(meteorobs) Meteor Observation 13/11/2009

Fri Nov 20 11:16:17 EST 2009

Hello,

First of all I'm very glad that you, Daniel, returned to meteorobs.
I've not seen your letters for some time.

On Leonids 2009 I can say that there are some discrepancies between
predicted maximum and observed one. Observations showed that peak
activity was a way below expectations (expected ZHR ~150-200 vs
observed ZHR ~120-130, though perhaps it is still a preliminary
value). Also, observed maximum time is ~1 hour earlier than predicted
one.
Some other minor maxima seem to not have appeared in observing data,
for example, enhancement from 1767 trail at 13:30 UT 16 November,
though amount of observing data is to small to make reliable
conclusions.
On other hand the maximum turned to be broad and seem to have a number of
submaximas, which is in good accordance with predictions.
Also, expected moderate activity from 1567 trail seem to have appeared, giving
a plato with ZHR of 25-35 starting from ~7 UT 17 November and up to
main outburst.

Despite those discrepancies I think predictions for Leonids 2009 (as
well as for 2008) were a success, as we speak of old trails (1466,
1533 and 1567). Let's don't forget that last perihelion of the comet
55P was in 1998, 11 yeas ago. And as far as I know, there are no reliable
historic accounts on high Leonid activity in a year such far in time from
perihelia of the Leonid parent comet. So far before 17 November 2008 the very
possibility of strong Leonid activity from so old trails looked very obscure.

Best regards, Mikhail

DG> Hi,

DG> the weekend before the predicted maximum skies were fairly clear from my 
DG> observing site near Stuttgart ... so I went out to observe, which was 
DG> certainly worthwile even though only one Leonid showed up (as one would 
DG> expect due to the rather low radiant). See the attached report (which has 
DG> also been submitted to IMO via the web form).
DG> I would be very interested in hearing some expert opinions on how well the 
DG> preliminary results fit with the various predictions!

DG> Anyhow, clear skies to all

DG> Daniel

DG> ------

DG> Day: 13      Month: 11    Year: 2009
DG> Begin:23:00 UT          End:23:54
DG> Location  long. E9d26'25"  latit. N48d51'57"

DG> Site: Winnenden-Birkmannsweiler, near Stuttgart
DG> Country: Germany

DG> Observer: Daniel GRUEN   IMO code: GRUDA
DG> Any questions? Mail me (daniel_gruen at web.de)

DG> Showers:
DG>  ------------------------
DG> | Shw.|alpha|delta|veloc.|
DG> |------------------------|
DG> | AND | 023d| +33d|19km/s|
DG> | OER | 060d| -02d|27km/s|
DG> | NTA | 061d| +23d|29km/s|
DG> | STA | 062d| +15d|29km/s|
DG> | NOO | 083d| +16d|44km/s|
DG> | AMO | 112d| +02d|65km/s|
DG> | LEO | 152d| +23d|70km/s|
DG> | SPO | --- | --- | ---- |
DG>  ------------------------
DG> these figures are taken from the current
DG> AMS Meteor Activity Outlook by Robert Lunsford
DG> * average radiant height (est.)
DG> + Antihelion source for not shower-attributed antihelion meteors

DG> Periods:
DG>  -----------------------------------------------------
DG> | Period    |Field    |Teff| F  | lm |LEO|NTA|STA|SPO|
DG> |  (UT)     |RA   Dec |  h |    | m  |M|N|M|N|M|N|M|N|
DG> |----------------------------------------------------|
DG> |23:00-23:54|120d|+62d|0.80|1.00|5.10|P|1|P|1|P|1|P|5|
DG>  ----------------------------------------------------

DG> Magnitude Distribution:
DG>  ---------------------------------------------------------
DG> |Shower | -4| -3| -2| -1|+-0| +1| +2| +3| +4| +5|avg.| tot|
DG> |-------|---|---|---|---|---|---|---|---|---|---|----|----|
DG> | LEO   | - | - | - | - | - | - |1.0| - | - | - |2.00|   1|
DG> | NTA   | - | - | - | - | - |1.0| - | - | - | - |1.00|   1|
DG> | STA   | - | - | - | - | - | - | - | - |1.0| - |4.00|   1|
DG> | SPO   | - | - | - | - | - |1.0|1.0|2.5|0.5| - |1.90|   5|
DG>  ---------------------------------------------------------

DG> Train Distribution:
DG>  ------------------------------------
DG> |dur.| 5s| 4s| 3s| 2s| 1s| <*| no|tot|
DG> |----|---|---|---|---|---|---|---|---|
DG> |LEO | - | - |1.0| - | - | - | - |  1|
DG> |NTA | - | - | - | - | - | - |1.0|  1|
DG> |STA | - | - | - | - | - | - |1.0|  1|
DG> |SPO | - | - | - |1.0| - |1.0|3.0|  5|
DG>  ------------------------------------
DG> * these trains persisted only for a few tenth of a second

DG> Meteor Data:
DG>  --------------------------------------------------------
DG> | No| Time| Mag|Vel|Shw|Train|XBeg|YBeg|XEnd|YEnd|Map|Acc|
DG> |---|-----|----|---|---|-----|----|----|----|----|---|---|
DG> | 01|23:07| 3.0|4.0|SPO| --- | 052| 244| 051| 204| 4 | 2 |
DG> | 02|23:09| 2.5|1.5|SPO| <1s | 140| 222| 123| 232| 4 | 2 |*
DG> | 03|23:12| 2.5|2.0|SPO| --- | 104| 250| 136| 229| 7 | 3 |
DG> | 04|23:17| 2.0|2.5|LEO| 3.0s| 219| 119| 301| 208| 2 | 2 |+
DG> | 05|23:21| 1.0|2.0|NTA| --- | 194| 266| 180| 274| 4 | 3 |
DG> | 06|23:26| 4.0|2.0|STA| --- | 083| 231| 043| 237| 4 | 2 |
DG> | 07|23:48| 1.0|2.0|SPO| 2.0s| 070| 206| 080| 208| 4 | 2 |
DG> | 08|23:49| 3.5|5.0|SPO| --- | 131| 276| 201| 317| 4 | 2 |
DG>  --------------------------------------------------------
DG> enumeration starts in the 13/11/2009 session
DG> all coordinates in mm from the lower left corner of the map
DG> velocity scale:
DG> 1 - very slow; 2 - slow; 3 - medium; 4 - fast; 5 - very fast
DG> * this slow and rather short meteor aligns well with both the 
DG>   NOO radiant (to which it was closer) and the OER radiant
DG>   (for which at the larger distance the slow speed still fits)
DG> + this meteor count was supported by and is dedicated to
DG>   A. Silva

DG> Comments:
DG> Quite nice activity in this fairly mild November night. 
DG> Apart from the spurious Sporadic at 23:09, which might be
DG> from either of two rare showers, the earth-grazing Leonid
DG> at 23:17 was a real highlight. Clear skies to all planning
DG> to observe the predicted maxima this year.

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