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EL CYBERASTRONOMO
NOVIEMBRE 1999
CREADO EN 1997                                                          NO. 57



TRANSITO DE MERCURIO: REPORTES CENTROAMERICANOS

EL SALVADOR
El 15 de Noviembre de 1999, nos reunimos en el Observatorio Astronomicode
San Juan Talpa, La Paz, El Salvador. Ramon Rossel, Ricardo Lewy,Jorge
Colorado y muchos invitados, aunque contabamos con el telescopiode 10"
Cassegrain de la Asociacion no lo utilizamos ya que desde haceunas semanas
atras estamos trabajando en automatizar la montura. Y eltelescopio de
nuestra miembro Guillermina Reyes un reflector de 28"pero no teniamos un
filtro solar suficientemente grande como parautilizarlo. Usamos dos
telescopios un Smith-Cassegrain de 8" y 5". Alcual le adaptamos dos
camaras  Pentax y con las cuales fotografiamos elevento.Lic. Ramon Rossel tomó cada 5
minutos una fotografia de el transito.El cielo estaba completamente
despejado y vimos todo elevento...descubrimos que el Sol esta en actividad
ya que habianbastantes manchas solares. De hecho el dia de ayer pude
observar desdeel atardecer en la playa ¨La Costa del Sol¨ (El Salvador) una
mancha solar a simple vista.  Disfrutamos mucho el evento del transito solar
y proximamente mandaremoslas fotografias scaneadas

PANAMA
Felicidades! En Panamá no tuvimos tanta suerte. Por lo menos en el área de
la ciudad.Justo antes de comenzar el tránsito, una nube enorme tapó el Sol y
después cayóun tremendo aguacero.Esperamos ver las fotografías de ustedes
pronto.Héctor Polo

GUATEMALA
Un grupo de astronomos (Stuardo Schmid, Roberto Monterroso, Rodrigo Roesch y
Edgar Castro, por aparte Mario Ortiz y Eduardo Rubio) observaron el transito
del planeta Mercurio sobre el borde norte del Sol. Esta observacion tuvo
caracter espectacular e historico, pues en la historia de la astronomia
guatemalteca nunca se habia realizado la observacion de un transito. El
fenomeno fue visto desde las 3:12 pm (hora local) en adelante, y se
observaron manchas gigantescas, que a comparación con el planeta lo
superaban en tamanio.



ESPECIAL:  DESDE HAWAII   STEVE OMEARA   NOS REPORTE EL TRANSITO DE MERCURIO Y LAS LEONIDAS
(SIN TRADUCCION)
 

Mercury Transit
Volcano, Hawaii.

Well, I saw the Mercury transit, but only about 3/4 of it -- a big cloud
moved in and covered the Sun for the duration of the last 1/4. But I have
to preface this report with some Murphisms:

1) First, and foremost, I have never seen a Mercury transit, so I did not
know what to expect.
2) I figured that the November issue of Sky & Telescope would tell me what
to expect, but I the magazine I expected to come in the mail never did --
and still hasn't. I received the December 1999 issue, though.
3) Edwin, the copy you said you'd send to replace the lost issue never came.
and
4) the mylar that Gary said he'd send never arrived.late now of course
--sp so I went and bought some Pop Tarts          :-)

Okay given all these failed expectations, I went to S&T's web site and
pulled down the map and read the text about the Mercury transit on the news
page. But that didn't say anything about what to expect -- as far as what
Mercury should look like. So I made my own best guesstimate: My
expectations said the planet would be quite an obvious inky black spot --
darker than any sunspot....Hah!

Now for something completely different: The time for 1st contact listed on
the S&T web page was 11:13 a.m. HST for Honolulu. Hilo is further east than
Honolulu, and the time difference is 10 minutes. We're in Volcano, so
that's another minute (really 44 seconds). So contact should have occurred
around 11:02 a.m. Fine.

At 10:50 I brought my 4-inch Genesis up to the USGS Hawaiian Volcano
Observatory, which is at the 4,200-foot-high summit of Kilauea Volcano.
There I projected the image onto a box with white paper. We had clear skies
and all that, and the Sun was quite entertaining with all its spots. So it
wasn't difficult to get people excited about the coming event. But come
11:00...no sign of Mercury. I was using 23x and magnifying the image of the
Sun  by varying the distance of the paper from the eyepiece. So we had an
appreciable disk. By 11:05 about a dozen eager volcanologists were waiting
for Mercury to perform. But still no Mercury. Then I thought perhaps the
diagram on the web page was wrong and the event should happen at 11:13 in
Hilo! Come 11:13... still no sign of Mercury. By 11:20, the volcanologists
were getting restless. Now, the only thing performing was me, cracking
jokes, making light of the situation, because, quite frankly I had no idea
what was wrong.

