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(meteorobs) Fwd: Possible early Perseids? (Pierre Martin)

-- [ From: Robert Lunsford * EMC.Ver #2.5.3 ] --

Thanks Norman for your last post. Very interesting information on
Perseids and eye perceptions. I'd like to continue the Perseid topic
with...


Possible early Perseid meteor activity ?
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The IMO officially states the Perseids with an activity occuring from
July 17 to August 24. I have noticed in past ALPO Yearly summaries,
Perseids observations from other observers on dates much earlier than
this. The early July Perseid activity seems to be somewhat variable. In
the final days of July, activity picks up slowly and gradually until it
peaks on August 12.

By going back into my own observations from 1995 to 1997, I have
observed early Perseids myself. My earliest reported Perseids last year
were 2 seen on July 5/6. I have determined their identity by projecting
the theoretical radiant to this date. Radiant in question would be
positioned roughly 23:50 +50d (border of Cassiopeia, Lacerta and
Andromeda)  Careful use of velocity and path lenght were taken into
account to reduce the chance of pure alignment with sporadic pollution.
On that date, my activity seen was very low/barely detectable. I know
there is good chance for sporadic alignment with 1 or less suspected
Perseid per hour. Despite this low number, the few meteors I have seen
coming from the projected radiant had very similar caracteristics to the
Perseids; classic fast, thick trained and long path meteors. Around July
23, my Perseid rates were at least at the sporadic background and
appeared higher than the official quoted rate of 1 per hour for that
date.

As an experiment last year, I tried to project the Perseid radiant well
into September. I did see meteors align, but I had no problem saying
they were sporadic or other minor showers. Either path lenght, velocity
or distance did not match or at least made it very unlikely. I have
reported my latest Perseid ever on August 29/30. In contrast, my meteors
reported in early July all seemed to pass every test.

I would definitely try to observe the possible meteors in early July,
especially before the moon starts to interfere once again. I think that
very careful plotting of any candidates could be very useful to
determine a radiant. (if one indeed exist).

Recently, I have been discussing the issue of early Perseids with other
observers. It seems likely that real Perseids cannot start producing
this early in July. There might be a different radiant or sub-radiant
occuring with meteors similar to Perseids but not at all related. This
would in turn explain why the reported July activity jumps up and down.
It is to be noted that the well known July Pegasids are active between
the 7 to 13 and peak on July 11. They are also very fast and might
easily be confused with possible Perseids. Last year, I was careful not
to include these members in my list of possible candidates.

Any observer at higher latitudes will be much better positioned to catch
this possible activity since the radiant will be climbing higher in the
sky sooner in the night. After July 7, the moon may become too bright
for useful observations. These meteors, however do tend to be bright and
easily recognizable.

If anyone feel they have additional information they'd like to share on
this topic, I'd appreciate that.

Here below is a list of dates with the activity of my own early reported
Perseids in July for the years between 1995-97. All are from my usual
location near Ottawa, Ontario, CAN. Clear sky unless noted.

1995
----
July 21/22 (LM=5.5) 10% cloud 12:48-1:25 EDT - 1 PER
     23/24 (LM=5.8) 10% cloud 12:57-1:25 EDT - 1 PER
     24/25 (LM=5.8)           11:51-3:22 EDT - 6 PER
     27/28 (LM=5.9)           12:24-4:32 EDT - 9 PER
     29/30 (LM=5.8)           12:04-3:56 EDT - 7 PER
     30/31 (LM=5.9)           11:14-4:08 EDT - 22 PER

1996
----
     10/11 (LM=5.8)           3:03-8:02 UT - 5 PER
     15/16 (LM=5.7)           6:23-8:04 UT - 1 PER
     16/17 (LM=5.9)           3:22-8:17 UT - 8 PER
     17/18 (LM=5.7)           3:27-8:16 UT - 6 PER
     19/20 (LM=5.9)           4:33-8:00 UT - 8 PER
     20/21 (LM=6.0)           4:10-7:46 UT - 8 PER
     21/22 (LM=6.0)           3:08-7:26 UT - 10 PER
     22/23 (LM=5.9)           3:41-6:49 UT - 3 PER
     23/24 (LM=5.7)           4:35-8:10 UT - 7 PER
     27/28 (LM=5.3) 5% cloud  6:42-8:23 UT - 4 PER

1997
----
     5/6 (LM=6.0)           5:18-7:40 UT - 2 PER
     7/8 (LM=6.1) 5% cloud  5:13-7:30 UT - 8 PER
     9/10 (LM=6.0)          4:06-7:45 UT - 3 PER
    10/11 (LM=6.2)          4:30-8:00 UT - 5 PER
    12/13 (LM=5.9)          5:11-6:35 UT - 3 PER
    28/29 (LM=6.0)          3:06-6:15 UT - 11 PER
    29/30 (LM=6.1)          3:38-7:00 UT - 18 PER
    30/31 (LM=6.0)          4:06-6:25 UT - 6 PER
    30/31 (change in location)  7:29-8:00 UT - 4 PER

Pierre Martin                                             .  .      .
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Ottawa, Ontario, CAN                              / /   .     .  .   .  
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Visual meteor observer                          // /       / . .    .  
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Ottawa Astro Observers Group                    / /   .   *      .   .
Graphic Designer (National Aviation Museum)   =/ / |\      .       .    
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