The RiDK (Riccardi Dall-Kirkham) represents the new reference point for all modified Dall-Kirkham instruments available on the market.
- ENTRY PUPIL DIAMETER:
- 500 mm (20'')
- FOCAL RATIO:
- FOCAL LENGTH:
- 3500 mm (140'')
- LINEAR OBSTRUCTION:
- FULLY CORRECTED AND ILLUMINATED FIELD:
- 80 mm
- 85 Kg
- BACK FOCUS EXTRACTION (FROM BACK PLATE):
- about 240 mm (9.5'')
The results are simply amazing: a telescope that offers a wide, flat focal plane (more than 65 mm in diameter, even in the smallest model!). A wide focal plane that is diffraction limited over a wide spectral range.
Since the corrector group is close to the focal plane, chromatic aberration is undetectable.