Star Gazing: Open House Planned At Behlen Observatory
By Lisa Brichacek - Wahoo Newspaper Staff Reporter
MEAD - Peering into the darkness, the telescope at the Behlen Observatory brings space closer to earth.
The public will get an opportunity to see that telescope as well as other things at the observatory near Mead during an open house on Friday, Oct. 23. from 7 to 10 p.m.
The open house gives the public a taste of what an astronomer sees and does, said Dr. Kevin Lee, Behlen Observatory Coordinator and University of Nebraska-Lincoln physics/astronomy lecturer.
Work at the observatory includes the study of stars.
Studying the stars is a little different than some people might think, Lee said.
“The movies have that stereotype of an astronomer sitting in front of a telescope.”
With advancing technology, that stereotype no longer accurately depicts people in this scientific field.
“Very, very few astronomers sit in front of a telescope. Most sit in front of a computer screen,” Lee said.
That is true too at the Behlen Observatory.
“The telescope spins all by itself.”
He said it can do this because it is automated and is controlled by a series of coordinated points programmed into a computer.
The computer tells the telescope where to aim in order to find the stars that he wants to study.
The Behlen telescope is not totally automated though. Lee said an astronomer still needs to be present to make sure the telescope is behaving properly and not going off course.
“It’s automated to the point that you can read a book. It requires human intervention on a scale of about every hour or so.”
He said one of the things that can happen is that the telescope can “run”. If this happens, it does not stay on the coordinates that are programmed, but rather it freely moves around.
“Sometimes it will run all the way down to the horizon.”
If this happens, Lee said, an alarm will sound so that the astronomers know human intervention is needed immediately.
Another thing sometimes requires human intervention is the dome that houses the telescope and provides an opening for its skyward viewing. “The dome is the most onere thing,” Lee said.
The dome moves with the movement of the telescope.
Lee said it has to be periodically checked to see if it is moving properly.
There is also the possibility of a computer crash. Lee said the computer needs to be checked periodically through the night.
Those are the common things that Lee adjusts during his night shift at the observatory. He said even though sometimes it can be fairly problem free, the astronomers at Behlen still need to stay on watch.
“Then something new happens that’s never happened before.”
An example of this occurred one night when he was setting up for an observation. He said the dome, usually controlled electrically, could not be opened because of a technical problem.
Lee said he then had to use a long rod and open the dome door manually.
Opening the dome is just one task that Lee has to do before the telescope can be used for his star research.
In order to record the star observations, an electronic camera takes pictures of the observations.
Lee said the telescope’s camera operates similarly to a home video camcorder. He said they are both referred to as a CCD, or charged coupled device.
There is a difference though.
Behlen Observatory’s 30-inch telescope brings back reflections from space, not just across the room.
Lee said the distance that a telescope can see into space relates to its Light Gathering Power, which can be determined through a mathematical equation using the reflectors’ diameter.
He said it is similar to the distance an individual can see with the naked eye. The size of the lens and the amount of light gathered in by that lens helps determines the area that is seen.
“Our telescope gathers approximately 23,000 times as much light as a typical person’s eye.”
Another difference is that a cooling process has to be done at the observatory before star studies can begin.
Lee said in order to get clear, crisp pictures, the camera mechanism must be cooled.
Liquid nitrogen is used as a cooling agent. A tank of liquid nitrogen is connected to the bottom of the telescope and allowed to boil. As it boils, Lee said the liquid nitrogen cools it to a temperature of minus 100 degrees Celsius.
The next set up step prior to telescope observations is getting the computer programmed.
The computer room is on the second floor of the Behlen Observatory, one level below the dome room.
Lee said since the telescope is driven by the computer, the computer must be told where to take the telescope.
To do this, Lee “cues” the computer with such numbers as ascension and degree angles.
“We also program how long of exposure time is needed (for the camera to take a picture) and when to stop observing, like at sunrise.”
All of this set up usually takes a little less than an hour and a half, Lee said.
With the set up done though, Lee and any other astronomer using the Behlen Observatory waits, with periodic checks, through the night as the telescope does the work of collecting data.
That data comes in the form of the pictures that are taken. He said those pictures can then be read and stored by the computer so that the observations can be further studied.
“The picture is just numbers to the computer. The computer extracts its information from numbers.”
Currently, two UNL astronomer are making observations at the Behlen Observatory. In addition to Lee, Dr. Ed Schmidt also studies the stars. Schmidt, is Observatory Director and also serves as an Associate Dean of UN-L’s College of Arts and Sciences.
Schmidt said the observatory is a laboratory for the field of astrophysics.
“We study the physics that govern inside a star and (the observatory) helps us for that.”
Lee said the type of information gathered for stars includes such things as brightness and size.
He said by comparing a star to itself over time as well as other stars, different things about its age and development can be learned.
For example, astronomers know that as a star ages it gets bigger.
“Smaller stars can be old stars, but big ones can’t. Big ones just don’t live very long.”
Lee said types of stars are also studied. There are variable, or twinkling stars, and constant stars.
He said data is collected on how bright the star is.
“We’re very interested in time as well and we’ll look at how brightness changes over time.”
During the course of a one night session, Lee said about 500 to 600 comparison observations can be made and recorded.
Pictures are not the only way to view the stars at the observatory though.
Lee said a flip mirror at the base of the telescope will allow the public to see the stars during the open house next week.
“With the flip mirror, one position it takes pictures, the other position they can look through it.”
In addition to the stars and a crescent moon, two planetary systems will also be viewable on Oct. 23.
Jupiter, its moons and Saturn will be visible.
Saturn will be at opposition, or in the opposite direction in the sky to the sun. According to Lee, this is the best time for most Earth-based observations of the ringed planet.
Other attraction during the open house will include slide shows by physics and astronomy UN-L faculty and graduate students.
Tentatively scheduled talks include the topics of “Quasars,” “What Astronomers Really Do” and the “Europa Cryobot.”
Lee said a demonstration on telescope optics is also planned.
He said this will give open house participants a chance to see what’s inside of a telescope.
Tom Koch will have several optical benches set up that will allow people to see how light travels through a telescope.
Since telescope viewing is dependent on clear skies, Lee said there is a possibility that the open house could be cancelled or postponed. In order for that to happen, he said, it would have to be really cloudy though.
“If it is raining or completely overcast than we’d encourage them to stay home.”
Otherwise, the public is welcome to attend the free of charge event.
Schmidt said the open houses were started as there were many inquires about the observatory and that interest has continued.
The Behlen Observatory was dedicated in April, 1993. Plans for the new observatory began in 1971.
The observatory is located in a former Nebraska Ordnance Plant building known as a “change house.”
The upper levels of the change house were remodeled to accommodate the needs of the telescope astronomers and include a public viewing room and classrooms.
The first floor, used as a bomb shelter in the building’s earlier life, was not changed at the time of remodeling.
Directions to the Behlen Observatory from Mead are as follows.
Follow Spur 78F, County Road 10, about five miles to County Road H. Turn left on H and continue about two miles to County Road Eight. Turn left on Eight and go about .7 miles north to the observatory.
Back to the Behlen Observatory HomePage