Transit of Venus

As did I. Not everyone captured the effect, but it can be captured on
film. SWAG: an atmospheric effect?


I saw a lecture that stated that the effect was due to blurring caused
by a combination of diffraction effects and terrestrial atmospheric
turbulence, these are apparently exarcebated in small aperture
telescopes. A demonstration showed a white circle on a black background
approaching a white edge for different spacings (5..1 pixels)and
different applications of gaussian blur (using Photoshop or similar).
This produced an effect very like images of the black-drop effect.

--
J Whitby

James Whitby wrote:

As did I. Not everyone captured the effect, but it can be captured on
film. SWAG: an atmospheric effect?



I saw a lecture that stated that the effect was due to blurring caused
by a combination of diffraction effects and terrestrial atmospheric
turbulence,

For a more detailed explanation see Icarus 168 pp249-256 (2004),
abstract available from ADS:

http://adsabs.harvard.edu/cgi-bin/np...ea7c9b63a15607

--
Dr. James Whitby Tel: +41 (0)31 6314409
Physikalisches Institut Fax: +41 (0)31 6314405
Universitaet Bern
Sidlerstrasse 5
3012 Bern, Switzerland.

"Paul Schlyter" writes:

The Black Drop is an effect of how our eyes perceive when two unsharp
edges between bright and dark approach one another. It can be readily
simulated by keeping two of your fingers as close to your eye as you
can
and then let the fingers approach one another: they seem to touch
before
they actually touch.

They gave this example on NASA TV also, but it is a bit misleading
because the fingers effect is caused by diffraction (wave bending as a
sharp edge intervenes), whereas the black drop effect is caused by
variable refraction from moving air cells in Earth's atmosphere. Light
in space is not spread in this way, as is evident from photoelectric
observations of lunar occultations, which show the star disappearing in
milliseconds rather than seconds. (That effect really is caused by
diffraction.) -|Tom|-


Tom Van Flandern - Washington, DC - see our web site on replacement
astronomy research at http://metaresearch.org

In article ,
randyj wrote:
is that the same thing as seeing the drop effect in front of the sun?
somebody else explained on here, i think it was at metaresearch.org
or something, that it is due to moving cells of air in the atmosphere.

I'm not sure what it says at metaresearch.org, but since the black
drop effect was seen when Mercury transited the sun as observed by a
spacecraft, the black drop effect cannot be due to either the earths
atmosphere or the atmosphere of the planet in transit.

In article ,
Tom Van Flandern wrote:
They gave this example on NASA TV also, but it is a bit misleading
because the fingers effect is caused by diffraction (wave bending as a
sharp edge intervenes), whereas the black drop effect is caused by
variable refraction from moving air cells in Earth's atmosphere.

The black drop effect cannot be from an atmospheric effect, Pasachof
has observed the effect on the planet Mercury from the TRACE
spacecraft.

Probably the visual-perception effect of two objects of roughly the same
brightness (or in this case darkness) bleeding towards or into one another.
A trick of perception. What I find curious is, at least to my knowledge,
the assertion that this effect was caused by the atmosphere of either Venus
or Earth was still in print fairly recently, despite the counter evidence of
Mercury transits at least for the Venus atmosphere case.
--
Sincerely,
--- Dave

----------------------------------------------------------------------
A man is a god in ruins.
--- Duke Ellington
----------------------------------------------------------------------

"Greg Hennessy" wrote in message
...
In article ,
Tom Van Flandern wrote:
They gave this example on NASA TV also, but it is a bit misleading
because the fingers effect is caused by diffraction (wave bending as a
sharp edge intervenes), whereas the black drop effect is caused by
variable refraction from moving air cells in Earth's atmosphere.

The black drop effect cannot be from an atmospheric effect, Pasachof
has observed the effect on the planet Mercury from the TRACE
spacecraft.

wrote:

I'm surprised


What surprises you is irrelevant.

that nobody has asked


Who is this nobody and why should he/she ask?

about appropriate music for the transit of Venus.


Why should the transit of Venus require appropriate music?

Naturally, it would have to be the "Transit of
Venus March" by John Philip Sousa.


