(meteorobs) Observation 27-28 July 2004

[Wesley Stone]

My SDA rates on July 27 and 28 (UT) seemed consistent with my 2001 and 2003 observations. Hourly rates from my 42.6° N location were 5 and 7 respectively on those two dates this year.  When you've got a shower that's producing single-digit rates from your location, it's really easy to catch an off hour or two.  I can only conclude that that's what happened on July 29 when I only saw 1 SDA in an hour but Pierre Martin reported higher activity.  Last year on July 27, I observed 8 SDAs in my first hour and 3 in my second hour of observations.  If I'd just seen the first hour, I would have concluded that rates were decent. If I'd just seen the second hour, I would have called them poor.  It would be nice to observe for 5 hours straight to get a bigger sample size, but that's a luxury reserved for more southern viewers who have the radiant in a better location.

As for shower association without plotting, I feel confident in doing it most nights with the aid of a plotting cord (aka shoestring).  Obviously, I feel more confident the more meteors a shower is producing, as that lessens the impact of ambiguous associations or poorly-seen meteors on the rates.  

Near the Perseid max, it depends on the conditions, radiant heights and which direction I'm facing.  I generally just concentrate on the Perseids, though. As a counter, I'm most interested in rates and brightness profiles of major showers.  

--
Wes Stone
Chiloquin, OR
http://skytour.homestead.com


----- Original Message -----
From: Geert Barentsen <geert.barentsen at pandora.be>
Date: Thu, 29 Jul 2004 22:35:21 +0200
To: Global Meteor Observing Forum <meteorobs at meteorobs.org>
Subject: Re: (meteorobs) Observation 27-28 July 2004

> Hello Lew,
> 
> The radiant doesn't get higher than 20°/25° here, and the limiting 
> magnitude is pretty bad (5.2 to 5.7 in zenith)... This makes the total ZHR 
> correction factor easily bigger than 10, so you could consider my 3 SDA's 
> to be pretty impressive ;-)  Of course, it doesn't make sense to derive a 
> ZHR from a single observation, but I think the big correction factor 
> indicates that one should not derive too many conclusions from 
> high-latitude aquarid observations...
> 
> Moreover, I find it very-very-very hard to perform a perfect radiant 
> association, because it requires very-very-very accurate plots... It is 
> easy to detect a Capricornid because of it's brightness and slow speed, but 
> meteors from the aquarid-radiants or antihelion-source all seem to have 
> similar speeds (and are usually rather dim).
> In the weeks around the Perseid maximum, I report possible aquarid members 
> as "Diverse", because I do not feel able to perform a decent shower 
> association without plotting. I'd love to hear the opinion of other 
> meteorobs-members about this?? (Related question: do you follow the IMO 
> shower list during the Perseid maximum, or do you use "Perseid / 
> Non-Perseid"? I could personally do well without the latter option in 
> recent years.)
> 
> The third issue of WGN arrived in my mailbox this morning, and contained 
> two articles about the Aquarid-Capricornid complex!  Rainer Arlt and 
> Audrius Dubietis analysed this complex based on visual observations between 
> 1997 and 2002. They obtained nice results! A very interesting read!! There 
> is also an article by Robert about the antihelion source.
> 
> Greetings,
> Geert
> 
> 
> 
> 
> At 20:26 29-7-2004, you wrote:
> >Wow, Daniel, Geert, Van - none of you saw significant
> >activity from the SDAs! Were they just unusually weak
> >this year? Or perhaps observers from lower latitudes
> >(Daniel was at 49N, Geert and Van way up at 51N!) saw
> >some higher numbers from this more southerly shower?
> >
> >Did anyone below, say, latitude 35N record some more
> >interesting SDA activity during the peak period?
> >
> >Clear skies!
> >Lew
> >
-- 
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