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(meteorobs) eta Aquarids
Hi All
This is my Casual report and comment on the eta Aquarids this year.
This was my 6th eta Aquarid's shower i have observed since the first ( and
most spectacular in my opinion), which three of us observed on the local
morning of the 5th of may 1997.
And i would have to say this 2003 shower is the most disappointing one we
have seen so far.
On the night of 4/5 may/2003 we arrived at a dark site at 11:30 PM sunday
and stayed till 5:30 AM monday morning local time (14:30 - 20:30 may 4th UT)
We primarily were there to do guided widefield film astrophotography in a
tag team effort (two present). The sky was totally cloudless and we had
reasonably good seeing < about a 6.5 - 7 out of ten for transparency, and a
zenith LM in the low sixes> (there was some dust in the higher atmosphere
as a result of the continuing drought like conditions we have experienced in
recent times, giving the skies a slightly greyish colour).
While one of us was busy guiding a shot the other would watch for meteors.
We estimate we saw about 15 ETA's overall for that entire period of 6 hours.
We did see the usual amount of sporadics and three or four brilliant long
smoky sagittarids burst out from zenith.
Most of the bright lengthy Eta's that left smoke trains were between
midnight and 2 am and a few of them cut a swathe through the milky way
heading west.
The second night of 5/6 may 2003 was similar to the first night (but in fact
the eta's were of a better quality on the first night). We were there on the
tuesday morning from 2:30 am till 6:30 am local time.
We have a rough count of about 20 ETA's for this four hour period!
The LM at Zenith was dancing between 6.3 - 6.5, and transparency was about 7
out of ten.
The beautiful but deadly planet Venus, was a Pain in the A** both mornings
as it was a major cause of light pollution from about 4:30 am onwards.
Dear Reader please only read on if you are blessed with too much free time..
:)
I would like to now juxtapose this with my/our (from our memory as there is
no paperwork for this one) of the first ETA's shower we ever observed (and
our first deliberately observed shower full stop).
We drove to our usual dark site on the eastern side of the Mount Lofty
ranges and from memory it was nearly raining/or actually was, but
nonetheless heavily clouded out and very foggy - we were at about 400 mtrs
altitude .
So we decided to abandon the session, but on the early part of the drive
home noticed big holes forming in the low and heavy cloud cover . So we
decided to stop and have another go. After turning up a dirt side road we
got out and each of us found a spot and reclined on the sodden turf, warm
and dry in our new ski suits.
We watched in awe as a spookily well placed hole in the cloud exposed all of
the constellation, and about 10 degrees in extension of that ( cloud covered
about 45% - 65% of the sky most of the time with small holes forming
elsewhere occasionally as well) and stayed there. We also saw the odd very
bright one through thinner clouds.
We saw many fine & classy meteors from then on getting a count of a literal
32 in one hour, which we were satisfied with, as of course that adds up to
the 60 ZHR we expected from the predictions (taking into account the cloud
cover).
The remarkable part of the ETA shower in '97 was the proximity to the
radiant most the meteors originated from.
The most spectacular ones being a perfectly simultaneous multiple of four
that derived from the tightest seamless radiant possible (there was no gap
in the point of origin at all- they were all joined as one - at the hip so
to speak). They were of totally equal length - about 10 degrees - and of the
same exact magnitude (about +2). All four had the same golden white
appearance and slight nanosecond train, and were very fast and slender. In
fact they were literally identical.
They also at perfect right angles to each other and formed a perfectly
symmetrical + shape ( i.e. quadrants - points of the compass) and were at
the perfect angle to our position so a to be standing upright, not unlike a
cross.
The way those four ETA's demonstrated to me the principle of the radiant and
how it works, at the time of viewing, was transcendental in nature for me. I
was hooked that from that moment on.
*None of our group or myself have never seen anything like this perfect
compass point set of meteors in the six years since or prior to this
shower-either accidentally or while observing showers and other events from
dark sites and darkish outersuburbs.
We have seen mirror sets of twos and threes from a radiant of mighty leonid
fieballs even, but nothing has impressed me more than that sublime quartet
in '97* (this sight may be common to some on this list, with their
favourable positions for the major showers - i apologise if i seem awestruck
or worse!.)
But i digress. On arrival back at a members residence in his north eastern
foothill suburb of Adelaide, after viewing this '97 ETA shower, we were
treated to the most magical (exaggerated Ponzo illusion) picture sharp,
gigantic, bluest Earthshine Moon rise, over the Adelaide hills (the sky was
clear back in Adelaide), i have ever seen.
While watching this, and the radiant, in awe in the most beautiful light
blue twilight of the impending sunrise. Suddenly appeared two massive,
daylight, thick profuse, heavily smoking , ETA's storming across the sky
heading west from near the radiant (which i could still figure out
approaching Zenith). Their wide 1.5 - 2 sec smoke trains entirely lit up by
the sun, at that altitude.
They may have about mag - 5 to -10.
Stewart and Richard then saw another similar spectacular daylight ETA
fireball within minutes of the the pair i saw.
Now thats what i call a eta Aquirid shower!
I put this shower in my top three all showers/storm i have experienced,
alongside the '98 and '01 leonids!
In the years since then there has been other great ETA showers.
1998 may 5 - cant find our written records, but good memories of hitting the
predicted ZHR of 60
1999 may 6 - watched on my own from normally semi-dark eastern foot hills
backyard and getting a good show (i also did days either side of shower
peaks commonly, but have no records as i was usually on my own.)
I remember getting a literal 30 ZHR for the peak hour, including many
nice meteors, despite a huge bright waning gibbous moon being only around 20
or so degrees away from the radiant!
2000 may 5 - three of us watched it from near the usual dark site - slightly
obstructed views due to trees.
have written records of group count:
3:30 - 4:00 am 15 ETA's
4:00 - 5:00 am 46 ETA's
5:00 - 6:00 am 65 ETA's
and have a best literal hour of
5:20 - 6:20 am 75 ETA's
And many of these on this morning were of an entertaining nature.
2001 may 5 - Full Moon. observed from same backyard setting - got predicted
60 ZHR- after allowing for the moon.
2002 may 5 - first *sub* predicted ZHR ETA shower for us - even after
allowing for the LQ moon interference - at around a third the rate expected,
and being also mostly faint meteors.
2003 - nasty
2004 - ???
Kind Regards
Kearn Jones
Adelaide, Australia
35 south 138 east
So-X Obs
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