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Astronomical Observatory: Special Open House

Total Lunar Eclipse, Sunday September 27

The Calvin College observatory had a special open house September 27 for public viewing of a total lunar eclipse. The observatory opened at 8:30 pm EDT while the sky was still completely clouded. The forecast was for clear skies approaching from the west, although the timing was a little ambiguous. About 170 visitors gathered in the dome and on the observing deck awaiting a glimpse through the clouds. The Moon entered the umbra of the Earth at 9:07 and reached totality by 10:11. The view from the deck remained stubbornly overcast.

Clouds above the Science Building dome (photo by Prof. Jason Smolinski).

Fortunately, by this time the Moon had risen at the location of Calvin's remote observatory in Rehoboth, New Mexico. We took a series of images as the Moon entered totality using the guide camera on that telescope.

Lunar Eclipse
Sequence of 10 images as the Moon approached totality taken with the ST-i camera mounted on the guide scope (photos by Prof. Larry Molnar). The position of the Earth's shadow is stationary as the Moon drifts into it.

In the middle of totality, still waiting for the sky to clear, we noted the sun-moon dial of our historic Botjes Planetarium (completed in 1868) accurately showed the details of the eclipse: 1) The Moon was exactly opposite the Sun, indicating full phase; 2) Both objects were within a degree of the line-of-nodes dial, indicating a total lunar eclipse; and 3) The Moon was on top of the "perigee" dial, indicating a supermoon.

The sun-moon dial of the Botjes planetarium at 10:50 (photo by Prof. Larry Molnar).

Just as totality ended at 11:23, the sky in Grand Rapids cleared. For those that remained to this point, a beautiful view of the rosy Moon was seen through the telescope, through binoculars, and simply looking up from the observing deck. The stages of egress soon followed.

Lunar Eclipse

Lunar eclipse at 11:35 pm EDT, just 12 minutes past the end of totality (photo by Prof. Jason Smolinski).

Posted September 28, 2015 by L. Molnar.


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