ELi ON EARTH: Night Light Pollution

Above: Spartan Stadium’s scoreboard this past Saturday night, as seen from the City Center I parking garage.

This spring, Venus has been very bright in the western sky from twilight until about 11:45 pm, when it sets. Venus is usually the brightest object in the night sky except for the moon, and for the last couple of weeks even the moon has not been in competition. For the last week or so, the moon has not risen (in the east) until after Venus has set (in the west). Eli has covered Venus before.

Being bright and prominent in the sky makes Venus useful for finding more difficult-to-see objects like Uranus, and this week Venus has been quite close to another interesting celestial feature, the Pleiades. The Pleiades are a group of young, hot stars about 400 light-years from earth and have been a few degrees north of Venus this week.

In many places the Pleiades are visible with the naked eye, and many cultures have stories and myths to explain this group of bright stars. As an example, the Japanese name for the Pleiades is Subaru, and the car company took that name and the star cluster as its logo.

While the Pleiades are visible to the naked eye in most places and sometimes in East Lansing, they were not visible in East Lansing’s sky due to light pollution this Saturday night, April 11, 2015. Spartan Stadium was the major problem that night. The scoreboard lit up the night sky including the trees in my backyard almost a mile away. Below is a picture of the scoreboard and stadium from the City Center One parking ramp.

East Lansing residents have to conform to zoning ordinances governing outdoor lighting to reduce light pollution. You can read the East Lansing exterior lighting ordinance Section 50-155 here. Michigan State University is not covered by East Lansing zoning law.

Beyond the challenge to local astronomers, light pollution is a problem for migrating birds. You can read about communities with “Lights Out” programs here.

While the Pleiades were not visible with the naked eye on the 11^th, their proximity to Venus made it possible to find them with a digital camera. With a tripod to hold the camera steady, it is possible to take a long exposure picture that captures Venus and the Pleiades. This picture (below) was taken on a standard digital single lens reflex camera (Canon Rebel EOS T3) on maximum sensitivity (ISO 6400) for five seconds. The Pleiades are shaped a little like the Big or Little Dipper and are shown just to the right of Venus as seen through the trees of my backyard.