Takahashi introduced their Epsilon
Series flat-field hyperbolic astrographs in the middle 1980’s. The
Epsilon-130 was the smallest aperture and most portable of the series.
Now Takahashi is re-introducing the new ε-130D digital version of this
The Epsilon optical system features a
hyperbolic primary and a digital corrector to produce a flat field
image. Takahashi has been producing hyperbolic mirrors since 1985 and
has a reputation for producing high quality hyperbolic astrographs like
the current ε-180ED.
The new ε-130D is the same size as the
original ε-130 and was designed with an improvement in optical
performance with a newly designed digital corrector. This produces an
improvement in sharpness and a 1/3rd improvement in the size of the spot
equaling the ε-180 with <10µm spots at the edge of the Ø44mm circle.
The improvement in the design of the
digital corrector produces a 1/3rd reduction in the size of the smallest
stellar image. Distortion has also been reduced by ½ with the new
design of the digital corrector used on the ε-130D.
The ε-130D has a 5.9° field of view
that is perfect for imaging comets like the new comet ISON. With a speed
of f/3.3 and a 430mm focal length images will be high contrast. The
ε-130D will shorten exposures, increase color saturation and produce a
wide field high performance images.
With an f/3.3 system the speed
necessitates a large secondary that will illuminate the image properly.
Placing the diagonal mirror in the center of the tube will produce
uneven illumination across the field imaged. In order to fully
illuminate the image circle the secondary must be offset to accept the
full light cone produced by the primary mirror. The spider was
specially strengthened to hold the mirror offset securely without any
The focuser has been improved to allow
or more precise focusing. Each has a metal insert with a special
non-cold flow material to allow for the precise focus.
The ε-130D features a new collimation
system for the primary mirror, which is similar to the one used on the
TOA. The previous design used push and pull screws set inside of each
other. This modified system used separate push and pull adjusting
screws. This flush design prevents the tube from being bumped because
the protruding alignment bolts of the old design protruded past the end
of the tube.
The ε-130D is a highly portable,
airline transportable, compact hyperbolic flat field astrograph, weighs
only 10.8lbs, that can be taken easily to remote sites or around the
world. Its light weight and 5.9° apparent field of view make it perfect
for comets and wide field imaging. Its light weight allows it to be
carried by smaller and lighter high quality mounts.
|Name||Takahashi - Epsilon 130D Astrograph
|Manufacturer Part No
||44mm (5.9° field of view)
|Optical tube diameter
|Optical Tube Length