Ouch, Doug!
You got me again. It's 346.3 meters per pixel,
not 0.3463 meters. Multiply everything by 1000.
Note to self: no more cyphering in the head
while heavily medicated.
Method: mean distance = 400,000 km rough
(apogee = 405,696 km; perigee = 363,104 km)
Divide by 60 x 60 x 60 (deg x min x sec) = 216,000
yields about 1850 meters per arc-second, then
multiply by 0.187 arc-second per pixel which is
about halfway between 18 squared (324) and
19 squared (361). I then repeated these mental
steps on a calculator to get more precise results
but somehow managed to forget that it was
KILOmeters, not meters...
Like I said, Heavily Medicated...
The 200 km size of the image square (this page
wasn't up when I checked them this morning, or I
couldn't find it) indicates that they were either "binning"
the pixels in the CCD, hence about 346.3 x 2 = 692.6
meters per pixel, or I made a wrong assumption about
the view of view they were using. (The CFHT has
three different setups for differing fields of view.)
http://www.cfht.hawaii.edu/News/Smart1/
The "corners" ARE diffraction spikes, they
say, at 45 degrees to the image orientation, which
clearly shows in the animated gif of the impact
(now that they've had time to clean the images up).
The contour map of the flash shows a slightly
elliptical flash elongated in the direction of motion.
Their MVA chart of the impact site shows it to be
on a hillside, a not-unlikely outcome if you're zapping
almost horizontally over the Moonscape at 1930 m/sec.
Not safe driving. It's a very noisy low contrast image,
straining to get the flash location, no doubt. Lehmann C
and Drebbel D show up in the images, but the rest of
terrain is just a jumble.
The originally released raw image looked too
square (so over-saturated). That helped to fool me,
but it was greatly aided by making too many quick
assumptions, speculating too easily and facilely,
and -- oh, yeah -- forgetting that it was kilometers
instead of meters.
Just let me be a bad example for everybody...
Sterling K. Webb
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----- Original Message -----
From: "MexicoDoug" <[EMAIL PROTECTED]>
To: "Meteorite Mailing List" <meteorite-list@meteoritecentral.com>
Sent: Sunday, September 03, 2006 7:55 PM
Subject: Re: [meteorite-list] SMART-1 SMASHES
Sterling wrote:
each pixel would resolve about 0.3463 meter at the mean
distance of the Moon, and the observed flash would
therefore cover a 7.6 to 8.0 meter square.
...
Any other explanations of a "square" impact flash?
Hello Sterling:
35 cm on the Lunar surface? That would be Totally Unbelievable! A camera
connected to a telescope on Earth that can distinguish a foot by a foot
(35cm ) square on the moon through the Earth's atmosphere, they could
actually take some nice pictures of the old Lunar modules and stuff right
from Hawaii. I know technology has progressed but that would be awesome!
If Dawe's Limit ("theoretical" in quotes) has any relevance to the
telescope-camera combination. The very best that could be done would be
about 60 meters x 60 meters per pixel. But their pixels in the image with
atmosphere and all, resolution appears to be over ten times worse.
I took a Sear's Stanley tape measure to the picture of the explosion from
the Canada France Hawai'i Telescope which they say is 200x200 km, and from
that get that the flash is about 15 kilometers by 15 kilometers, not your
8
by 8 meters (don't follow how you got that (there's a lot of theoretical
atmospheric and optical limits beyond me to deal with since the camera has
a
big reflector and a quarter of a million miles in front of it.) Sorry
about
the low tech check.
As a cross check, in their published image there are indeed about 22-23
pixels up and down and across - sometimes.
That would say that it is about 11.5 km x 11.5 km, only 2 million times
more
area than you suggested. (400 x 400 pixel image size, the blast covers
(23/400*200,000)^2). Note how many features look like squares and
rectangles (better in my enlarged image below).
http://www.cfht.hawaii.edu/News/Smart1/
Then, if 15 km equals 23 pixels, they are getting 650 METERS (OK maybe as
low as 450 meters) per pixel, not 35 CENTIMETERS per pixel and Big Brother
can't read the license plates on the Lunar rovers yet.
As to the "square shape", I think it's like looking at clouds on the
Oklahoma plains and you see what pleasures you. There appear to be
spashes
around all the edges to me and some nice new SMART-tektites to go-n-get.
I
can easily count 30 pixels up and down in some parts. But maybe you've
got
a good theory there, nothing proves it's not a square.
I've posted an enlargement of the explosion showing with the individual
pixels posted on the CFHT page here:
www.diogenite.com/smart.JPG
for anyone curious about the shape of the explosion, which clearly shows
rays of light like splashes and, maybe or maybe not, coincidentally, four
of
them defining Sterling's "square". It is even more coincidental that the
square would happen to be perfectly setting horizontal in the image - or
yikes, that could that be enhancing a perception or illusion. Try
rotating
it in your image viewer. Who knows. The Shadow?
Best wishes, Doug
PD, IR might be the favorite choice since it gives better night vision,
so,
I guess we all forgot to put the Russian goggles on our scopes and
binocs...
In any of the articles did it actually say someone saw real time a flash
in
the visual light's range?
Sterling K. Webb
--------------------------------------------------------------------------
------------
----- Original Message -----
From: "Darren Garrison" <[EMAIL PROTECTED]>
To: "Meteorite List" <meteorite-list@meteoritecentral.com>
Sent: Sunday, September 03, 2006 9:18 AM
Subject: Re: [meteorite-list] SMART-1 SMASHES
http://esamultimedia.esa.int/images/smart_1/observation_SMART-1_hawaii_H.jpg
http://www.esa.int/esaCP/SEM2N58ZMRE_index_0.html
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