By 11:20 some volcanologists were yelling to get the hangman's noose!
Just as the crowd of scientists were getting rowdy, and I saw my life and
reputation on the line, I suddenly thought to increase the power. So I put
in 74x and pulled the paper back. After perhaps another minute of
searching, there was Mercury, with about its disk just moving fully onto
the limb of the Sun, displaying the famous black drop effect. My life was
saved (but I don't know about my my reputation). Then, slowly, the planet
slipped fully onto the face of the Sun and began marching across the
surface, just kissing the northern limb. By 11:30, clouds had begun to
interfere, though now the tiny 4.4' gap between Mercury and the Sun's limb
was clearly defined, with solar limb darkening quite pronounced. Then all
went dark, as a big cloud moved overhead and stayed overhead.

Without doubt, the reason I did not pick up Mercury sooner was because of
the low power and low contrast of the planet against the Sun's limb. (Were
these observational tips included in the Mercury preparation writeup? Just
curious, since I still don;t have a November issue.)

SOME OBSERVATIONS
When Mercury was entering the Sun's limb it was not as inky black as I had
suspected. In fact, it was more like a dark gray mote; almost all the
visible sunspots were more dramatic and darker than it. The planet also
appeared much smaller than I had anticipated. When Mercury first dropped
onto the face of the Sun, the preceding limb displayed a distinct yellow
ring around it; the following limb appeared clearly pinched in on the
northern and southern sides, giving the following edge an anvil- or
wedge-shape to it -- it looked much like the Double Sun optical phenomenon
seen at sunset.

As William Sheehan describes in his book *Worlds in the Sky,* these
observations are consistent with historical observations of Mercury
transits. In 1707 John Flamsteed noted a fuzzy ring around Mercury while
observing at Greenwich. This showed, he wrote, that the planet was
"encompassed by a thick haze or atmosphere." The ring was also seen by
a number  of later observers, such as Johann Schroeter, who, during the
Mercury transit of 1799 , said its texture was a "mere thought." More
contemporary observations also reveal similar effects, such as that by
Richard Baum at Chester England in November 1973. All these observations,
of course, are contrast effects.
 

The black-drop effect lasted much longer than I had expected! I had
imagined it would be like looking at the green flash -- something that
happens in an instant. Instead, the effect lasted perhaps for a minute, for
the planet was traversing the Sun very close to the northern limb. As the
planet moved away from the limb, the pinched aspect diminished until the
planet appeared perfectly round. The illusion of a bright ring around the
planet remained throughout the entire observation period. The most dramatic
view of this was at 11:30 HST when Mercury's tiny disk and bright ring was
midway across the Sun and totally immersed in the smoggy yellow limb
darkening there at the northern limb.

See what happens when you miss one issue of Sky & Telescope!
I intend to make a drawing of these effects and send them to you. Okay?
Steve O'


LEONIDS:
November 17, 1999

I went out the summit of Mauna Kea and watched and photographed the shower
for 6 hours beginning at midnight. Highest single visual count in 1 hour
was 39 meteors between the  3:00 and 4:00 a.m. Nov. 17th HST (13-14hrs UT).

The activity picked up steadily during the night:
12:30 -1:00 HST (ZHR = 26.33)
1:00-2:00 (ZHR = 40)
3:00-4:00 (ZHR = 74.85)
4:00 -5:00 (ZHR = 41)
42 percent of the meteors were between mag. -3 (only one) with the mean
being magn. 0.5.
58 percent were between magnitude 2 and 5, with the mean being 3rd
magnitude.

The activity came in distinct waves, meaning there would be long periods of
inactivity followed by strong bursts of rapid activity where meteors fell
in succession, sometimes 4 in one second, followed by one every minute,
then ten in four minutes. These bursts would last 15 minutes or so,
followed by a lull of 15 minutes then another increase in activity.

Fireball activity also increased as the morning progressed. From 12:30 a.m.
HST to 2:00 a.m HST I saw no meteors brighter than magnitude 1, and there
was only one of those.

Between 4:00 and 5:00 a.m. HST, more than half of the meteors were brighter
than magnitude 1. And this ratio continued until 5:45 a.m in the very
bright dawn. In fact the brightest and most impressive meteors appeared
then, and they seemed opalescent against the royal blue sky infused with
red near the horizon, and   the powder blue cloudscape 7,000 feet below us.
What a glorious sight! One not to be forgotten.

I also had the 4-inch genesis with me and spent maybe 10 minutes looking at
the radiant to with a 3º field of view and 23x to see if there were any
faint sandy bits burning up there like gangbusters, but didn't see a one.

By the way, there were NUMEROUS very bright non-Leonid fireballs, and 75
percent of them were Taurids! The Taurid show rivaled the Leonids, with
some spectacular blazing fireballs and explosive terminal bursts and
prolonged trains. So there were two fantastic events going on
simultaneously, and I would be surprised if many non-astronomers weren't
bedazzled by Taurids rather than the Leonids!

Check Neil Bone's book on Meteors -- S&T pub. and notice that the Taurids
have a double peak which extends through out the middle of November.
Taurids have produced brilliant fireball displays in the past, in this year
should be counted high among them!

Steve O'



LEONIDS
November 18, 1999
I went the south flank (coast) of Kilauea (where lava was on cliff) and
watched and photographed the shower for 6 hours beginning at midnight. The
first two hours were in moonlight and the radiant was just rising. I saw a
few Leonids -- fireballs -- but only a few. Things really picked up around
2:00 a.m. HST (12 hrs UT). Between 2:00 and 6:00 a.m. HST (12:00-16:00 UT)
I recorded 227 meteors, and fully 44 percent of them were seen between the
hours of 5:00 and 6:00 HST, when I recorded 100 meteors.

