(meteorobs) Eta Aquariids from Southern California

[Robert Lunsford]

I was able to view Eta Aquariid activity on three mornings this month. The
first of these, on Sunday the 4th, followed a lengthy telescopic session at
Tierra del Sol, the site of the San Diego Astronomy Association. After
telescopic observing from 2000 to 0100 PDT,  I started video recording
the activity at 0100 PDT. I then took a restless two hour nap in the bed of
my  truck and awoke at 0300 to commence visual observing. Unfortunately
the video recorder malfunctioned after 3am and all that was recorded was
the first 2 hours. There was a nearly stationary large patch of cirrostratus
hugging the northeast horizon but by looking a bit higher into the eastern
sky I was able to remove it from my field of view. For the first hour
0300-0400 PDT I was able to count 7 meteors, 4 of them were Eta Aquarids.
The first was a nice but faint earthgrazer that shot high in the
southeastern sky. The next two were slightly brighter and occurred nearly
simultaneously as they shot into the northeastern sky. The limiting
magnitude for the first hour was +6.66 with a noticeable cone of zodiacal
light apparent in the east. Toward the end of the hour I was struggling to
stay awake so I only "credited" myself with 45 minutes of actual observing
that hour.

The next hour was a waste as I could not stay awake. In the 15 minutes of
actual observing I counted 3 meteors, with 1 being an ETA. At 0500 PDT it
was too light to continue so I photographed Jupiter and packed up and headed
for home.

For the next night I viewed a bit closer from home, on the western slopes of
Mt. Laguna. The marine layer of stratus clouds blanketed the slopes all the
way up to the 3000 foot level and the sky was pitch black, one of the best I
can recall. Limiting magnitude estimates were consistently in excess of
+7.0, which is not bad for these old eyes! I started counting at 130 PDT or
830 UT. During the first hour the Antihelions were active, producing 3
meteors. I also caught an ETA at 0227, one of the earliest sightings of
these meteors. I calculated that the radiant was exactly on the horizon at
this time. A total of 12 meteors were seen during this first hour with an
average LM of +7.27. During the next hour only 2 ETA's were seen, not like
your normal maximum! 15 minutes into the 3rd hour a shroud of fog enveloped
me. Sometimes the fog is just temporary but this time it was here to stay.
By the time I decided to go it was too late to head to the top of the
mountain so I just headed for home.

The weather was unfavorable the next few nights as clouds and fog penetrated
all the way to the desert. My last attempt was on the morning of the 8th. On
this trip up I did not clear the fog until almost the 4000 foot level, which
is close to my observing site. I did not want a repeat of the 5th so I
headed all the way up the mountain beyond the reach of the fog. When I
arrived at the top the wind was blowing so hard I did not bother getting out
of my car. I decided to head back down the hill and put up with the fog. I
started counting at 0132 PDT or 0832 UT. That hour produced 13 meteors
(1 ANT & 12 SPO) under a LM of +7.05. The second hour produced 14
meteors (2 ANT, 3 ETA, & 9 SPO). The last 75 minutes produced 13
meteors (5 ETA & 8 SPO). I was grateful the sky remained clear until dawn.

While the rates were not impressive it was a good feeling to be back under
the stars. It was interesting that no Eta Lyrids were seen. It will be
interesting to see if any of these meteors were caught by the video camera.

I think my next effort will be for the Daytime Arietids and the June
Lyrids.

May 4
Interval                  RA  Dec  Teff      F   Lm  ELY ETA ANT  SPO
period 1000-1100 315 +20 0.750 1.00 6.66 C  0  C 4   C 0   C   3
period 1100-1200 330 +20 0.250 1.00 6.37 C  0  C 1   C 0   C   2

May 5
Interval                  RA  Dec Teff       F   Lm  ANT ELY ETA SPO
period 0830-0930 265 +20 1.000 1.00 7.27 C 3  C 0   C 1   C   8
period 0930-1045 285 +20 1.250 1.00 7.23 C 1  C 0   C 2   C  10

May 8
Interval                  RA  Dec Teff       F   Lm  ANT ELY ETA SPO
period 0832-0932 280 +20 1.000 1.00 7.05 C 1   C 0  C 0  C  12
period 0932-1032 295 +20 1.000 1.00 7.01 C 2   C 0  C 3  C   9
period 1032-1147 315 +20 1.250 1.00 6.99 C 0   C 0  C 5  C   8

Bob Lunsford