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Science Blog ZINC PROJECTS

Saturn, Mars, Regulus, Moon alignment

Date: 08-Jul-08
Author: Andrew Yee

On 5 July 2008 Saturn, Mars, Regulus and a crescent Moon aligned in a straight line in the western twilight sky after sunset. Mars is the orange dot in between Saturn, the highest of the three dots in the image, and Regulus which is the brightest star in the constellation Leo (The Lion).

In this 10-second exposure the 3-day-old crescent Moon is overexposed. But its unlit side is also visible. This is called earthshine. The portion of the Moon that did not receive direct sunlight was at night. The lunar nightside, however, received illumination from reflected light of the daytime side of the Earth. The Moon received this "earthlight" illumination and then reflected it back toward Earth, thus allowing observers to see the faint outline of the rest of the Moon. If it sounds a little complicated, see a diagram in the link below.

Courtesy: Andrew Yee
(Click on image for larger version)

The photography site is Sunnyside Beach at the western side of Toronto, with Humber Bay separating the distant skyline of areas further west in the city.

Look closely at the image; practically no one on the beach paid attention to the celestial alignment. Everyone else appeared to look in the opposite direction. The reason is that the grand finale of the annual firework competition at Ontario Place, a tourist attraction east of the beach, was about to start.

Twenty minutes later the firework display began in the east. Jupiter appeared as a very bright dot well up in the southeastern sky at that time.

Courtesy: Andrew Yee
(Click on image for larger version)

Related link:

• Earthshine