Introduction
The CELESTRON Libra 70500 Astronomy Telescope is a compact and portable refracting telescope designed for beginners and students interested in astronomical observation. Featuring a 70mm objective lens and a 500mm focal length, it provides clear views of celestial objects. The telescope comes with a sturdy stainless steel tripod and various accessories to enhance your viewing experience.
Figure 1: Fully assembled CELESTRON Libra 70500 Telescope.
Package Contents
Before assembly, please ensure all parts are present and in good condition:
- Telescope Optical Tube Assembly (OTA)
- AZ Theodolite Mount
- Stainless Steel Tripod
- MA Eyepiece 20mm (25X)
- Aspheric Eyepiece 4mm (125X)
- 2X Barlow Lens
- 90-degree Zenith Mirror
- 6x24 Optical Finder Scope
- Accessory Tray
- Carrying Bag
- Smartphone Adapter (optional, if included)
Figure 2: Included accessory tray and portable carrying bag.
Setup Instructions
Follow these steps to assemble your telescope:
- Set up the Tripod:
Extend the legs of the stainless steel tripod to a stable height. Secure the legs using the locking mechanisms. Attach the accessory tray to the center brace of the tripod for stability and convenience.
Figure 3: Tripod with accessory tray attached.
- Attach the AZ Theodolite Mount:
Mount the AZ theodolite bracket onto the top of the tripod. Ensure it is securely fastened. This mount allows for easy horizontal and vertical movement of the telescope.
- Install the Optical Tube Assembly (OTA):
Carefully attach the telescope's optical tube to the AZ mount. Use the provided screws or clamps to secure it firmly. Ensure the objective lens (larger end) is facing forward.
Figure 4: Exploded view of telescope components and assembly.
- Attach the Finder Scope:
Locate the 6x24 optical finder scope and attach it to its designated bracket on the main telescope tube. The finder scope helps in locating objects before viewing them through the main eyepiece.
- Insert the Zenith Mirror and Eyepiece:
Insert the 90-degree zenith mirror into the focuser of the telescope. Then, insert your chosen eyepiece (e.g., 20mm MA eyepiece for lower magnification) into the zenith mirror. Secure with the thumbscrew.
Figure 5: Included eyepieces and Barlow lens for varying magnifications.
Video 1: Product demonstration showing assembly and usage in various outdoor settings.
Operating Instructions
- Aligning the Finder Scope:
Before observing, align the finder scope with the main telescope. Point the main telescope at a distant, easily identifiable object (e.g., a tree top or a street light during the day). Look through the finder scope and adjust its alignment screws until the object is centered in its crosshairs. Then, check through the main eyepiece to ensure the object is also centered there.
Figure 6: Using the finder scope to pinpoint objects.
- Observing an Object:
Once the finder scope is aligned, use it to locate your desired celestial object. Center the object in the finder scope's crosshairs. Then, look through the main telescope's eyepiece. You may need to make minor adjustments to the telescope's position using the AZ mount's handles.
- Focusing:
Turn the focuser knob (located near the eyepiece) slowly until the image appears sharp and clear. The focuser has a scale for precise adjustment.
Figure 7: Detail of the focuser with its adjustment scale.
- Changing Magnification:
To change magnification, swap eyepieces. The 20mm MA eyepiece provides 25X magnification (500mm focal length / 20mm eyepiece focal length). The 4mm aspheric eyepiece provides 125X magnification (500mm / 4mm). For even higher magnification, insert the 2X Barlow lens into the focuser first, then insert an eyepiece into the Barlow lens. This doubles the magnification of any eyepiece used with it.
- Using the Smartphone Adapter:
If included, attach the smartphone adapter to an eyepiece. Secure your smartphone to the adapter and align its camera with the eyepiece to capture images or videos through the telescope.
Figure 8: Smartphone adapter in use for astrophotography.
Maintenance
- Cleaning Lenses: Use a soft, lint-free cloth specifically designed for optical lenses. For stubborn smudges, use a small amount of optical cleaning fluid. Avoid touching the lens surfaces with your fingers.
- Storage: When not in use, store the telescope in its carrying bag in a dry, dust-free environment. Keep dust caps on the objective lens and eyepieces.
- General Care: Avoid exposing the telescope to extreme temperatures or humidity. Do not disassemble the optical components unless instructed by a qualified technician.
Troubleshooting
- Image is blurry: Adjust the focuser knob slowly until the image is sharp. Ensure the eyepiece is fully inserted and secured.
- Cannot find objects: Ensure the finder scope is properly aligned with the main telescope. Start with the lowest magnification eyepiece (20mm MA) to get a wider field of view.
- Image is dim: This is normal for very high magnifications or when observing faint objects. Ensure your objective lens is clean. Observe from a dark location away from light pollution.
- Telescope is unstable: Ensure the tripod legs are fully extended and locked, and the accessory tray is attached for added stability. Place the tripod on a flat, firm surface.
Specifications
| Feature | Specification |
|---|---|
| Product Model | Libra 705 |
| Objective Lens Diameter | 70mm |
| Focal Length of Objective Lens | 500mm |
| Eyepiece 1 | MA Eyepiece 20mm (25X) |
| Eyepiece 2 | Aspheric Eyepiece 4mm (125X) |
| Zenith Mirror | 90-degree Positive Mirror |
| Tube Material | Aluminum Alloy |
| Optical Structure | Refractive |
| Star Finder | 6x24 Optical Star Finder |
| Magnifier | 2X Barlow Lens |
| Bracket | AZ Theodolite |
| Coating | Multilayer Coating (FMC) |
| Tripod | Stainless Steel Tripod |
| Magnification (Max) | 125x (with 4mm eyepiece), up to 250x (with 4mm eyepiece and 2x Barlow) |
| Water Resistance Level | IPX4 |
| Material | Metal |
User Tips
- Start with Low Magnification: Always begin observing with the lowest magnification eyepiece (20mm MA) to easily locate and center objects. Once centered, you can switch to higher magnification eyepieces.
- Observe from Dark Locations: For the best astronomical views, find a location away from city lights and light pollution.
- Allow for Temperature Acclimation: If moving your telescope from a warm indoor environment to a cold outdoor one, allow it some time (15-30 minutes) to accustom to the ambient temperature. This helps prevent image distortion due to temperature differences.
- Practice Terrestrial Viewing: Before attempting complex astronomical observations, practice using your telescope for terrestrial viewing during the day. This helps you get familiar with focusing and tracking.
Warranty and Support
For warranty information, technical support, or service inquiries, please refer to the documentation provided with your purchase or contact the seller directly. Keep your proof of purchase for any warranty claims.
