Transit of Venus

Tom Randy wrote:
On Wed, 09 Jun 2004 03:49:59 +0000, Henry Spencer wrote:

In article ,
Robert Casey wrote:
In particular, check the iamge taken at 11:07 UT --- no black drop
visible there.

I don't see any teardrops either. Must be an artifact of the human eye.

No, it has been photographed during transits of Mercury (which also proves
that it is not a result of Venus's atmosphere).


I saw a photo of it yesterday on someone's web site.

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

--
Pat O'Connell
[note munged EMail address]
Take nothing but pictures, Leave nothing but footprints,
Kill nothing but vandals...

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.