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Refractors, Newtonian reflectors and Catadioptrics
are the three main types of telescopes. All these
different types have the same purpose, but each
telescope design does it differently. Collecting
light and bringing it to a point of focus so it can be
magnified and examined with an eyepiece is their
goal.
Of the different types of telescopes the refractor
is the telescope most people think of when they
think of astronomy. This type of astronomy telescope
is easy to use and reliable due to the simplicity
of design. It requires little or no maintenance. Its
great for looking at the different types of lunar,
planetary, and binary stars.
Newtonians are a type of telescope, which is also
known as catoptrics. This type is different from
the other telescopes because it has the lowest
per inch of aperture compared to refractors and
Catadioptrics, because lenses are more expensive
to produce than mirrors, especially in medium
to large apertures. Newtonians deliver very bright
images and are low in optical aberrations.
Catadoptric telescopes are the most popular type
of instrument, with the most modern design,
marketed throughout the world in 3 1/2 and larger
apertures. Its very good for looking at different
planetary, lunar, and binary stars. If you like to
take photos with your telescope this type of
instrument is excellent for deep sky observing
or astrophotography with fast films or CCD's.
About the author:
Jeremy Hier makes it easy and quick to decide which telescope
is best for you by going to http://www.best-telescope-guide.com
What's The Difference Between Distance Learning And American Public Schools? John TiptonBefore distance learning and elearning, students in rural
school districts were often at a great disadvantage when it
came to subjects being offered. A small school district
sometimes didn't have the resources to attract teachers
that were in high demand.
Math, science and foreign language classes were often
limited because of this shortage. Today, distance learning
and elearning have changed the way school districts
determine class schedules, making many more opportunities
available to students.
Public schools have changed dramatically over the past
century and a great number of those changes can be put down
to two factors - state and federal mandates governing the
classes that must be offered and requirements for
graduation, and (of course) the ever-increasing world of
technology.
Computers have made the world a global neighborhood in
which anyone can instantly communicate with those from
another country, even if that country is half way around
the world. Language and time differences are virtually the
only barriers. This means that distance learning and
elearning are a part of the curriculum of many schools.
As schools began to connect to the Internet, the immediate
concern in most cases was how to regulate the use. The next
was how to best use the technology to benefit school
districts and students. Distance learning and elearning
became the way to provide options, especially in those
rural districts that couldn't meet state mandates.
Consider the situation of many smaller, rural schools. If
the school is required to offer a foreign language but
can't recruit a teacher, what should happen to that school?
Forced consolidations have been common in some states.
Students lost the benefits of schools in their own towns
and faced long bus rides to new districts.
With distance learning and elearning, more schools can meet
the state and federal mandates to offer specific classes.
Consider yet another situation. A smaller district has four
students who show great promise in their math studies and
it's quickly apparent that they could go well beyond the
normal math classes offered in high school.
There's no one on the teaching staff capable of teaching
those advanced concepts and it's financially impossible to
hire someone for that task alone. Distance learning or e-
earning could provide those classes.
Special needs children are another group to greatly benefit
from distance learning and elearning. While many issues can
only be dealt with between teacher and student, face-to-
face, there are many things that can be taught and learned
online.
Whether the subject of distance learning or elearning is a
foreign language or sign language, and whether the class or
courses are being offered to one student or the entire
student body, distance learning and elearning have become
an important tool for many public schools.
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Find out why distance learning lets anyone go back to
school. Discover what you need to look for in a distance
learning program, and what you should avoid. Click
http://www.distance-learning-exclusive.com/distance-learning-colleges.html
About the author:
John Tipton dropped out of school early, and worked boring
jobs for 20 years. Then he discovered 'distance learning'
and finally got the education he missed. After lots of
different courses at lots of different schools, Peter
shares his experience in this series of useful articles.
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