Telescope Tour (Cloudy Night Program)
Many times during the year the Observatory is unable to present the scheduled program due to the weather. If it is clear enough to see some objects (i.e., planets or bright stars) through the telescope we generally look at those objects, explaining to people the reason for the change. If it is too cloudy to see anything, we show people the telescope and explain how it works. Of course all of the exhibits are available for people to use on these evenings, except Star Games (outside telescopes and binoculars) when it is raining or snowing.
The following items are usually discussed when visitors are shown the telescope:
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The main telescope has a 16-inch mirror in it.
Light enters the telescope at the top, strikes the main mirror.
The light is reflected back to the top of the tube where it strikes the secondary mirror.
The light travels back down the tube (a 3rd time), passes through the hole in the main mirror, and we look through the bottom of the telescope.
(It has a focal length of approx. 5490mm, and a photographic speed of f/13.5) -
The smaller white telescope attached to the primary scope is a 6-inch refractor telescope.
It uses lenses instead of a mirror to collect light and bring it to the focal point where an eye-piece can magnify the image.
(It has a focal length of 1200mm, and a photographic speed of f/7.9) -
The telescope is mounted in a rather strange way so that it can easily follow an object as it moves across the sky.
(German Equatorial mounting)
Move the telescope down so that everyone can look at the mirror from the observing ladder (Dust Cap removal position).
You can also have people looking through the telescope from the bottom while someone is looking at the mirror.
(Be sure to remove any eyepiece from the telescope first.)
The person looking at the mirror should see the other person's eye in the center of the 16-inch mirror.
FAQ
How big is the telescope?
The telescope is a 16-inch reflecting telescope. That means the mirror in the telescope is 16 inches across. It gathers about 5000 times more light than our eyes do.
How powerful is the telescope?
When astronomers talk about power, they talk about light gathering power. This telescope, with its 16-inch mirror, gathers about 5000 times more light than our eyes do. Now, once we have this extra light we can magnify things. This telescope can magnify an object between 80 and 500 times. The highest magnifications can be used only when the atmosphere is very steady.
How do you move the telescope?
The telescope can be moved a few different ways. The most direct is to press buttons on the hand paddle which tells the computer which direction to move the telescope. We can also select an object in the sky or enter its coordinates (right ascencsion and declination) using the computer and then have the computer move the telescope to that location.
Should I take my glasses off when I look through the telescope?
Some people see things better with their glasses, while others see better without them. Tell people to try looking through the telescope both with their glasses on and with them off to see which way works best for them.
How do I focus the telescope?
The telescope should be focused so you shouldn't have to refocus it. (We discourage people from focusing the telescope so that it can remain focused for others. If someone does refocus it, make sure you check the focus before the next person looks.) The fuzziness or unfocused image that you see is often caused by the atmosphere.