Celestron Omni 2x Barlow Lens Instruction Manual

1. Introduction to Your Celestron Omni 2x Barlow Lens

The Celestron Omni 2x Barlow Lens is an essential accessory designed to enhance the magnification capabilities of your telescope. By inserting this lens between your eyepiece and your telescope, you can effectively double the magnification of any eyepiece you own, providing a wider range of viewing options without needing to purchase additional eyepieces.

This Barlow lens features two-element, fully multi-coated optics with blackened edges, which work to maximize light transmission and minimize internal reflections, ensuring clear and sharp images. Its 1.25-inch barrel is compatible with standard 1.25-inch focusers and diagonals, and it securely accepts 1.25-inch eyepieces with a metal thumbscrew.

Image 1: The Celestron Omni 2x Barlow Lens.

2. Key Features and Benefits

• Doubles Magnification: Instantly doubles the magnification of any 1.25-inch eyepiece, effectively expanding your eyepiece collection.
• Maintains Eye Relief: Unlike shorter focal length eyepieces that reduce eye relief, the Barlow lens doubles magnification while preserving the comfortable eye relief of your original eyepiece. This is particularly beneficial for eyeglass wearers.
• High-Quality Optics: Equipped with fully multi-coated, two-element optics and blackened lens edges to ensure excellent light transmission and contrast, reducing glare and internal reflections.
• Standard Compatibility: Designed with a 1.25-inch barrel to fit seamlessly into most standard telescope focusers and diagonals, and accepts all 1.25-inch eyepieces.
• Durable Construction: Features a machined high-grade aluminum barrel for robust and long-lasting performance.

Image 2: Detailed view of the Celestron Omni 2x Barlow Lens highlighting its features, including the 1.25" eyepiece acceptance, 2x magnification capability, fully multi-coated 2-element optics, and 1.25" internally threaded barrel.

Image 3: The Barlow lens in a telescope, illustrating the benefit of fully multi-coated 2-element optics for sharp, distortion-free images against a starry background.

3. Setup and Installation

Installing your Celestron Omni 2x Barlow Lens is a straightforward process. Follow these steps to integrate it with your telescope and eyepiece:

1. Prepare Your Telescope: Ensure your telescope is set up and ready for observation.
2. Remove Eyepiece: Carefully remove the eyepiece from your telescope's focuser or diagonal.
3. Insert Barlow Lens: Insert the chrome barrel of the Celestron Omni 2x Barlow Lens into the focuser or diagonal. Secure it in place using the thumbscrew on the focuser/diagonal.
4. Insert Eyepiece: Insert your desired 1.25-inch eyepiece into the top opening of the Barlow lens. Secure the eyepiece with the Barlow lens's metal thumbscrew.
5. Adjust Focus: Look through the eyepiece and adjust your telescope's focuser until the image is sharp.

The Barlow lens effectively doubles the magnification of the eyepiece it is paired with. For example, a 25mm eyepiece will provide the magnification equivalent to a 12.5mm eyepiece when used with the 2x Barlow, and a 10mm eyepiece will perform like a 5mm eyepiece.

Image 4: A hand demonstrating the insertion of the Celestron Omni 2x Barlow Lens into a telescope's diagonal, showing its standard 1.25" format compatibility.

4. Operating Your Barlow Lens

The primary function of the Barlow lens is to increase the effective focal length of your telescope, thereby increasing the magnification of any eyepiece used with it. This allows for more detailed observations of celestial objects.

Magnification Principle:

When using the 2x Barlow lens, the magnification of your eyepiece is doubled. This means a 25mm eyepiece will yield the magnification of a 12.5mm eyepiece, and a 10mm eyepiece will yield the magnification of a 5mm eyepiece. This effectively expands your range of available magnifications.

Image 5: Visual comparison of the Moon's appearance without a Barlow lens versus with a Barlow lens, demonstrating the increased magnification. An illustration also shows the magnification formula: (Focal Length of Telescope / Focal Length of Eyepiece) x Barlow Factor = Magnification.

