National Geographic 70mm Refractor Telescope Instruction Manual

1. Introduction

Thank you for choosing the National Geographic 70mm Refractor Telescope. This instrument is designed to provide clear views of celestial objects such as the Moon, planets, and brighter deep-sky objects, as well as terrestrial observations. This manual will guide you through the assembly, operation, and maintenance of your telescope to ensure an optimal viewing experience.

2. Safety Information

• WARNING: NEVER look directly at the Sun through your telescope or its finder scope without a professionally manufactured solar filter. Permanent and irreversible eye damage, including blindness, can result.
• Always supervise children when using the telescope.
• Handle optical components with care to avoid scratches or damage.
• Ensure the tripod is stable on a level surface before attaching the telescope.

3. Parts Overview

Familiarize yourself with the components of your telescope. Refer to the diagram below for identification.

Figure 3.1: Telescope Parts Diagram
This image illustrates the various components of the telescope, clearly labeled for easy identification. Key parts include the 70mm Objective Lens, Pan-Tilt Alt-Azimuth Mount, Tripod with Accessory Tray, Optical Tube Assembly (OTA) with Dew Shield, Focus Wheel, Diagonal, 1.25" Eyepieces (9.7mm and 26mm), 2x Barlow Lens, Red Dot Viewfinder, and Smartphone Adapter.

• 70mm Objective Lens: The main lens that gathers light.
• Pan-Tilt Alt-Azimuth Mount: Allows movement of the telescope horizontally and vertically.
• Tripod with Accessory Tray: Provides a stable base and a convenient place for eyepieces.
• Optical Tube Assembly (OTA) with Dew Shield: The main body of the telescope, protecting the objective lens.
• Focus Wheel: Used to adjust the focus for a clear image.
• Diagonal: A mirror that reflects the light 90 degrees, providing a comfortable viewing angle and an upright, but laterally reversed, image.
• 1.25" Eyepieces (9.7mm and 26mm): Interchangeable lenses that determine magnification.
• 2x Barlow Lens: Doubles the magnification of any eyepiece used with it.
• Red Dot Viewfinder: A non-magnifying device used to quickly locate objects in the sky.
• Smartphone Adapter: Allows attachment of a smartphone to capture images through the eyepiece.

Figure 3.2: Included Accessories
This image displays the essential accessories provided with the telescope: the diagonal for comfortable viewing, two Plössl eyepieces (9.7mm and 26mm) for different magnifications, a 2x Barlow lens to double eyepiece power, and a red dot finder for easy object location.

4. Setup

4.1 Unpacking

Carefully remove all components from the packaging. It is recommended to keep the original packaging for future storage or transport.

4.2 Tripod Assembly

1. Spread the tripod legs outwards until they are fully extended and stable.
2. Adjust the height of the tripod legs to your desired viewing level. Secure them using the locking clamps.
3. Attach the accessory tray to the center brace of the tripod. This tray provides stability and a convenient place for your eyepieces.

4.3 Telescope Tube Attachment

1. Locate the pan-tilt alt-azimuth mount on top of the tripod.
2. Align the optical tube assembly (OTA) with the mounting bracket on the mount.
3. Secure the OTA to the mount using the provided screws or clamps, ensuring it is firmly attached but not overtightened.

Figure 4.1: Assembled Telescope with Smartphone Adapter
This image shows the complete telescope setup, including the main optical tube, alt-azimuth mount, tripod, and a smartphone securely mounted to the eyepiece for astrophotography.

4.4 Eyepiece and Diagonal Installation

1. Loosen the thumbscrew on the focuser drawtube.
2. Insert the diagonal into the focuser drawtube. Tighten the thumbscrew to secure it.
3. Loosen the thumbscrew on the diagonal.
4. Insert your desired eyepiece (e.g., 26mm for lower magnification) into the diagonal. Tighten the thumbscrew to secure it.

4.5 Red Dot Viewfinder Installation and Alignment

1. Attach the red dot viewfinder to its designated bracket on the telescope tube.
2. To align the viewfinder, point the main telescope at a distant, stationary object (e.g., a treetop or street sign) during daylight hours.
3. Look through the lowest power eyepiece and center the object in the main telescope's field of view.
4. Turn on the red dot finder. Adjust the horizontal and vertical alignment screws on the finder until the red dot is centered on the same object you see in the eyepiece.

4.6 Smartphone Adapter Attachment

1. Secure your smartphone into the adapter.
2. Carefully place the adapter over the eyepiece. Ensure the smartphone camera lens is aligned with the eyepiece.
3. Adjust the adapter to hold the phone firmly in place.

Figure 4.2: Smartphone Adapter in Use
This close-up image demonstrates the smartphone adapter attached to the telescope's eyepiece, with a smartphone displaying a magnified view of the moon, ready for astrophotography.

5. Operating the Telescope

5.1 Focusing

Once an object is centered in your eyepiece, slowly turn the focus wheel until the image appears sharp and clear. Fine adjustments may be needed as objects move or as your eyes adjust.

5.2 Locating Objects with the Red Dot Viewfinder

With the red dot viewfinder aligned (as per Section 4.5), look through the finder and move the telescope until the red dot is positioned directly on your target object. Then, look through the main telescope's eyepiece; the object should be within your field of view.

5.3 Changing Magnification

Your telescope comes with two eyepieces (9.7mm and 26mm) and a 2x Barlow lens. To change magnification:

• Lower Magnification (Wider Field of View): Use the 26mm eyepiece. This is ideal for locating objects and viewing larger celestial bodies or star fields. (Magnification: 700mm / 26mm = 26.9x)
• Higher Magnification (Narrower Field of View): Use the 9.7mm eyepiece for more detailed views of the Moon and planets. (Magnification: 700mm / 9.7mm = 72x)
• Using the Barlow Lens: Insert the Barlow lens into the diagonal first, then insert an eyepiece into the Barlow lens. This doubles the magnification of the eyepiece. For example, with the 26mm eyepiece and 2x Barlow, magnification is 53.8x. With the 9.7mm eyepiece and 2x Barlow, magnification is 144x.

5.4 Observing Celestial Objects

• The Moon: Start with the 26mm eyepiece to view the entire lunar surface, then switch to the 9.7mm or 9.7mm with Barlow for detailed views of craters and mountains.
• Planets: Planets appear as small disks. Use higher magnifications (9.7mm eyepiece or with Barlow) to observe details like Jupiter's moons or Saturn's rings.
• Deep-Sky Objects: Star clusters and nebulae are best viewed with lower magnifications (26mm eyepiece) to capture their full extent.

5.5 Terrestrial Observation

Your refractor telescope can also be used for observing distant land objects. Note that the diagonal will produce an image that is upright but laterally reversed (mirror image). For fully corrected images, a separate erecting prism (not included) would be required.

5.6 Smartphone Astrophotography

With the smartphone adapter attached (Section 4.6), open your phone's camera app. Position the phone to align the camera lens with the eyepiece. You may need to zoom in slightly on your phone to eliminate vignetting (dark edges). Use your phone's camera controls to adjust exposure and focus for the best image. This is particularly effective for capturing images of the Moon.