Results : a movie - showing the transit from
the beginning to the end (0728-1322 CEST = 0528-1122 UT)
Results : photos - the image to the left is a combination of 4 images taken with 100 minutes separation - photographer : Leif Moeller (EUC Syd)
et al, and is copyfree within press and astronomical applications.
A selection of our 400 images may be found at this page, and are copyfree on the same conditions too.
"So what is all this up to ?"
We have been able to measure the distance between our planet Earth and the Sun. by comparing images from Denmark with say images from e.g. South Africa, Australia, Indian Ocean etc. Images from different locations do show a tiny difference. Astronomers do call this effect : "Parallax".
This magnificent spaceweather article describes how captain James Cook back in 1768-69 was send to Tahiti in order to measure this Venus transit parallax.
Parallax - August 2004 - the Astronomy Class.
The first Pretorian images right below are orientated with Geographical North up.
This South African image is
courtesy of the Pretoria Centre of the Astronomical Society of Southern Africa -
click to visit their page - and
was captured at 12 57 27 Local time = 10 57 27 UT (image #355).
Our corresponding Danish image 391 was taken at 12:57:35 = 10:57:35 UT.
The difference between these images clearly reveals the parallax.
Click to see a 200 kB GIF animation on this parallax.
All images below are orientated with Solar North up.
A bit confusing : in solar astronomy there are several definitions of North.
The Solar North orientation is solar-observatory standard - however - relatively to Earth based Geographical North there is a slight difference equal to 12,42 Degrees CW - (June 08, 2004) (Technical details on how these images were orientated may found at this page)
Reunion Island vs. Denmark
A clear parallax effect is
visible when comparing our Danish images (+55N, 10E) - with images from Reunion Island (-21S, 55.25 E)
Thierry Payet - ARECA .
The image to the left shows the difference between photos from these two locations (false colours) - please notice the parallax is visible as a white shadow.
This link will show you a 200 kB GIF animation comparing all images.
This link will show you the images from Reunion Island (c) Thierry PAYET
This link will show you the nearly simultaneous Danish image (combination of two exposures, data given at the end of this page.
Parallax images were in all cases rotated so that Solar North is up, and all tracks become parallel - if interested in details, please see remarks at the end of this page.
Australia vs. Denmark.
In addition, a parallax effect may be observed when comparing our Danish images with
Australian images, courtesy :
Learmonth Observatory.
This parallax effect is on the order of roughly half a minute, as may be predicted by mathematical calculations.
Click to see an animation shifting between Australian and Danish images
Click to see an animation of the Australian images, as placed on GONG.
Click to see an animation of Danish images - 121 kB - 4 x 100 minutes.
This parallax effect may be observed in details if we take a look at the Australian IPS images (c) - from the GONG project at Learmonth Solar Observatory.
We now compare
Click to see a GIF animation, shifting between these images (250 kB) - as well as the difference .
Please notice, there is a significant east west parallax too - this is a 3 D effect :
Australia is placed far East of Denmark, thus Venus as seen from Australia appears to be moving west- this
effect increases at Australian sunset (image).
We do appreciate the positive feedback from the Australian IPS staff -
these
IPS images above are (c) and courtesy GONG/NSO/AURA/NSF (c) - this work utilizes data obtained by the Global Oscillation Network Group (GONG) program, managed by the National Solar Observatory, which is operated by AURA, Inc. under a cooperative agreement with the National Science Foundation. The data were acquired by instruments operated by the Learmonth Solar Observatory, Udaipur Solar Observatory, and Instituto de Astrofisica de Canarias.
Contact the IPS staff for repro-permission. Rules of copyright
Conclusion : This Venus Transit 2004 was a most challenging event - we did take more than 400 images - click to see a selection .
And much more is to be done, next school year we hope to publish a full science report on how to find the Solar distance.
Working at the observatory that day :
Ib Jansen, Jeppe O. Petersen, Karen P. Olesen, Kim Christensen, Leif Moeller, Lotte Lennert, Martin S. Rasmussen, Mogens Winther, Rasmus Flytkjaer, Simon Delpin, Tom Pelle Fabricius, Torben Krogh.
This event was a joint undertaking by EUC Syd and AGS.
Please feel free sending an email to astronomy students and teachers at Astronomy Group Sonderborg
Venus setting in the evening sky of May 09, 2004 - 1936 UT.
Camera data : Canon EOS 10D - 6,3 Megapixel resolution, donated by Danish Science Communication. Click at the image for full resolution.
Telescope data : 5 " APO Meade, f = 1140 mm , mounted pb at our 16 " SCT.
These images will be copyfree for newspaper and educational purposes - provided this source "EUC Syd and AGS" is mentioned, informed and linked.
During the transit itself, the observatory was opened to public.
More information on this historical transit, including international links -
and latest news : VT-2004
Danish Tycho Brahe Webpage with national links
Remark : North-South orientation is a big problem - due to the missing sunspots.
We have orientated our images by 2,4 degrees CCW images in order to get the same venus track as the professional Australian observatory mentioned above. Doing so it was implicitly assumed that the Venus tracks observed from Australian and Denmark were indeed parallel.
This is strictly speaking a first order approximation, however - the facts that these tracks are being approximately straight lines shows this assumption is reasonable.
Please also observe this figure given in this VT-2004 chapter.
Images from Reunion Island were rotated on a similar way - forcing the tracks to be parallel with the original Australian images.
Anyway, we will avoid this minor 3D problem if we are able to find observatories at approx same longitude as ours. Example of 2D Math method.
Data concerning the comparison
TP : Image 00308 is taken at 11:00:43 pictures
DK : Image 394 is taken at 11:00:33.
TP : Image 00068 is taken at 06:47:35 UT
DK : Image 141 is taken at 06:47:33 UT.
- photo : Martin S. Rasmussen
