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(meteorobs) In defense of the Perseids...and myself

On Mon, 11 Nov 1996 GeoZay@aoldot com wrote:

> In a message dated 96-11-11 15:25:47 EST, you (Norman) write:
> 
> << The Dec S&T has a Perseid writeup.  I was astonished at the reports of a
>  good shower in there, people seeing 100/hr!  They used only the highest
>  counts giving the impression of a great year.  No way were the 1996 Perseids
>  great : the best I could do was only 28.  At least not great from North
>  America.  As usual there are undocumented high Perseid perceptions out there
>  that perpetuate the notion of Perseids being a "very strong and reliable"
>  shower.  Get these people out for the Geminids and they would likely see
>  200-300/hr.  That's the best of the year hands down.  Even I see 80-85/hr
>  from the Geminids routinely.

The Perseids are a strong and reliable annual shower (and there are only a
few of these).  They have a longer activity period than do the Geminids. 
Plus, for many of us in the more northern parts of the Northern
Hemisphere, they occur when the weather is most likely to be conducive to
observing (clear and fairly warm).  The Perseids have fairly high
velocities and often leave trains. The Geminids are a very rich, pretty
shower, and are favorably situated for much of the world to view. 
Whenever I complain about bad weather for the Geminids, I get e-mails from
people in the tropics bragging about watching them while wearing shorts. 
Up here, I can only hope for "severe clear" rather than "severe cloudy"
weather in mid-December.  (I've never seen more than 90/hr. at Geminid
max, but I've only had two years when it was clear and moonless, so I
can't dispute claims that the Geminids are superior to the Perseids.  If I
really believed I could see 200/hr., I'd definitely make a long trip to be
there!)

Twenty-eight Perseids sounds like a pretty low peak count, but not 
unreasonable depending on the hours observed, limiting magnitude, zenith 
distance of the radiant, luck, perception, etc.  I had fairly low Perseid 
counts in 1991 and 1993, but saw the West Coast outburst of 1994 and got 
very good rates for two days in 1996.  As always, there is a caveat that 
an individual observation (mine, yours, or anyone's) represents only a 
very small piece of a complex meteor stream.  S&T wanted individual 
reports, and those received and printed were probably biased toward the 
higher rates.

>  
>  Norman
>  
>   >>
> --------
> I agree with you here Norman. I highly suspect some of those U.S. Perseid
> Counts might also include various other showers that were active as well as a
> healthy number of sporadics. Also, that one guy in Oregon(?) must have had a
> high LM as well. 

Nobody crowed when I posted my summary reports for August 10/11 and 11/12 to 
meteorobs, and this included the same numbers quoted in the S&T article 
(broken up into periods of ~1 hour Teff).  I didn't refer to all 
non-Perseids as "sporadics" in either e-mail, but just "non-Perseids" 
with the understanding that some of these came from minor shower radiants 
that are best identified through plotting.  The Perseids were very 
active, and I focused on the Perseids for the purposes of hourly rate 
data and magnitude distributions, just as advised in my copy of the 1985 
IMO Visual Handbook.  Sporadic pollution (or "non-Perseid" pollution) is 
not entirely avoidable, but the most active minor showers during the 
Perseid max. are the Alpha Caps and various Aquarids that have radiants 
clear across the sky from the PER.  The Kappa Cygnids might be a source 
of pollution, but fortuitously aligned meteors would be rare.  

Something to consider is an observer's latitude and thus, the zenith 
distance of the radiant.  At 45N, the PER radiant culminates near the 
zenith.  As for dark skies, use them if you've got them.  My Lm hovered 
around 6.5  all night; not spectacular but better than the sites of many 
observers.  

_Sky and Telescope_ is sort of a popular astronomy magazine; the
"Observer's Notebook" just listed a few of the general impressions of
readers.  Most people who read this section of S&T aren't expecting
anything too scientific, just a rundown of what people saw and some
aesthetically pleasing comments.  In the same sense, a lot of people just 
want to see a meteor shower, so the best pieces of advice that a 
magazine can give a beginner before a shower are to go to the darkest sky 
possible, to observe for as many hours as possible, and to observe after 
midnight when rates are higher.  

We all observe for individual reasons, and devote varying amounts of time
and effort to observing.  As a jack-of-all trades amateur, I tend to be
more "up" for major shower maxima and adjacent dates; otherwise, I may be
doing CCD imaging or visual observing on the clear nights that are so
precious in Western Oregon.  Obviously, there are people on this list who 
put in an incredible number of hours plotting and photographing meteors, 
and who have loads more experience.  I am in no way questioning anyone 
else's observations, just affirming what I saw.

--
Wes Stone <wstone@lclarkdot edu>  Lewis and Clark College, Portland, OR
                 SKYTOUR Amateur Astronomy Hypertext:
          http://www.lclarkdot edu/~wstone/skytour/skytour.html
References: