These pages are prepared and maintained by Byron W. Soulsby, a research amateur astronomer who operates the CALWELL LUNAR OBSERVATORY in Canberra, Australian Capital Territory situated in the south-east of mainland Australia.
The lunar eclipse information is generated by a suite of exclusive software programs first prepared in 1984 in Microsoft GW Basic and developed to run on the Macintosh computer under Microsoft QuickBasic.
The lunar eclipse ephemerides are based on initial data obtained from the Astronomical Almanac (AA) and/or from the US Naval Observatory Interactive Computer Ephemeris (ICE) software; particularly for the re-analysis of historical lunar eclipses and where data is not yet available from the AA.
Research papers have been published in the Journal of the British Astronomical Association (JBAA), the Australian Journal of Astronomy (AJA) and the Publications of the Astronomical Society of Australia.
Important findings have resulted from the analysis of over 8,000 crater timings reported by astronomers throughout the world, and recently these new data have been supplemented by image analysis of video records made of nine lunar eclipses recorded by video in Western Europe, South America and in Australia.
The most important new finding is that the oblateness of the umbral shadow cast onto the Moon from the upper atmosphere of the Earth is three times that previously thought by classical astronomy. Here the out-of-roundness, eccentricity or ellipticity of the Earth's atmosphere was thought to be equal to the shape of the solid Earth, or its Geoid - a value of 1 in 298.27, now lunar eclipse research has shown that this value is 1 in 102, that is 3 times greater as shown below from image analysis of video records of the 1990 February 9 lunar eclipse.
Computer analysis of images taken by CCD video cameras, show that the geometry of the Earth's upper atmosphere changes during each lunar eclipse analysed such that the recorded diameter is smaller when the Earth's shadow first covers the Moon's edge at first primary contact, increases at mid-eclipse and again reduces in size when the umbra begins to leave the Moon at fourth primary contact. One image analyst picture to determine this is shown below:
More recent computer predictions of the expected topocentric umbral geometry have been compared with image analysis measurements of the 1996 April 3-4, and the 1996 September 27 eclipses, where improved values in the dynamic change in umbral semi-diameter have been shown to vary around ± 0.2 degrees during each eclipse.