Θα μου επιτρέψετε να παρουσιάσω την συλλογική αυτή προσπάθεια στα Αγγλικά, προκειμένου να την διαβάσει ο έτερος φωτογράφος μας από την Ιρλανδία! I already had known that this attempt required wide range cooperation, but i hadn't imagined that each section would be taken over by a different person. That's what we call team-work! The volunteer was a friend named James, we met at Parnon mont, last August. I should send him an email, to let him know what things would be nessesary for all this. As for us, Kimon Papathanasopoulos would be our photographer. So, the data needed for this attempt to be successful were the following: 1. Accurate geographical position for each observing location. 2. I had made some simulations about the UT time convenient for both and i found out that the ideal UT time was 17:15. So we had to capture the event at the same moment/time. 3. The picture should include both Moon and Venus as much as possible at the same magnification. That'all! After all these, the final images should be composed in one with just one crescent Moon and two "Venuses"! Of course, two "Venuses" were the result of parallax phenomenon due to the distance differences between Earth and Moon-Venus. With this composition available, we could measure the Moon diameter (in image scale unit, e.g. pixels) and the distance between two "Venuses", in the same unit. After that we should take a look at a planetarium software, to know the angular Moon diameter, at the specific UT moment. Using the ratios "apparent pixel diameter" and "true angular diameter" of these celectial bodies, we could find out the true Venus shift, due to parallax!!! Finally, the things would become very easy! Trigonometry would be our next tool. Let's see these in practice! We can see the Kimon's image at the picture 1. The James' image at picture 2. Since i don't know anything about Photoshop for the two images to be composed, i asked Yannis-eclipticman-Efremidis to help me out with this. The very impessive and helpful final composition Yannis made, is at Picture 3. So, here are the data: Distance between us and James was 2821,45 km=a, as i measured it with Google Earth, given the accurate coordinates. From the picture 3 we can measure the Moon pixel diameter into 290,62, and Venus pixel shift into 223,44. Cartes d'Ciel software gives the Moon true diameter 0,493333 degrees. Thus, the derived true Venus shift equals 0,379293923 degrees=b It is important to understand that this shift angle represents the top angle of a isosceles triangulum, in which Moon is at the top angle and the two observing positions at the other two angles. Time for trigonometry! tan(b/2)=(a/2)/x, where x the unknown Moon-Earth distance. The final x value was impressive: x=426203,99890km!!!!!!! And it is such, because the Moon-Earth distance as seen at the Cartes software, was 403917,1km. What this means, only 5,5% deviation!!!! We want to go further and search for the causes of this deviation! Vaggelis Tsamis told me that we must take into account the linear velocity difference between the 2 locations, due to different latitude. I suppose that Earth curve might affect the final result. We must cosinder the distances errors at Google Earth, as well as the errors related with the photos we took! James, Kimon, Yiannis, Vaggelis Thanks you for your cooperation!!!!!!! Picture1 Picture2 Picture3