Introduction

Several lunar eclipses have been imaged by kurita@private.email.ne.jp and some of these images have been analysed to see if change occurred in the umbral semi-diameter during the period of each lunar eclipse.

Here the image analysis software measured an umbral semi-diameter of 0.687 degrees, with a calibrated semi-diameter of the moon (top left in the picture) of 0.25 degrees. The distance between the centre of the moon and umbra is shown as 0.772 degrees.

Here the image analysis software measured an umbral semi-diameter of 0.622 degrees from the left images, with a calibrated semi-diameter of the moon (centre in the picture) of 0.25 degrees. The distance between the centres of the eclipsed moon and umbra is shown as 0.063 degrees.

Here the image analysis software measured an umbral semi-diameter of 0.633 degrees at the right images, with a calibrated semi-diameter of the moon (centre in the picture) of 0.25 degrees. The distance between the centres of the eclipsed moon and umbra is shown as 0.064 degrees.

Other sequenced images were also measured for the lunar eclipses of 2000 July 16 and 1990 August 6, the first eclipse gave umbral semi-diameters as follows:

At 21 hours 30 minutes (UT) the measured umbral semi-diameter (Fi) was 0.580 degrees, at 21:45 Fi = 0.515, at 23:59 Fi = 0.291, at 24:15 Fi = 0.241 and at 24:45 Fi = 0.304, with the semi-diameter of each imaged moon recalibrated at 0.25 degrees. The data for this total eclipse and for the partial eclipse of 1990 August 6, measured in a similar way are shown in the graphs below,

If the location of the observer is provided, then the expected topocentric umbral semi-diameter for each eclipse from that site can be computed. A comparison can then be made with the above measures to see if any substantial change in the umbral geometry was observed.