. Langbroek: Marco also made some predictions or estimates about this year's activity, he also posted them here on 'meteorobs' saying:
- - 7 revs trail ZHR 2500 minimum to 7100 maximum
- - 4 revs trail ZHR 3000 minimum to 6500 maximum
....with chances best that the minimum figures are the ones to go for, he suggests, especially for the 7 rev trail."
Note - while there will no doubt be changes in the predictions between now and mid-November, it is doubtful that they will change substantially. And these should certainly be close enough for you to get ready for the shower (and probable storm), possibly the last really big display for many years.
For still more, see the Web site of Robert McNaught,
The Web site of David Asher,
and, as we get closer to the Leonids, the Cosmic Mirror of Daniel Fisher.
What about the possibility of extreme DX via the Leonids? One of two things would be required (in addition to a very high rate): Either large particles, producing a large amount of ionization (because of the loss involved in double-hop), or ionization at an extreme altitude.
During the 1998 and 1999 Leonids, Dr. Noah Brosch and his team claimed to have observed a population of Leonids at twice the expected burn altitude. However, there were no reports of extra-long-distance signals, and many feel that this was an artifact of the radar system. (If you have information on any contacts beyond 2500 km, please let us know, as Dr. Brosch has made an appeal for any reports). For more, see Dr. Brosch's abstract, and be sure to follow the links.
Interestingly, it was felt that the "fireball storm" of 1999, even though it had a lower rate, produced better MS conditions than did the much higher rates (but with smaller particles) of the next few years.
Is extreme DX possible during the Leonids this year? Nobody knows. It would be difficult. But it is certainly unlikely unless someone tries! Note the expected peak times (above), use OH5IY's MS-Soft program to determine the most suitable direction, and set WSJT to save everything received during your DX schedules. This may be the last year for a Leonids storm in our lifetimes.