The Takahashi TOA-645 Flattener for TOA-130NS is a 0.99x field flattener for the TOA-130NS Ortho-Apo triplet refractor. The TOA-645 Flattener has a large image circle of 60mm, making it suitable for use with medium format sensors. When paired with the TOA-130, the focal length is slightly reduced to 990mm and focal ratio to f/7.6.
The TOA-645 Flattener is an evolution of the TOA-67FL super-reducer, optimized for modern large CMOS sensors with small pixels. While the TOA range of refractors give perfect correction of chromatic and spherical aberration, this focus on the best possible aberration correction results in greater field curvature. As a result, the image is distorted at the edges of the field unless a flattener or reducer is used.
The TOA-645 Flattener transcends the limitations of the earlier TOA-67FL and TOA-35FL correctors, providing an optimal solution for both the TOA-130 and TOA-150 to be used to their full potential.
The TOA-645 Flattener for TOA-130NS TKA31587S includes the M72 Extension Tube (L) set, providing the necessary spacing for DSLRs and allowing an M54 x 0.75 connection to common imaging systems.
Spot diagram of Takahashi TOA-130 with TOA-645 field flattener.
|83.7 mm (from M72 x 1 thread), 56.2 mm (from CA35 ring with M54 x 0.75)
|Connection telescope side
|M72 x 1 male
|Connection camera side
|M72 x 1 female, M54 x 0.75 female