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RE: (meteorobs) Observing the Arietids-Triangulids
I'm going to add my two-cents worth.
One of the key features initially noted about the "Aries-Triangulid" stream by
Gliba and myself in 1993 was that most of the meteors were not extremely
bright, usually in the 3rd to 4th magnitude range. In fact, and bear with me
here as I don't have my notes on this stream handy, but I think both Gliba and
myself may have even seen a couple of 5th magnitude meteors as well.
An addition to the above. My search through the radio-meteors of Zdenek
Sekanina's two 1960s Harvard surveys reveals over 40 radio meteors from this
stream. Sekanina did spot the "Alpha Triangulids" in 1969, but there were also
members in his earlier 1961-1965 survey. Grouping them altogether produces the
"over 40 meteors" I already mentioned and this is a rather large sample from
that project. This caused me to suspect that greater activity might be present
to telescopic observers.
One more point to all of the above. Malcolm Currie, a long-time telescopic
meteor observer from England, detected a rather large number of telescopic
meteors from the "Aries-Triangulum" region in 1994.
The above evidence would seem to imply that the overall population of this
stream must be composed of small particles. Certainly much smaller than we see
in well-known streams like the Perseids. This brings forth a very important
point which could affect visual observations.
The further a meteor is from its radiant, the greater will be its APPARENT
speed. If a meteor's size enables it to remain at a maximum magnitude of, let's
say, 4 for 1 second, when would it be most noticeable? I believe faint meteors
would be most noticeable a short distance from the radiant when its overall
length is about 10 degrees, rather that when relatively far from the radiant
when its overall length might be 40 or more degrees. I had a serious eye injury
last summer (which I fortunately made a nearly complete recovery) and learned a
lot talking to the doctor during my visits over a period of three months.
We all know that cameras work similar to our eyes. Photographic film grains can
be loosely compared to the cones in the back of the eye. Anyone who has taken a
time exposure of the sky hoping to photograph a meteor (Bob Lunsford!!!) will
know that a fast bright meteor has less of a chance of registering on the film
than a slow bright meteor. Part of what makes the meteor leave an "impression"
on the film is how long its light is projected on each grain on the film. Along
the same lines, the cones in the eye are relying on an "impression" of light to
let the brain know that something is there. A faint short-trailed meteor has
more of a chance of being seen than a faint long-trailed meteor, unless you are
lucky enough to be looking at the right place at the right time.
What all of this boils down to is that I believe it would be advantageous for
observers to look toward the region of Aries and Triangulum when looking for
meteors during the first half of September for the following reasons:
--First, you have a better chance of seeing the generally faint meteors from
the suspected radiant.
--Second, Bob Lunsford is right in saying that by observing 30 to 40 degrees
from the radiant you might see only about 25 percent of the potential meteors.
We do not know what the actual visual hourly rate is, but if it is only 4 (for
example) you could only see one possible meteor. Because of the region you are
looking, this would be a long-trailed meteor. Depending on the observer's
plotting accuracy, this plot might not be very valuable in establishing the
radiant of the stream. In addition, an observer would have to put in more hours
than someone looking at the radiant in order to detect enough meteors to
establish whether the radiant is even real or not.
--Finally, (continuing with the plotting concern noted in the second point
above) short-trailed meteors can more accurately point to the radiant and since
there is still some uncertainty whether the radiant is in Aries or Triangulum
this would be nice. I would personally like to call this stream by a normal
name rather than the "Aries-Triangulids." :-)
That's about it for now!
Gary