Telescope image

All Reflecor telescope images are due
"cbreez" wrote in message
...
Are all telescope images inverted ? Is there a way to change that like put
on a eyepeice that corrects the image ?

Inversion is an intergrate design due the optical charateristics. This
applies only to reflective telescopes. Since reflector are used primarily
for so-called deep space astronomy, this is not really a problem. On the
other hand. a refractor which is normally used for terrestrial viewing gives
an upright image. So if you are going to look for nebulae and distant
galaxies the reflector is the way to go. The refractor is the telescope for
terrestrial and local solar system objects. To answer your question, yes it
is possible to purchase an "upright" lens for a reflector, but if you can
find one of high quality it can prove to be prohibitively expensive. For
really expert advice you might try www.telescope.com this is Orion
Telescope's Home Page
--
Wayne Thompson
Napa,CA

In message k.net,
Wayne Thompson writes
All Reflecor telescope images are due
"cbreez" wrote in message
...
Are all telescope images inverted ? Is there a way to change that like put
on a eyepeice that corrects the image ?

Inversion is an intergrate design due the optical charateristics. This
applies only to reflective telescopes. Since reflector are used primarily
for so-called deep space astronomy, this is not really a problem. On the
other hand. a refractor which is normally used for terrestrial viewing gives
an upright image.

Minor correction, but an "astronomical" refractor will give an inverted
image with a normal eyepiece. You can buy a "terrestrial" eyepiece which
gives a right-way-up image, and a spotting-scope which is bought for
terrestrial use - bird-watching or whatever - will have one already
fitted.
--
Greetings from Airstrip One!

Mail to jsilverlight AT merseia.fsnet.co.uk is welcome.
Or visit Jonathan's Space Place http:\\www.merseia.fsnet.co.uk

Hi there. You posted:

Inversion is an intergrate design due the optical charateristics. This
applies only to reflective telescopes. Since reflector are used primarily
for so-called deep space astronomy, this is not really a problem. On the
other hand. a refractor which is normally used for terrestrial viewing gives
an upright image.

Well, I'm afraid that this might be a little misleading. *All*
astronomical telescopes will generally invert the image (ie: make it
"upside-down") unless an additional set of optics like an image erector
or a special 45 degree Amici prism erecting diagonal is used. If a
90-degree star diagonal is used in a refractor, the image may or may not
be upright depending on the orientation of the diagonal and the person's
head. If the telescope is used terrestrially and the star
diagonal/eyepiece is pointed straight up (ie: the person is looking
straight down with the top of his head in the direction the telescope is
pointed) the image should be upright. However, in this case, a regular
90 degree star diagonal will also *reverse* the image (left to right) so
it will look like that seen in a flat mirror. Reflecting telescopes
like a simple Newtonian also invert the image, but they do *not* reverse
it, since they use two reflections to create the image. Cassegrain
designs, like refractors, are often used with 90-degree star diagonals
which will also result in a reversed image. With some smaller
reflectors, it is possible to stand at an odd angle with your head
oriented so that the image is "almost" upright, but with larger ones,
the tube gets in the way. In any event, since there is really no "up"
or "down" in space, the inversion caused by an astronomical telescope is
a minor inconvenience.

So if you are going to look for nebulae and distant
galaxies the reflector is the way to go. The refractor is the telescope for
terrestrial and local solar system objects.

The refractor can also be successfully used for nebulae and distant
galaxies. In fact, the small to moderate-sized "rich-field" refractors
can offer outstanding views of star clusters and nebulae. The key for
deep-sky objects here is *aperture*. The greater the aperture, the more
you will tend to see. With refractors, again, cost of large apertures
becomes prohibitive, so the reflector gives the user a little more "bang
for the buck". Reflectors can also offer good views of solar system
objects, so the solar system isn't just the exclusive purview of the
refractor. Clear skies to you.
--
David W. Knisely
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/

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