Celestron AstroMaster 90 EQ Refractor Telescope

Introduction

Welcome to the world of amateur astronomy with your new Celestron AstroMaster 90 EQ Refractor Telescope. This manual provides essential information for assembling, operating, and maintaining your telescope to ensure optimal viewing experiences. Please read these instructions carefully before use.

Safety Information

WARNING: NEVER LOOK DIRECTLY AT THE SUN THROUGH YOUR TELESCOPE OR ITS FINDERSCOPE WITHOUT A PROPERLY DESIGNED SOLAR FILTER. PERMANENT AND IRREVERSIBLE EYE DAMAGE MAY RESULT.

Always ensure the telescope is securely mounted to prevent accidental falls. Keep all small parts away from children to avoid choking hazards. Handle optical components with care to prevent scratches or damage.

Parts List

Before beginning assembly, verify that all parts are present:

• Optical Tube Assembly (OTA)
• Equatorial Mount
• Adjustable Tripod with Accessory Tray
• Counterweight and Counterweight Shaft
• Finderscope with Bracket
• Eyepieces (e.g., 20mm, 10mm)
• Diagonal
• Slow-Motion Control Cables
• Basic Smartphone Adapter

Setup

Follow these steps to assemble your telescope:

1. Set up the Tripod: Spread the tripod legs apart until they are fully extended. Secure the accessory tray to the center brace of the tripod. Adjust the leg height for stability on uneven surfaces.
2. Attach the Equatorial Mount: Place the equatorial mount onto the tripod head. Secure it using the large knob or bolt located underneath the tripod head.
3. Install the Counterweight Shaft and Counterweight: Thread the counterweight shaft into the equatorial mount. Slide the counterweight onto the shaft and secure it with the locking screw.
4. Attach the Optical Tube: Locate the mounting plate on the optical tube. Align it with the dovetail saddle on the equatorial mount. Slide the optical tube into the saddle and tighten the locking screws to secure it.
5. Install the Finderscope: Slide the finderscope bracket into the dovetail slot on the optical tube. Tighten the small screw on the bracket to hold it in place. Remove the lens caps from the finderscope.
6. Insert the Diagonal and Eyepiece: Loosen the thumbscrews on the focuser. Insert the diagonal into the focuser and tighten the thumbscrews. Then, insert your desired eyepiece (e.g., 20mm for lower magnification) into the diagonal and tighten its thumbscrews.
7. Attach Slow-Motion Control Cables: Connect the slow-motion control cables to the appropriate shafts on the equatorial mount for fine adjustments in Right Ascension and Declination.
8. Attach the Smartphone Adapter: The smartphone adapter connects to an eyepiece. Place your smartphone into the adapter's clamp and secure it. Then, attach the adapter to the eyepiece, ensuring the phone's camera lens is centered over the eyepiece.

This image displays the Celestron AstroMaster 90 EQ Refractor Telescope fully assembled on its equatorial mount tripod, alongside two eyepieces and a separate smartphone adapter.

Operating the Telescope

Once assembled, you can begin observing:

1. Align the Finderscope: During daylight, point the main telescope at a distant, easily identifiable object (e.g., a telephone pole). Center the object in the main telescope's eyepiece. Then, adjust the finderscope's alignment screws until the same object is centered in the finderscope's crosshairs.
2. Focusing: Look through the eyepiece and slowly turn the focuser knob until the image is sharp.
3. Using the Equatorial Mount: The equatorial mount allows you to track celestial objects as they move across the sky. After aligning the mount to the celestial pole (a more advanced step, refer to detailed astronomy guides), you can use the slow-motion controls to follow objects with a single adjustment.
4. Using the Smartphone Adapter: With the smartphone adapter attached and your phone's camera centered over the eyepiece, open your camera app. Adjust the focus of the telescope and zoom on your phone if necessary to capture images or videos through the eyepiece.

Maintenance

Proper care ensures the longevity and performance of your telescope:

• Cleaning Optics: Use a soft, clean brush to remove dust from lenses. For smudges, use a specialized optical cleaning solution and a microfiber cloth. Avoid touching optical surfaces with bare hands.
• Storage: Store the telescope in a dry, dust-free environment. Replace all lens caps when not in use.
• General Care: Avoid exposing the telescope to extreme temperatures or sudden temperature changes. Periodically check all screws and bolts for tightness.

Troubleshooting

Here are solutions to common issues:

• Image is blurry: Adjust the focuser knob slowly. Ensure the eyepiece is fully inserted and secured. Check for condensation on the lenses.
• Cannot find objects: Verify the finderscope is properly aligned with the main telescope. Start with a low-power eyepiece (higher focal length, e.g., 20mm) for a wider field of view.
• Image is upside down or reversed: This is normal for astronomical telescopes without a correcting prism. For terrestrial viewing, a diagonal with an erecting prism is required.
• Smartphone adapter not working: Ensure the phone's camera is perfectly centered over the eyepiece. Adjust the telescope's focus and the phone's zoom.

Specifications

Warranty and Support

For detailed warranty information, please refer to the documentation included with your product or visit the official Celestron website. For technical support or further assistance, contact Celestron customer service.

You can find more information and support resources on the Celestron Store on Amazon.