actual questions heard at public star parties...
- How far can you see with that thing?
Farther than your mind or mine can imagine. Even traveling at 186,000 miles per second, the light arriving from other galaxies took millions of years ago to get here, so what we see is millions of years into the past. While star clusters and nebula may be a thousand times closer, even the Orion Nebula is still about 10 million billion miles away (1500 light years).
- How much does your telescope magnify?
(or; How much "power" does it have?)A typical amateur telescope magnifies about 50 to 200x. It depends on the eyepiece used and the focal length of primary mirror or objective lens. Could be more, could be less. What's more important than magnification, however, is the DIAMETER of the primary mirror or objective, for that is what determines how much LIGHT the telescope collects. Never buy a telescope by magnification ("power") alone.
- What's a light year?
A light year is a distance, not a time. It is the distance light travels in 1 year, or about 6 trillion miles. The nearest star is about 4 light years away, the nearest separate galaxy (outside our own) about 2 million.
- How old is the universe?
Current thinking is about 13 billion years since the big bang.
- How big is the universe?
That's a tough one. The simple answer, is that the observable universe is about 13 billion light years in radius. However, the prevailing theory is that the early universe expanded, for a brief time, at greater than the speed of light. Thus, there are volumes of space beyond which we can ever know about. This greater than light speed expansion is termed "inflation", and occured immediately after the big bang. Inflation theory correctly predicted the fluctuations in the cosmic microwave background radiation that has now actually been observed.
- Will the sun explode?
Far in the future, about 5 billion years, it may indeed "Nova", swelling up to enormous size, even engulfing the earth. There is also thought, however, that much before this, that gradual brightening of the sun will be enough to vaporize all the oceans on earth perhaps "only" a billion years from now.
- Do you believe in Aliens?
To know whether there is intelligent life elsewhere in the universe, is surely one of the most profound questions we can answer, yes or no.
- What's a good telescope to get?
Plan to spend about $250 before buying a new telescope. If you can't spend that much, get some binoculars. A 10x50 size can cost ony $50, and will give you great wide field views of star clusters, and even nebulae from a dark sky site.
For that first real telescope, it's hard to beat a 6" (mirror diameter) Dobsonian Reflector. These are available from a number of manufacturers for less than $250.
Another approach is to build your own telescope. Some amateurs grind and polish their own mirror to get the biggest telescope they can afford, and learn a lot about telescope operation in the process.
And many clubs (including NHAC) have loaner telescopes that members can borrow, to learn about the instruments before buying one.
Also see:
So you want to buy a telescope?
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