Sommers-Bausch Observatory - University of Colorado


Harvest Moon Lunar Eclipse


The commentary below is what we'd hoped to see - but in actuality, this is what was really seen due to clouds ...


September's "harvest moon" -- the full moon closest to the first day of autumn -- will be in total eclipse on Thursday, Sept. 26, an occasion for the University of Colorado at Boulder to hold a special open house at the Sommers-Bausch Observatory.

The free open house will begin at 7 p.m. and continue until about 10:35 p.m. when the eclipse will be over. Viewers may see the eclipse from the observation deck of the Sommers-Bausch Observatory and from parking lot 418 west of the Coors Events/Conference Center on the CU-Boulder campus.

The 18-inch and 16-inch telescopes will be available for public viewing, and additional telescopes will be set up in the parking lot. The observatory staff will be on hand to answer questions about eclipses and other celestial events.

Observers will notice a change in the moon's appearance as soon as it rises at 6:39 p.m. and should easily see the darkening by 7 p.m. The moon will be fully immersed in the Earth's shadow, cast by the sun, at 8:25 p.m., where it will remain for just over an hour.

Mid-totality will be at 8:51 p.m. and the last portion of the moon will completely emerge from the umbral shadow at 10:35 p.m.

These times are predicted for the Boulder area and will vary by one minute or less for other parts of Colorado.

Astronomers expect a spectacular show, weather permitting, because the planet Saturn will be only about four times the moon's diameter from the moon during the eclipse.

The 6th magnitude star designated HD1367 will appear to skim the northern edge of the moon about the time of mid-totality at 8:51 p.m. Observers with telescopes near Castle Rock, Colo., should be able to see the star peep in and out from behind lunar craters, called a "grazing occulation."

A lunar eclipse can happen only during the full phase of the moon, when it is on the opposite side of the earth from the sun. Although full moons occur about once a month, lunar eclipses, either partial or total, can only occur about once every six months. Occasionally, lunar eclipses occur on consecutive full moons only one month apart.

A partical eclipse (90 percent) will be March 23, 1997, but this month's event will be the last total (100 percent) eclipse of the century observable from Colorado. The next total lunar eclipse will be Jan. 20, 2000.

"While solar and lunar eclipses occur with equal frequency, eclipses of the moon can be observed by many more people, so any spot on earth usually experiences a lunar eclipse every two to three years," said astronomer Katy Garmany, director of Sommers-Bausch Observatory and FiskePlanetarium.

"Astronomers have wrung most of the interesting scientific observations from these events, but lunar eclipses are beautiful chances for the public to observe the moon and sky and learn more about the motion of our nearest neighbor in space," said Garmany.

Fiske Planetarium is located on the corner of Regent Drive and Kittredge Loop on the CU-Boulder campus. Sommers-Bausch Observatory is 100 feet east of the planetarium. Visitor parking is available in metered lot 306 (free after 5 p.m.) on the south side of Regent Drive or lot 330 on the north side.

For information about programs at Fiske Planetarium and Sommers-Bausch Observatory call (303) 492-5001 for a recorded announcement or (303) 492-5002 to speak to the staff.