Here are the calculated hourly ZHRs:

2:00 - 3:00 (ZHR = 104)
3:00 - 4:00 (ZHR = 129)
4:00 - 5:00 (ZHR = 90.5)
5:00 - 6:00 (ZHR = 182)

I saw  three meteors of magnitude -3 and six of magnitude -2. Here's the
percentage breakdown of all the others:

-1 = 17 percent
  0 =   8 percent
  1 = 21 percent
  2 = 12 percent
  3 = 17 percent
4/5 = 20 percent

So, as you can see, half of the meteors were between 1st and -3 mag. and
the other half were between 2nd and 5th. Therefore, unlike the reports from
Egypt and Spain, Hawaii experienced quite a bright display of meteors! With
the mean again being about mag +0.5.
Once again, the activity came in waves, but the lulls were much shorter
than during the previous morning. And the meteors fell almost continuously
from about 3:00 til dawn, with, once again, a continual splash of meteors
from 5:00 to 6:00. Also like the previous morning, bright meteor activity
(mag 0 and brighter) increased as the morning progressed.

                Mag 0 to -3 meteor counts
-----------------------------------------------
2:00 - 3:00 = 7
3:00 - 4:00 = 12
4:00 - 5:00 =  8
5:00 - 6:00 = 31
Of the 100 meteors observed 5:00 and 6:00 a.m. HST, Fully one half of them
were magnitude 1 and brighter. Interestingly, Donna woke up at 5:00 and
stepped outside and said she saw 5 meteors fall in rapid succession, all
bright, and each had a silvery sheen (like the opalescence I had mentioned
in yesterday's report).

SPECTACULAR WAVES AND BURSTS
As I mentioned, unlike yesterday morning's 15-minute lulls, this morning's
lulls only lasted a minute or two. In between were spectacular rapid-fire
bursts of meteors. This type of activity began suddenly and dramatically at
3:30 a.m HST (13:30 UT) just as Venus was rising. The intitial burst
ejected 5 meteors in 2 seconds on all sides of the radiant, followed by a
twin 3rd-magnitude meteor heading south bracketed by two fireballs.
Activity then stabilized with one meteor falling about every 6 seconds for
the next five minutes.
The 4:00 hour opened with four rapid-fire -1 "fireballs" , then
activity came in spits over the next few minutes. Until about 10 minutes later when
there was a dynamic BURST of seven 1st magnitude meteors that all flew to
the north simultaneously (that certainly perked me up!)!!! Then meteors
began falling at a rate of about about 1 every 10 seconds or one every 5
seconds on average for the next few minutes, with occasional bursts of
several meteors per second. Instead of a meteor shower, it was more like a
meteor sprinkle.

As fate would have it, the radiant tossed a lot of meteors to the north,
where a pond and river of lava lay at the crest of a steep hill on the
southeast flank of the volcano. So as the meteors feel, the lava flared and
bathed the clouds above them with a red light, while the ocean at my side
pounded the black lava cliffs with unbridled energy. Quite a powerful,
though peaceful spectacle. I'm glad I decided to wake up and check the
meteors out, despite the fantastic displays over Europe and Africa. Looks
like they sent a lot of the brighter meteors my my (thanks!)

TAURIDS AGAIN 
At the opening of the night, the Taurids were matching the Leonids one to
one. In the first half hour I counted 11 Taurids, and half of them were
between 1st and 0 magnitude. Then, suddenly, the Taurids essentially shut
off -- just like that...poof. Gone! But I did see a few Taurid stragglers
throughout the night. But initially the Taurids were truly matching the
Leonids: One Leonid would fall, then a Taurid would fall, then a Leonid,
then a Taurid.

Steve O'
END



ASTEROIDES

** Las Leonidas no se pudieron ver bien en America, pero en Espana se
observaron 1800 por hora!

** Tambien en el Oriente Medio se observo un buen despliegue de estrellas
fugaces, sobre todo en el desierto Arabe y cerca de Jordania.

** "El Cyberastronomo" es un boletin electronico de noticias de
astronomia que dese 1997 llega a varios paises de Centroamerica.

** El nuevo milenio empieza el 1 de enero de 2001, el anio 2000 pertenece
todavia al siglo XX y al 2do. Milenio

** El 14 de Diciembre se observa otra lluvia de estrellas denominada "Las
Geminidas". Esta es mas comoda de observar pues Geminis se levanta a eso de
las 7:30 pm. El ZHR es de 50 a 80.

** ZHR Zenital Hourly Rate, es la cantidad de meteoros que un observador
experto puede ver por hora bajo un cielo donde son visibles estrellas de
magnitud 6.5



EL  CYBERASTRONOMO, boletin electronico de noticias y comentarios de Astronomia,
creado en 1997 por Edgar Castro Bathen en Guatemala, Centroamerica.
Contactos: cyberastronomo@hotmail.com
http://homepages.msn.com/Terminus/cyberastronomo/