Askar 50P Telescope Instruction Manual

1. Introduction

The Askar 50P is a compact optical tube assembly (OTA) designed for deep-sky astrophotography and visual astronomy. It features a 50mm aperture, 190mm focal length, and a fast f/3.8 focal ratio. This manual provides essential information for the proper setup, operation, and maintenance of your Askar 50P Telescope.

This telescope incorporates a quadruplet Petzval APO optical design with one SD glass element, optimized for APS-C format and 1-inch sensors. Its self-flattened design eliminates the need for additional correctors, allowing direct camera attachment for flat-field imaging.

2. Product Features

• Compact and Portable Design: Combines a 50mm aperture, 190mm focal length, and f/3.8 focal ratio in a lightweight form factor.
• Quadruplet Petzval APO Optical System: Features one SD glass element and cemented rear elements, supporting APS-C format and optimized for 1-inch sensors.
• Self-Flattened Design: No additional correctors are required for flat-field imaging.
• Reversible Lens Hood: Extends to block stray light during use and reverses for compact storage, offering convenience and protection.
• Dual Finder Bases: Integrated on both sides of the tube ring for versatile accessory mounting.
• Multiple M4 Threaded Holes: Reserved for expanding with various astronomical accessories.
• 160mm Vixen-style Dovetail Plate: Provides secure mounting options.

3. Components Overview

Figure 3.1: The Askar 50P Telescope, a compact optical tube assembly.

Figure 3.2: Detailed view of the integrated single-speed focuser ring with standard MXL teeth and the front M52 filter thread.

Figure 3.3: The multi-functional handle and the rear 360° rotation scale with a locking screw for flexible framing.

Figure 3.4: Diagram illustrating the Quadruplet Petzval APO optical design, including one SD glass element.

Figure 3.5: Comparison showing the improved resolution, contrast, and color fidelity achieved with SD glass compared to standard glass.

Figure 3.6: The Askar 50P mounted as a guide scope on a main telescope, utilizing its finder scope platform.

Figure 3.7: Dimensional drawing of the Askar 50P Telescope, showing its compact size.

4. Setup

1. Mounting the Telescope:

   The Askar 50P is equipped with a 160mm Vixen-style dovetail plate for secure attachment to compatible mounts. Ensure the dovetail plate is firmly seated and locked into your mount's saddle.

   

   Figure 4.1: The 160mm Vixen-style dovetail plate for mounting the telescope.
2. Attaching Accessories:

   The telescope features dual finder bases on the tube ring, allowing for the attachment of a finder scope or guide scope. Multiple standard M4 threaded holes are also available for other astronomical accessories.

   

   Figure 4.2: Example of accessories mounted on the Askar 50P using the integrated finder bases and M4 threaded holes.

3. Camera Connection:

   The rear interface includes an M48 thread with a built-in 2-inch filter thread, suitable for connecting various cameras and imaging accessories. Due to its self-flattened optical design, no additional field flatteners are required for astrophotography with compatible sensors.

   

   Figure 4.3: Connecting a camera to the Askar 50P's M48 rear interface.

5. Operation

1. Focusing:

   The Askar 50P utilizes a helical focuser for precise adjustments. Rotate the focusing ring to achieve sharp focus for your imaging or visual observation setup. The integrated single-speed focuser ring provides smooth operation.

2. Framing and Rotation:

   The rear section of the telescope features a 360° rotation scale with a locking screw. This allows for flexible framing of your target without rotating the entire telescope or camera, which is particularly useful in astrophotography.

3. Lens Hood Management:

   Extend the lens hood during use to effectively block stray light and minimize internal reflections. For storage or transport, reverse the lens hood to reduce the overall length of the telescope and protect the objective lens.

6. Maintenance

• Cleaning Optics: Use a soft, lint-free cloth and specialized optical cleaning solution to gently clean the lens surfaces. Avoid touching the optical surfaces directly with your fingers.
• Dust Protection: Always keep the dust caps on the front and rear of the telescope when not in use to prevent dust accumulation.
• Storage: Store the telescope in a dry, cool environment, away from direct sunlight and extreme temperature fluctuations.
• Mechanical Parts: Periodically check all screws and connections to ensure they are secure. Avoid over-tightening.

7. Troubleshooting

• Unsharp Images: Ensure proper focus using the helical focuser. Check for atmospheric conditions (seeing) that might affect image clarity. Verify correct back focus distance for your camera setup.
• Vignetting: Confirm that your camera sensor size is compatible with the telescope's optimized field (APS-C/1-inch sensors). Check for any adapters or filters that might be causing obstruction.
• Chromatic Aberration: While the SD glass minimizes chromatic aberration, extreme conditions or improper focusing can sometimes reveal minor color fringing. Re-check focus and ensure all optical elements are clean.
• Mounting Instability: Ensure the dovetail plate is securely attached to the mount and all locking mechanisms are tightened. Balance your setup properly to prevent vibrations.

8. Specifications

9. Warranty and Support

The Askar 50P Telescope comes with a 1-year warranty from the date of purchase. This warranty covers manufacturing defects and material flaws under normal use.

For technical support, warranty claims, or service inquiries, please contact the seller, SHARPSTAR OPTICS, directly through your purchase platform or their official contact channels. Please retain your proof of purchase for warranty validation.

For additional resources and product information, you may visit the Askar Store on Amazon.