Optics / Telescope Accessories
User Manual for Askar 107PHQ Astro Camera Lens
Comprehensive user guide for the Askar 107PHQ astrograph. Includes setup instructions, connection diagrams, technical specifications, and component details for imaging and visual observation.
Table of contents
Manual images
Click an image to enlargeQuick guide from the manual
The Askar 107PHQ is a long-focal-ratio flatfield astrograph designed for both astrophotography and visual observation. A key advantage of this model is the built-in flatfield lens, which eliminates the need for an external field flattener, simplifying back-focus calculations and connection steps. The system supports full-frame imaging with a 44mm image circle.
Product Description
The 107PHQ features a quadruplet air-spaced APO design, including two ED glass elements to reduce chromatic aberration. It is constructed with high-quality CNC-machined components and includes a 3.4-inch rigid focuser capable of handling a load of 8kg, with a 95mm travel distance suitable for visual observation.
Package Contents
- 107PHQ OTA (Optical Tube Assembly)
- Pair of tube rings
- Handle
- Askar 300mm Vixen dovetail plate
- Set of four-piece photographic adapters
- High-quality aluminum suitcase
- User manual
Product Parts
The main components include the lens hood with a locking screw handle, the main tube, a multi-functional tube ring, and a dovetail plate. The focuser assembly features a finder base, rotator locking screw, coarse and fine adjustment knobs, and a bottom locking screw. Adapters are provided for 2-inch to 1.25-inch conversion and M86 to 2-inch conversion.
Imaging and Connection
To connect imaging devices, use the provided four-piece adapter set. The back-focus distance (from the base of the thread) varies depending on the adapter used:
- M48x0.75 thread: 79mm
- M54x0.75 thread: 99mm
- M68x1 thread: 119mm
- M86x1 thread: 149mm
For visual observation, the back-focus distance is 120mm from the end of the 2-inch visual back.
Technical Specifications
- Aperture size: 107mm
- Focal length: 749mm
- Focal ratio: f/7
- Objective lens: Quadruplet air-spaced APO (including two ED glass)
- Image circle: 44mm
- Net weight: 5.7kg
- Gross weight: 6.9kg
- Total length: 603mm (dew shield contracted) to 806mm (dew shield extended with adapters)
Safety Warnings
WARNING: Do not look at the sun through the telescope. Doing so will cause irreversible damage to your eyes.
Practical help
Common problems
Difficulty achieving focus with imaging equipment
Ensure your imaging train is within the specified back-focus distance (79mm to 149mm depending on the adapter used) and that the focuser is within its 95mm travel range.
Adapter connection issues
Verify you are using the correct adapter from the four-piece set (M86, M68, M54, M52, M48) to match your camera's thread requirements.
Before use
- Check if the dew shield is extended or contracted based on your current setup requirements.
- Verify that the tube rings and dovetail plate are securely fastened to your mount.
- Ensure the focuser bottom locking screw is adjusted correctly before mounting heavy cameras.
- Confirm the imaging device is compatible with the required back-focus distance for the chosen adapter.
- Inspect the lens hood locking screw to ensure it is tight during transport or storage.
Specs in practice
- Aperture (107mm)
- The diameter of the objective lens, determining the light-gathering power of the telescope.
- Focal Length (749mm)
- The distance between the lens and the focal point, determining the magnification and field of view.
- Focal Ratio (f/7)
- The ratio of the focal length to the aperture, indicating the speed of the optical system for photography.
- Image Circle (44mm)
- The diameter of the area where the image is sharp, confirming compatibility with full-frame sensors.
Images and diagrams
- Product Size Diagram: Shows the physical dimensions of the OTA with the dew shield contracted and extended.
- Connection Diagram: Illustrates the assembly sequence from the focuser to the camera using the four-piece adapter set.
- Locking Screw Position Diagram: Identifies the bottom locking screw and adjustment holes for installing electric focusing brackets.
- Four-piece Adapters Diagram: Details the thread sizes (M86, M68, M54, M52, M48) for the adapter set.
Model compatibility
- Supports full-frame imaging sensors (44mm image circle).
- Compatible with 1.25-inch and 2-inch diagonals for visual observation.
- Focuser is compatible with electric focusing bracket installation using the designated screw holes.
Manual page author
Emily Carter
User documentation editor
Prepares concise manual descriptions and highlights the most useful setup, operation, and maintenance information for readers.