Takahashi Epsilon-130D (OTA only)

The Takahashi Epsilon-130D is a specialist wide-field astrograph built around a 130mm hyperbolic primary mirror. Unlike a conventional Newtonian reflector, the Epsilon combines its hyperbolic primary and flat secondary mirror with a dedicated two-element corrector integrated into the focuser. This optical system is designed to produce a flat imaging field across a 44mm image circle, with Takahashi specifying star images of less than 10 microns at the edge of the field.

With a 430mm focal length and f/3.3 focal ratio, the Epsilon-130D is exceptionally fast for a telescope of its aperture. The resulting 5.9° field of view is particularly useful for large emission and reflection nebulae, open star fields, Milky Way regions and comets. Takahashi also describes the Epsilon as an excellent wide-field visual telescope, with star clusters, galaxies and deep-sky objects benefiting from its wide field and fine star images.

The optical design is strongly optimised for astrophotography. The secondary mirror is mounted on a reinforced spider intended to minimise flexure, while the rack-and-pinion focuser incorporates a CAA, or Camera Angle Adjuster, for photographic framing. This allows the camera orientation to be adjusted independently for composition without having to reposition the telescope itself.

The Epsilon-130D also has a particularly practical collimation system. Optical-axis markings on both mirrors allow alignment to be performed during daylight rather than requiring a star test, and Takahashi provides a dedicated collimation eyepiece system for this purpose. This makes an important maintenance task more straightforward than it can be with a conventional fast Newtonian.

The optical tube is only 460mm long and weighs approximately 4.9kg, making the Epsilon-130D relatively compact for a 130mm imaging telescope. The OTA-only version does not include the optional 6×30 finder or its bracket, and the 166WS tube rings are separate accessories.

For users who want more focal length while retaining the Epsilon’s corrected imaging performance, Takahashi offers a dedicated 1.5× Epsilon extender. On the Epsilon-130D this changes the focal length to 650mm and the focal ratio to f/5.0 while retaining a 44mm image circle. The extender is an optional accessory and is not part of the OTA package.