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(meteorobs) Leonids : 2 new possible impacts on the moon ?
Dear friends,
As we were waiting for the great LEO peak on november 18 evening at
Sobaeksan Observatory, Korea, the moon was high in the sky during the
begining of the show over USA. I had a video camcorder recording the moon
and Michael Lachmann (dirk@santafedot edu) was looking to the moon through
Fujinon 150 mm binocular ...
He saw one impact at 09H51 UT.
I now had a close look to the video tape and I'm almost sure I found this
impact. More, I found another brightest impact at 09H40 UT. Using some
reference star fields taken before recording the show, I suspect this
possible impacts to be mag 7 to 7.7 (9H40) and 8 to 8.7 for the Michael
impact.
I created a special webpage to present this images. Here is the Url of my
Leonid website
http://www.astrosurf.com/carnets-astronome/leonides/leonides_dos_intro.htm
Please follow the link : "Des impacts Léonides sur la Lune ?"
The full story is in french, but you can have a look at the images ; they
are provided in uncompressed jpeg (total 1.3 Mo)
with the reference star field and other artifacts images found in the
original tape.
My english skill is so bad, so here is a translation of this french page,
using Altavista Babel Fish translator.
I hope the following text is not too bad and you will be able to understand
it. It seems there is some amazing sentences or words in the Babel Fish
text, but it is still better than I can do !
I think Michael will send his own story as soon as he can ; I will forward
it.
Best regards,
Christophe Marlot
*****************************************
LEONIDES 2001, IMPACTS ON THE MOON?
In order not to harm the quality of the images,
no compression was used. This Web page is thus exceptionally heavy.
Thank you to have patience during the loading of the images. The file
conversion format mini DV into AVI, then in BMP using the software of
capture Pinnacle Studio DV then AVIEDIT gave images nonproportional,
lengthened in height. It deliberately was selected not to make
undergo additional conversions with these images and to present them
here with this slight defect.
TO SUPERVISE THE MOON...
THE MATERIEL USED
STELLAR FIELDS OF REFERENCE
ARTIFACTS!
IMPACT!
A SECOND IMPACT?
CALCULATIONS...
TO SUPERVISE THE MOON...
November 18 2001, 09H30 UT, SobaekSan Observatory, South
Korea. The Sun has been lying for a few minutes hardly, but the cold
is already intense: -4° C probably. First Leonides will not be let
observe before several hours in the sky of Asia... However
environment is not completely with the relaxation; the technique
dominates. It is a question of supervising the Moon in video in order
to capture there in images of possible impacts of Leonides! The
geometry of the couple Earth-Moon is such as the probability of
observable impacts is very strong. That was already succeeded by a handle
of observers
in 1999. There will be two peaks of activity into 2001: 10H00 and
17H30-19H00 UT Two chances to observe lunar impacts. If the second
peak is that which seems to offer the best possibilities to the
observers with really significant rates, the first peak is not to
neglect. It occurs in theory with the top of North America, whereas
on Asia the Sun comes to lie down and that the crescent of the moon is
sufficiently high in the sky to be likely all the same some to
succeed...
The MATERIEL USED
The combination optical and video used is the same one as that which
already was used successfully on June 21 2001 in Zimbabwe for
the total solar eclipse , or even on September 8 2001 to capture
the sequence of the occultation of a star of mag 7 by Titania.
A digital video camera Sony TRV 15 is used in afocal
behind L80/400 provided with an eyepiece 40 mm Plössl Celestron. The
video camera is used in supernightshot mode with 3 images second.
Under such conditions, magnitude 10 is rather easily reached on
individual images by quite black sky and magnitude 11-11.5 is reached
after compositage. A precise timing is preserved thanks to a stop
watch beeper fixed on clock speaking and leaf about 10 in 10 seconds.
STELLAR FIELDS OF REFERENCE
At the beginning of recording, 3 reference stellar fields were captured,
this in order
to make it possible to gauge the glare of possible impacts on the
Moon. Field 1 was captured with 9H24 UT, field 2 one minute later
and field 3 with 9H29. It should be noted that these fields were
captured with a zoom slightly lower than that which was used for the
capture of the lunar images in they-even. The profit in magnitude is
not very significant. One can locate the first two fields on both
sides of the Moon on the photograph of environment approximately
2° of the Moon. The extremely transparent sky was deprived of any
shape of clouds.
