Choosing the right eyepieces is important, but beginners tend to think the
most expensive is best. However,
each type of eyepiece has its own use. There are
different designs and lenses for different views. Buying eyepieces which suit
your own viewing is important. So, knowing what you want to observe is important.
In most cases, beginners should have two or three at most. This simple guide will
tell you about the different eyepieces and costs involved.
For general use, Orthoscopic lenses have been considered the best. Using four
elements and having a 45 degree field of view, they are excellent for viewing
planets. A lens of this type will set you back by $40
to $100.
Kellner is also a good general purpose lens and one of the cheapest at just $30
to $50. It drawback, though, is its 3 element design limiting the viewing range to 40 to
45 degrees.
T
he Ramsden and Huygenien have a two element design with a limited field of view,
but are good for observing the sun. They are also the cheapest lenses costing
just $25 to $40.
The most popular are Plossl lenses. With four or five elements it has a wider
field of view than a Orthoscopic lens, ranging from 50-52 degrees. Though
they are
more expensive costing between $50 and $150.
Barlow lenses double or triple the magnification of your eyepiece, but cost
between $60 and $100. Erfles are not as popular as they were but offer a field
of view of between 60 and 65 degrees having 6 elements. They run between $75 and
$150.
Televue has come up with a rival to this there six element Panoptic has a 67
degree field of view but costs between $200 and $400. The seven or eight element
Naglers has a 82 degree field of view and is cheaper at $175 and $425. Pentax
also makes a seven element lens, the SMC-XL, that costs about $250 and can
possibly exceed the Televue in performance.