The level of magnification required depends on the object being observed. Optimal performance is obtained if the magnification is typically not more than appromiately 30X for every 10 mm of objective lens diameter. Magnification of around 265X or less is ideal for a telescope with a 90-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 the observation of galaxies and nebulae. The highest magnification power should be used for highly detailed observations of the moon, Jupiter and Saturn or any object that is quite bright.

The highest magnification power of the Barlow lens/9-mm eyepiece combination should only be used for large or bright objects such as the moon and the brightest planets.

We recommend that you begin all observation sessions with the 25-mm eyepiece alone. Then if more viewing power is desired you can either change the eyepiece, add the 3X Barlow lens, or do both. Be aware that as well as brightness being decreased there will come a point when image detail is also lessened. This is further impacted by air pollution, light pollution, and upper-air turbulence. Lower magnification powers lessen these effects.

A common mistake made by many beginners is to start an observation session by placing the high-power 9-mm eyepiece and the 3X Barlow lens in the telescope at the same time. This is an exremely high power, dim configuration that “sees” only a very small portion of sky and is therefore very difficult to aim.

USING YOUR TELESCOPE FOR ASTRONOMICAL VIEWING

1)Take your telescope outside. We do not recommend viewing objects through closed or open windows. 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 as the outside temperature. It may take up to 60 minutes to equalize the temperatures when the difference in temperatures is extreme.

3)Find a location far from glaring light. If you live in a large town or city, your viewing will probably improve the farther you move away from the city lights. The sky glow of a town or city can dramatically reduce the telescope’s performance and viewing capabilities.

4)Remove the round plastic dust cover (lens cap) from the front of your telescope.

5)Begin your viewing session by using the 25-mm eyepiece by itself. It will give you the widest angle and the brightest, sharpest views.

11

Page 10 Page 12
Page 11
Image 11
National Geographic NG90EQ owner manual Using Your Telescope for Astronomical Viewing
Page 10 Page 12

NG90EQ specifications

The National Geographic NG90EQ is a premium-quality, fully-equipped equatorial telescope that provides amateur astronomers and enthusiasts with an exceptional viewing experience. This powerful telescope is ideal for both planetary observation and deep-sky tracking, making it a versatile addition to any stargazer's collection.

One of the standout features of the NG90EQ is its impressive 90mm aperture. This large lens collects ample light, allowing for bright and detailed images of celestial bodies. With a focal length of 900mm, the telescope offers a focal ratio of f/10, which is well-suited for high-magnification observation. This design ensures that users can easily spot planets like Jupiter and Saturn, as well as a variety of stars and nebulae.

The NG90EQ is equipped with an equatorial mount, an essential component for tracking celestial objects as they move across the night sky. This mount allows users to precisely align the telescope with the North Star, simplifying the process of finding and following planets and stars. The included setting circles further assist in locating astronomical objects, making it easier for newcomers to explore the night sky.

Another notable characteristic of the NG90EQ is its user-friendly design. The telescope features an adjustable, ergonomic tripod that provides stability and supports easy height adjustment. With an optical finderscope, users can quickly locate objects before zooming in with the main telescope. The scope also includes high-quality eyepieces, offering multiple magnification options for varied viewing experiences.

Durability is a key aspect of the NG90EQ, as it is built with robust materials that withstand regular use. Its compact design makes it portable, perfect for taking to dark sky locations away from city lights. The telescope's ease of assembly means that novice astronomers can set it up in a matter of minutes, encouraging exploration and learning.

In summary, the National Geographic NG90EQ telescope stands out due to its excellent optical performance, user-friendly features, and sturdy construction. With its equatorial mount and quality optics, this telescope is perfect for discovering the wonders of the universe, making it a fantastic choice for both beginners and seasoned astronomers alike.
Top Page Image Contents