Calculateur d'Effet de Réducteur Focal
Calculez l'effet d'un réducteur focal sur votre télescope.
Effective Focal Length
630.00 mm
Effective Focal Length vs Native Focal Length
Formule
## Focal Reducer Effect A focal reducer shortens the effective focal length, widening the FOV and making the system faster. ### Formulas **f_eff = f * R** **N_eff = N * R** where R is the reduction factor (e.g., 0.63). The speed gain (for extended objects) scales as 1/R squared, because the same light is concentrated into a smaller image.
Exemple Résolu
1000 mm f/10 scope with a 0.63x reducer.
- 01f_eff = 1000 * 0.63 = 630 mm
- 02N_eff = 10 * 0.63 = f/6.3
- 03Speed gain = 1 / 0.63^2 = 2.52x faster
Questions Fréquentes
Does a focal reducer affect star size?
Ideally no. A good reducer maintains or improves star quality across the field. Cheap reducers may introduce coma or field curvature.
Can I use any reducer on any telescope?
No. Reducers are designed for specific back-focus distances and optical designs. Using the wrong reducer degrades image quality.
Is a reducer always beneficial?
For wide-field imaging of extended objects, yes. For planetary imaging (small targets), the native focal length or a Barlow may be better.