How far can I see with a telescope?
Pretty far. Usually this question is asked when comparing two
scopes, as in "can I see farther with this telescope?" A bigger scope will
show you more, but not necessarily farther. You don't really
need to see farther, though. With the unaided eye, you can see 2.8 million
light-years to the Andromeda Galaxy. Even a very small telescope can show
you an object called 3C273, a quasar in Virgo that is 3 billion light-years
distant. But most objects that are interesting to look at aren't that far
away. What you really want with a telescope is light-gathering power to
see fainter things, not farther things.
How much magnification do I need?
Magnification is not what is important with a telescope. The
main thing a telescope does is to gather lots of light to show you faint
objects. It does magnify, but how much it magnifies is not the most
crucial factor. Many of the objects astronomers look at are actually
pretty big in apparent size, but are very dim. For example, the Andromeda
Galaxy is six times the apparent size of the full moon. It takes up a very
large piece of sky, but is much fainter than the moon so is not so readily
visible. The same is true of most deep-sky objects (galaxies,
clusters, and nebulae). However, for the planets--which are bright but
appear small--more magnification is a good thing. There is still such a
thing as too much magnification, which will make the planet appear dim and
blurry, but you would typically use more power on the planets than deep-sky
objects. For example, 40-80x magnification is typical for deep-sky
observing, while 150-250x is common for viewing planets. See the
Understanding Magnification page for more
The most important thing to keep in mind is that
magnification is not a measure of how powerful a telescope is. This is
measured by the aperture (diameter) which determines the light-gathering power
of a telescope. In fact, a sure sign that a telescope is poor quality is
when it is advertised by magnification. Avoid any telescope that says
"650x" or any similar exaggerated claim.
Can I see color with a telescope?
The answer to this depends on what you are looking at. Bright
objects like stars and planets will show color. But faint objects like
nebulas will not normally show color. This is because of how the human eye
works. We can see color in bright things but not in dim things. In
low light levels, the eye sees using rods, which are cells sensitive to only
black and white. We only see color using the cone cells in the eye, which
are sensitive only to bright light. Cameras can capture the real color in
objects like nebulae by taking a long exposure which captures more light than
you eye can. However, subtle colors can sometimes be seen in brighter
deep-sky objects. Planetary nebulae, like the Ring Nebula in Lyra, show a
distinctive blue-green color. This is because they give off most of their
light at that wavelength, which also corresponds to the color the human eye is
most sensitive to in low light. But the reds and pinks of photographs are
almost never seen.
Note that the colors of planets are also subtle. We are
used to seeing NASA photos that are color-enhanced to bring out more detail.
The shadings on the planets are subtle, but are definitely visible upon close
observation. Remember to take time to observe closely and you will see the
tan shades of Saturn's rings and clouds, the reddish hue of Jupiter's cloud
belts, and the red and grey patterns on Mars.
What are the differences between a reflector and a refractor?
Reflecting telescopes use mirrors (which reflect light) while
refractors use glass lenses (which refract light). The first telescopes
were refractors, but reflectors have become more popular. In practical
terms, reflectors are usually cheaper to make, so you can get more telescope for
the money. Refractors give correct images making them useful for
terrestrial observations, while reflectors give inverted views. There are
other types of telescopes as well, but this is the basic differentiation that
beginners need to know when choosing a first telescope.
Is there any way to correct the upside-down image in a Newtonian?
The short answer: No. If you want to view terrestrial subjects
such as wildlife, you are better off with a refractor or Cassegrain-type
telescope. Newtonians give an inverted image, which is fine for looking
out into space where there is no up or down. In theory a prism could be
put into a Newtonian to correct the image, but in practice there is never enough
focus travel on a Newtonian to fit the prism into the light path. There
are some exceptions to this, but they are very rare, and often found only in
Can I take pictures with my telescope?
This depends on the type of telescope you have and the type of
picture you want to take. Just about any telescope can be used to
photograph the moon, although attaching a camera to some telescopes is
impractical. A telescope has to be heavy-duty enough to support the weight
of a camera, for one. Also, an adapter must be available to attach the
camera. Anything other than the moon becomes more difficult to photograph
and requires a more sophisticated telescope. Deep-sky objects in
particular are very faint and require a long exposure. This necessitates a
heavy mount with very accurate tracking capabilities. Figure, in general,
that a telescope capable of long-exposure deep-sky astrophotos will cost at
least $1500. Anything less might be good for lunar, planetary, and
terrestrial photographs, but not for deep-sky.
Is automatic tracking essential?
Only for photography. While it is very handy for observing,
especially when sharing the view with others, it is not essential. This is
why Dobsonian telescopes, which do not normally have automatic tracking, are
very popular for visual observers. For long-exposure photography, tracking
is a must-have. If you plan on sharing the view a group of people,
tracking is a very good thing to have, as the object will be kept centered
in the field of view while Earth rotates, allowing everyone to see without
someone having to adjust the telescope every 60 seconds or so.
Are binoculars a better way to begin learning the sky?
Beginners are often told to start with binoculars to learn the sky.
There are pros and cons to this advice. On the plus side, binoculars are
very portable and easy to use. They can also be used for other purposes
such as birdwatching or sporting events. This can help justify the initial
cost. However, it is often just as well to start with a telescope.
Finding objects with binoculars is not necessarily easier than with a telescope.
You will certainly see much more in a telescope than binoculars. What
often happens when someone starts with binoculars is that they immediately want
to see more and upgrade to a telescope anyway. A good pair of stargazing
binoculars can cost nearly as much as an entry-level telescope. Stars are
the most critical test for any optical system, so a cheap pair of binoculars
that looks okay during the day may give poor star images. The largest
binoculars will not show Saturn's rings, but even the smallest telescope will.
See the Binoculars page for more details.
What objects should I look at when I'm just getting started?
There are many good objects to see at any time of the year. The
planets and moon, of course, are great first targets and will be sure to impress
anyone looking through your new scope. They are also very easy to find.
Brighter deep-sky objects like the Orion Nebula are also perfect for getting
started because they are relatively easy to locate and show much detail.
See the Best Beginner's Objects page for a list
of things to see during every season.