(meteorobs) Draconids: population index & ZHR

[aac at arm.ac.uk]

Hi Geert,

Excellent work.

I hope you get some draco-boulders from LT too.

Regards,

         Tolis.

> All,
>
> Based on 2164 Draconid magnitudes reported to the IMO by visual observers,
> I
> computed a population index of:
>
> r = 2.8 +/- 0.05   (for October 8, 16h00-24h00 UT).
>
> This suggests that the Draconid outburst consisted mainly of faint
> meteors,
> as expected. The visual graph at www.imo.net has now been updated to take
> this value into account. This has the effect of raising the peak ZHR from
> ~350 (under the previous assumption of r=2.6) to ZHR ~400 (assuming r=2.8)
> near 20h00m +/- 10m UT. However, it must be made clear that absolute
> values
> for the ZHR are known to be uncertain during periods of full moon, perhaps
> by up to +/- 50%.
>
> Nevertheless, it appears that the observations match the predictions in a
> very impressive way. Congratulations to all involved!
>
> The magnitudes required to compute the population index are available in
> machine-readable format at the bottom of:
> http://www.imo.net/live/draconids2011 .
> The computation method used is described in (Arlt et al. 2003):
> http://adsabs.harvard.edu/abs/2003JIMO...31...77A
>
> Best wishes,
> Geert
>