The William Optics Pleiades telescope features a highly advanced optical system consisting of seven precision lenses, combined with an extremely fast focal ratio. Due to this optical design, achieving accurate back focus is critical to optimal image quality.
The required back focus distance is exactly 55mm, measured from the rear flat surface of the telescope to your camera sensor.
Please ensure your imaging train is correctly spaced to achieve sharp, aberration-free images.
All camera adapters on the Pleiades are equipped with fine-tuning mechanisms for back focus adjustment. These have been factory-set for optimal performance, but if adjustments are needed (refer to Evaluating Back Focus Offset) there are two methods available:
- Using the included spacer rings (recommended):
Both the M48 and M54 adapters come with a set of 3 spacers (6 in total):
Thickness: 0.3mm / 0.5mm / 1.0mm
These can be stacked between the telescope and your imaging train to precisely reach 55mm.
- Using the built-in fine adjustment threads:
- Adjust the back adapter to the required distance.
- Tighten the ring against the Rotator.
We strongly recommend using spacers for minor back focus adjustments.
Rotating the threaded fine-tuning ring may introduce larger variations and should be used only if necessary.
To unleash the full potential of your professional-grade Pleiades telescope, it is essential to dial in the back focus with precision. Proper adjustment is key to achieving the telescope’s highest optical performance.