On October 28th, the Earth will pass between the Moon and the Sun. Consequently, the shadow cast by the Earth will partially eclipse the Moon.
The Earth’s shadow has two components, a component with a larger radius – the penumbra, and another with a smaller radius- the umbra. On this day, the Moon will cross the Earth’s penumbra and intercept a small portion of the umbra, hence the designation of partial eclipse.
Eclipse data for Monsaraz. Time and altitude of the Moon in the sky:
| Local Time | Altitude (º) | |
| Penumbral eclipse start: | 19h01 | 6.5º |
| Umbral eclipse start: | 20h35 | 23.4º |
| Umbral eclipse maximum: | 21h14 | 31.7º |
| Umbral eclipse end: | 21h52 | 39.1º |
| Penumbral eclipse end: | 23h26 | 55.5º |
What can we see? The Moon should reach a relative magnitude of +0.12, which means, it will have an accumulated luminosity comparable to that of the star Vega, which has a relative magnitude of +0.03. For comparison, the Sun has a relative magnitude of -26.74 and the full (non-eclipsed) Moon of 12.6! During the umbral phase of the eclipse, it will be possible to distinguish a region of reddish tone due to Rayleigh Scattering.
For more information regarding our sessions see our Astronomical Observations page.