Venus and the Pleiades on April 12, 2015


Venus is just over 2° from the Pleiades star cluster, while the V-shaped Hyades star cluster, which makes up much of the constellation Taurus, is to the left of Venus in this image. This image taken after sunset over the Ottawa River on a pleasant spring night on April 12, 2015.

Shining at magnitude -4.1 for most of the month, Venus is easy to find high above the western horizon as the Sun goes down. It outshines every object in the sky except for the Sun and Moon.

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A Near-Perfect Einstein Ring Imaged by ALMA

ALMA image of the gravitationally lensed galaxy SDP.81.

The Atacama Large Millimeter Array (ALMA) is fast becoming my favorite telescope. New results and observations are coming out as the array ramps up its technical capabilities, and this week the observatory released new images including a dazzling example of a nearly perfect Einstein ring of an active star-forming galaxy from the early universe. An Einstein ring is caused when the gravity of a massive foreground galaxy bends the light of the more distant galaxy. The background and foreground galaxy must be nearly perfectly aligned to form this symmetric shape.

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The Sky This Month – April 2015

Lunar Eclipse4 April 2015. Full Moon, 13:05 UT. (The “Pink Moon”, “Egg Moon”, or “Grass Moon”).

4 April. A brief lunar eclipse occurs near today’s Full Moon just two weeks after last month’s total solar eclipse. Many lunar eclipses last an hour or more, but this one is unusually short. It lasts just under five minutes, from 11:58 UT to just past 12:02 UT. Observers in the eastern half of Australia and all of New Zealand and Hawaii can see the entire eclipse. In western North America, the total eclipse will be visible in the pre-dawn sky, but the Moon will set before the eclipse ends. Observers in eastern North America and most of South America will see the Moon set before the eclipse reaches totality.

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