9
THE ALTAZIMUTH MOUNT
The NG70CA telescope is fitted with an altazimuth mount. “Alt” refers to altitude, the
vertical movement of the telescope, while “azimuth” refers to the horizontal movement.
ABOUT MAGNIFICATION
The magnification power of a telescope indicates how much an image is enlarged or
how big and close it appears to the viewer. The focal length of the eyepiece, combined
with the focal length of the telescope, determines the magnification power. To calculate
the power of your telescope with any particular eyepiece, simply divide the focal length
of the telescope (700 mm) by the focal length of the eyepiece (indicated in “mm” on the
eyepiece collar).
Example: 700-mm focal length (tube) = 56X magnification power
12.5-mm focal length (eyepiece)
The 3X Barlow lens and interchangeable eyepieces provide the following magnification
values:
Eyepiece Power Power With 3X Barlow Lens
25 mm
28X 84X
12.5 mm
56X 168X
4 mm
175X 525X
The level of magnification required depends on the object being observed. Optimal
performance is obtained if the magnification is typically not more than about 30X for
every 10 mm of objective lens diameter. Magnification of around 175X or less is ideal
for a telescope with a 60-mm diameter objective lens and is best for observing most
celestial objects. A lower magnification power and a wider field of view are advisable for
observing galaxies and nebulae. The highest magnification power should be used for
highly detailed observations of the moon, Jupiter, Saturn, or any object that is quite
bright.
The highest magnification power of the Barlow lens/4-mm eyepiece combination should
only be used for large or bright objects such as the moon and the brightest planets.
USING YOUR TELESCOPE FOR ASTRONOMICAL VIEWING
1) Take your telescope outside. Viewing objects through closed or open windows is not
recommended. Your view can be distorted by reflections in the glass of a closed
window or by air currents of differing temperatures passing through an open window.
2) Let your telescope adjust to the outside temperature. Your telescope will perform
much better if the temperature of the lenses and the air inside the tube are the same
