The graph below is the predicted topocentric umbral semi-diameter expected during the partial lunar eclipse of 2001 July 5. This graph was produced from the output of a QuickBasic program called ViaX.BAS which calls data for the position of the Calwell Lunar Observatory and the Besselian elements found by other software for this eclipse.
The aim is to record images of the Moon during this partial eclipse, process them for measurement and then measure the semi-diameter of the umbra with commercial software Image Analyst. These measures will then be compared to that predicted in the graph to find if any umbral change has occurred during this eclipse. Any such change will be related to the conditions in the upper atmosphere responsible for the geometry of the umbra.
Observers are encouraged to provide me with copies of their images for analysis along with details of the observer and their location (longitude, latitude and elevation) so that their site data can be produced.
The topocentric umbral geometry and a description of the variables Fi the topocentric umbral semi-diameter and delta, which is the slope angle of the edge of the umbra are both described in the Appendix to my analysis of the total lunar eclipse of 2000 July 16.