FIELD 1, AROUND THE STAR 1SAGITTARIUS
FIELD 2, AROUND STAR LAMBDA SAGITTARIUS
FIELD 3, AROUND THE MOON
ARTIFACTS!
One finds all kinds of things by viewing astronomical videotapes...
In very first place, one notes the presence of some " hot " pixels,
electronic noises or cosmic rays. The videotape of monitoring of the Moon
in
is not free; a first reading in showed at least 3. The aspect of
these hot pixels makes them easily identifiable. Here are two
examples, original images with the support, followed of a " resize "
300%.
It is different possibilities of artifacts; among
most probable appear the planes and satellites. The length of the
exposure time (0.33 sec) in supernightshot mode is enough to give
them a " moved " aspect. A plane was left trapped on the videotape "
impact "... Impostor is easily uncovered!
IMPACT!
9H52 UT! Our friend
Michael Lachmann (California, USA) with the visual monitoring, is
posted to a few 75 m of the video camera. He uses a pair of Fujinon
binoculars 150 mm 40X providentially abandoned for a time by their
worthy owner... " I saw one impact! Right now! " Forsaking his
monitoring, Michael brings the good news to us to the step of race.
The impact took place at 9H51 UT and was let foresee in the shape of a
dubious flash in full center of the lunar disc, enough far from the
terminator. To find this flash on the videotape was not
especially easy, but the following day, in less than 5 minutes, had
found we it... Or at least, we had found a vague luminous point being
able to correspond, exactly at the place indicated by Michael.
Captured image of a leonid flash on the Moon or that of
an artifact, or background noise? The presumption is strong to
be in the presence of a lunar impact, taking into account the
testimony of Michael. However the doubt remains and will be raised
only with a second independent testimony.
A SECOND IMPACT?
The videotape is then viewed partly. Very
quickly another potential impact appears with 9H40:01 UT..
Note: on this image one notices a point practically just
shining with the top of the lunar limb, in the lower part of the
image. It is about a constant luminous point related to the lunar
relief which appears on a very great number of images of the video and
not of a luminous point due to the background noise of the sensor.
CALCULATIONS... (Update December 6 2001)
The impacts presented here are for the moment on standby of a possible
confirmation... Several other suspect images were located on the
video, but in extreme cases of the background noise, it seems not very
probable that they can be Leonides impacts. Nevertheless this could
be to reconsider if visual observations carried out were to be
confirmed. Currently an impact magnitude 4 (?) seems to be confirmed
by 3 independent observers and to be recorded in video from the USA on
November 19 with 00H18:58 YOU. (Messages IOTA Joan and David Dunham
< dunham@erols.com > of November 25 2001) It
could seem astonishing that Michael could observe a flash with 09H51
UT and not to have seen a flash more shining ten minutes
before. Actually the monitoring carried out by Michael undoubtedly
began in the interval; it was not 100% complete. In addition, of
the consent of Michael, after its first success, ocular tiredness
arrived very quickly, as well as the impression to see flashs a little
everywhere... By having recourse to the stellar fields of
reference, one can risk an evaluation magnitude of the recorded
flashs, whatever they are. The flash observed by Michael roughly has
the appearance of a star magnitude 10 on the images, while the second
flash discovered would rather have an appearance voisinne of 9. If
one counts on the fact that a moderate Leonide flash on the Moon has
an average lifespan equal to 50-100 milliseconds (given IOTA obtained
in 1999), and not 330 milliseconds (exposure time of the images), it
is necessary to multiply by 6.6 to 3.3 the point brilliance of the
flashs to obtain a " exposure time equivalent 0.33 sec " and to be
able to compare with stars of reference. This gives us a magnitude 8
to 8.7 for the flash of Michael and 7 to 7.7 for the second flash
discovered... Glares completely comparable with what was already
observed in 1999.
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