Hello Arild,

> > - The second case is the visual work at the eyepiece. Normally one
> > would prefer an "Inverted" view and "Alt/Az (zenith up)" here. This is
> > the case when you are standing or sitting behind your telescope
> > without a diagonal (refractor, SC telescopes) and your eyes are
> > parallel to the horizon. With a newtonian reflector you have to choose
> > "Mirror image E/W".

sorry, my fault. Arild is right. A newtonian has also 2 reflections and
therefore you have to use the setting "Chart inverted" which is the
same by the way as "Chart uninverted" AND a rotation of 180 deg.

> Either I'm reading this paragraph all wrong, or Bernd is mixing something. Or
> perhaps it is a confusion of wording. Nevertheless, a newtonian will rotate
> your field of view by 180 degrees. That is South is up, East is to the right. In
> a SCT w/diagonal or a refractor w/diagonal (odd number of reflections), North is
> always "up", but East is to the right. Ie. the image is mirror reversed. That's
> why using a printed chart like Uranometria is simpler with a newt than with a
> SCT w/diagonal, because you may just turn the atlas upside down.
>
> So, just follow Bernd's explanation above, but exchange the types of telescopes,
> and you should be all set :)

Clear skies
Bernd


Bernd Brinkmann
Herne, Germany

http://homepage.ruhr-uni-bochum.de/Bernd.A.Brinkmann/index.html