Eye Relief Benefit:

A significant advantage of using a Barlow lens is that it helps maintain comfortable eye relief. Shorter focal length eyepieces, which provide higher magnification, typically have very short eye relief, requiring your eye to be very close to the lens. By using a longer focal length eyepiece with a Barlow, you achieve high magnification while retaining the longer, more comfortable eye relief of the original eyepiece. This is particularly beneficial for observers who wear eyeglasses or for extended viewing sessions.

Astronomy Tip for Refractors, Schmidt-Cassegrains, and Maksutov-Cassegrains:

When using a 2x Barlow lens with a refractor, Schmidt-Cassegrain, or Maksutov-Cassegrain telescope, the placement of the Barlow lens can affect the resulting magnification:

• If the Barlow lens is placed between the eyepiece and the diagonal, it will provide the stated 2x magnification.
• If the Barlow lens is placed between the diagonal and the telescope, it may provide a higher magnification, potentially up to 3x, depending on the specific optical path. Experimentation is encouraged to find the optimal setup for your viewing needs.

Important Note: Higher magnification does not always equate to a better view. Excessive magnification can magnify atmospheric turbulence, making images appear blurry or fuzzy. Always choose a magnification appropriate for the object being viewed and the current atmospheric conditions.

Official Product Video:

5. Maintenance and Care

Proper care and maintenance will ensure the longevity and optimal performance of your Celestron Omni 2x Barlow Lens.

• Cleaning the Optics:
  • Use a soft, lint-free cloth or a specialized optical cleaning brush to gently remove dust and loose particles.
  • For smudges or fingerprints, apply a small amount of optical cleaning fluid to a clean optical cloth (never directly to the lens) and gently wipe the surface in a circular motion.
  • Avoid touching the optical surfaces with your fingers.
• Storage:
  • Always replace the protective caps on both ends of the Barlow lens when not in use.
  • Store the lens in a clean, dry environment, preferably in its original packaging or a padded case, to protect it from dust and impact.
• Handling:
  • Handle the Barlow lens by its barrel, avoiding contact with the optical elements.
  • Ensure the thumbscrew is tightened just enough to secure the eyepiece; over-tightening can cause damage.

Image 6: A close-up view of the 1.25" machined high-grade aluminum barrel, emphasizing the robust construction of the Barlow lens.

6. Troubleshooting

If you encounter issues while using your Celestron Omni 2x Barlow Lens, consider the following common solutions:

• Image Appears Dim:
  • While modern Barlow lenses are designed for excellent light transmission, any additional optical element will slightly dim the image. This is usually minimal (around 3%).
  • Ensure your telescope's aperture is sufficient for the desired magnification. Very high magnifications on smaller telescopes can result in dim images.
  • Check for light pollution in your viewing area.
• Image is Blurry or Fuzzy:
  • Focus: Re-adjust your telescope's focuser carefully. Fine-tuning is often required with higher magnifications.
  • Atmospheric Conditions: High magnification will also magnify atmospheric turbulence (seeing conditions). On nights with poor seeing, lower magnification may provide a clearer view.
  • Collimation: Ensure your telescope's optics are properly collimated, especially for reflector telescopes.
  • Eyepiece Cleanliness: Check if the eyepiece or Barlow lens optics are dirty and clean them as per maintenance instructions.
• Eyepiece Not Fitting Securely:
  • Ensure you are using a 1.25-inch eyepiece. The Celestron Omni 2x Barlow Lens is designed for this standard size.
  • Tighten the metal thumbscrew on the Barlow lens to secure the eyepiece. Do not overtighten.

7. Specifications

8. Warranty and Support

Your Celestron Omni 2x Barlow Lens is backed by Celestron's commitment to quality and customer satisfaction.

• Warranty: This product includes a 2-Year US Warranty. Please retain your proof of purchase for warranty claims.
• Customer Support: For any questions, technical assistance, or warranty service, please contact Celestron's team of US-based experts. Unlimited support is available to assist you with your product.