What seems natural to you is irrelevant.

--
Freddie 'fag' Shorts

I'm loud and I'm proud. I'm gay and I like it that way!
Another proud buttplug owner. Honk if your horny!
I support Gay Pride! The Ramrod rocks! Kerry sux!

Wanna hire me for web site development? I'm way under-employed!
Contact me by email ) or mail me at
FS Newssite Inc.
101 West 23rd St. Suite 2237, New York, NY, 10011
On second thoughts, don't bother. Just sign me up for subscriptions.
I like to steal copyrighted material.

Check out my current web sites -
http://www.orwellian.org
http://www.miscstuff.org
http://home.nyc.rr.com/cypherpunk/

I'm really proud of this -
http://Frederick.Shorts.swellserver....orldrecord.php

http://www.plugger.info
http://www.pluggers.com/daily/

wrote:

Nicolai P. Zwar writes:

I'm surprised that nobody has asked about appropriate music for the
transit of Venus. Naturally, it would have to be the "Transit of
Venus March" by John Philip Sousa.

Another obvious choice would of course be "Venus", from the planets.
Though "Transit of Venus" sure nails the theme down.

By the way, in case you do not have any special glasses, I have found
that you can wonderfully watch the Venus transition if you hold one or
two CDs in front of your eye(s). No kidding.

Readers, don't try this if you value your eyesight. Reducing
the intensity of sunlight to the point that it becomes comfortable
does NOT guarantee that no damage will occur.


Do not look into laser with remaining eye.

--
Freddie 'fag' Shorts

I'm loud and I'm proud. I'm gay and I like it that way!
Another proud buttplug owner. Honk if your horny!
I support Gay Pride! The Ramrod rocks! Kerry sux!

Wanna hire me for web site development? I'm way under-employed!
Contact me by email ) or mail me at
FS Newssite Inc.
101 West 23rd St. Suite 2237, New York, NY, 10011
On second thoughts, don't bother. Just sign me up for subscriptions.
I like to steal copyrighted material.

Check out my current web sites -
http://www.orwellian.org
http://www.miscstuff.org
http://home.nyc.rr.com/cypherpunk/

I'm really proud of this -
http://Frederick.Shorts.swellserver....orldrecord.php

http://www.plugger.info
http://www.pluggers.com/daily/

"Greg Hennessy" writes:

I'm not sure what it says at metaresearch.org, but since the black
drop effect was seen when Mercury transited the sun as observed by a
spacecraft, the black drop effect cannot be due to either the earth's
atmosphere or the atmosphere of the planet in transit.

I saw my first transit of Mercury and first black drop
effect in 1960. It has always been obvious that the atmosphere of the
transiting planet has nothing to do with the black drop effect because
Mercury has no atmosphere.

But think about what you are saying. Earth does have an
atmosphere, and the light from the transit must pass through it. Our
atmosphere slightly distorts all light passing through it. Why should
transits be an exception?

Lunar occultations prove that the apparent enlargement of
the Sun's and Moon's disks caused by irradiation does not occur in
space. So it must happen in Earth's atmosphere. And stellar "seeing"
disks show that it does happen here, caused by variable refraction in
moving air cells.

At the Meta Research site you will find the evidence and
details. See
http://metaresearch.org/home/viewpoint/blackdrop.asp.
Be sure not to be one of those people who can't unlearn things once
learned wrongly. Look at the evidence and draw your own conclusions
anew, without the influence of the bias of having previously held a
contrary position. -|Tom|-


Tom Van Flandern - Washington, DC - see our web site on replacement
astronomy research at http://metaresearch.org

In article ,
Tom Van Flandern wrote:
But think about what you are saying. Earth does have an
atmosphere, and the light from the transit must pass through it. Our
atmosphere slightly distorts all light passing through it. Why should
transits be an exception?

You are proposing a logical fallacy.

Earth's atmosphere distorts light.
The black drop effect is a light distortion.
The earth's atmosphere causes the black drop effect.

The logical fallacy is because other effects besides the earths
atmosphere distort light.

If the black drop effect is from the earths atmosphere, how come the
TRACE sattelite saw the effect?