Two very different ways to explore the same night sky.
There are two types of telescopes being used tonight: Visual Telescopes and Smart Telescopes. They provide two very different ways to explore the night sky.
Please ask the astronomers about their telescopes — they will provide you with a wealth of information.
Some visual telescopes tonight are Schmidt-Cassegrain telescopes (SCTs). Light enters through a corrector lens at the front, reflects between two mirrors, and is focused into an eyepiece.
We typically also have a Dobsonian, which is another type of visual reflecting telescope. Light hits a large mirror, is reflected to a smaller mirror, and focused by the eyepiece near the top of the telescope. The Dobsonian is the largest scope at our star party, with a 12" main mirror. Many of the SCTs have 8" or 9.25" main mirrors.
When you look through the eyepiece of either, you are seeing light that actually came from the object. Light from the Moon takes about 1¼ seconds to reach your eye. For stars, nebulae, and galaxies, that light may have traveled for hundreds, thousands, or even millions of years before reaching your eye tonight.
Telescopes are commonly described by their aperture — the diameter of the main mirror or lens that gathers the light. Larger apertures gather more light and can reveal finer detail, which is part of why the Dobsonian's 12" mirror can pull in fainter, more detailed views than the 8" and 9.25" SCTs.
Smart telescopes for amateur astronomers are relatively new, although professional observatories have used computerized telescopes and electronic cameras for many years.
The smart telescopes tonight are refractors, using lenses rather than mirrors to gather and focus light. When initialized, they examine the stars around them to determine where they are pointed. Select an object, and the telescope can automatically locate and track it.
Smart telescopes are essentially telescopes combined with digital cameras and computers. Instead of looking through an eyepiece, you see the telescope's image on a tablet.
They take many short exposures and combine — or "stack" — them. As more images are stacked, faint objects become clearer and more detailed.
Their lenses are about 2 inches in diameter — much smaller than the visual telescopes. But a camera can collect light over time, revealing faint details that your eye cannot see through an eyepiece.
Cameras can also reveal the colors of stars, nebulae, and galaxies. In very low light, your eyes rely mainly on rods, which do not detect color — that's why most faint objects seen through a visual telescope appear in shades of gray. A smart telescope's camera can collect enough light to reveal their colors.