My Epsilon 160D, hosted at Starfront Observatory.
The Takahashi Epsilon 160D is a high-performance astrograph designed specifically for deep-sky imaging with modern digital CMOS cameras. Building upon the legacy of its predecessors, the 160D brings an improved optical system that prioritizes a flat field, sharp stars across large sensors, and a fast focal ratio that enables shorter exposure times. For astrophotographers seeking a compact yet powerful wide-field imaging platform, the Epsilon 160D offers a compelling package.
IC 348 shot from Starfront Observatory.
Optical Design: What Makes the Epsilon 160D Exceptional?
The Epsilon 160D employs a modified hyperbolic optical design that sets it apart from traditional Newtonian and Ritchey-Chrétien telescopes. Takahashi has engineered this system to optimize imaging performance, particularly for modern CMOS cameras that demand high resolution and minimal aberrations across a full-frame sensor. Here are the key elements that make this design unique:
1. Hyperbolic Primary Mirror with ED Corrector Lens
Unlike standard parabolic reflectors, which require a coma corrector for astrophotography, the hyperbolic mirror in the Epsilon 160D naturally mitigates coma while maintaining a fast f/3.3 focal ratio. This design results in highly corrected, pinpoint stars even at the field edges.
To further enhance the optical performance, Takahashi incorporates a two-element corrector lens, one of which is made from ED (Extra-low Dispersion) glass. This corrector flattens the field, reduces chromatic aberration, and sharpens the star images across the entire imaging plane, making the telescope highly suitable for large-format sensors.
2. Large, Well-Corrected Imaging Circle
A critical feature for astrophotographers using full-frame CMOS cameras is the size and correction of the imaging circle. The Epsilon 160D boasts a fully corrected 44mm image circle, making it ideal for modern sensors like the Sony IMX455 (found in the QHY600 and ZWO ASI6200). Unlike traditional Newtonians, which exhibit significant off-axis coma and require extensive additional correction, the Epsilon 160D produces sharp stars right to the edge with minimal vignetting.
3. Advanced Light Suppression and Baffling
To minimize stray light and improve contrast, Takahashi has refined the light path with internal baffling and an eccentric oblique mirror placement. This reduces internal reflections and suppresses diffraction spikes, ensuring that faint nebulae and galaxy structures remain high in contrast and free from optical artifacts.
Set up and testing before sending to its remote home for imaging.
Hands-On Experience
Setup and Build Quality
Takahashi telescopes are known for their excellent mechanical construction, and the Epsilon 160D is no exception. The optical tube assembly (OTA) is compact and well-balanced, weighing 6.9 kg (15.2 lbs), making it manageable for most equatorial mounts in the mid-range payload class (e.g., Sky-Watcher EQ6-R, Pegasus Astro NYX-101).
The included low-profile Crayford focuser with a rotary connector system allows for smooth and precise focusing. Unlike rack-and-pinion focusers, which can suffer from backlash, the Crayford system ensures fine control—critical for achieving precise focus at f/3.3. Some users, however, prefer to upgrade to an electronic focuser like the Pegasus Astro FocusCube for automated focusing during long imaging sessions.
Additionally, due to the camera placement near the front light opening, it is highly recommended to use a light shroud or dew shield to prevent unwanted light intrusion and reduce the risk of condensation. This simple addition helps maintain contrast and image quality, particularly in humid or light-polluted environments.
Collimation and Maintenance
Collimation is a vital factor in fast astrographs, and the Epsilon 160D requires careful adjustment for optimal performance. Fortunately, Takahashi has improved the collimation system, incorporating push-pull primary mirror adjustments similar to those found in the Epsilon 180ED. A removable central cover allows for quick cooling and access to the mirror, reducing thermal acclimation time.
Initial collimation may require careful tweaking, the system holds alignment well once dialed in. The Takahashi Collimating Eye Piece is highly recommended, as it is specially designed to reflect the crosshairs in the secondary, ensuring perfect collimation. Unlike laser collimators or the standard Takahashi Collimating Scope, this tool provides superior accuracy for this optical design.
Focusing Performance
Many users have reported issues with the stock focuser, citing minor flexure and difficulty maintaining critical focus at f/3.3. However, by connecting a ZWO EAF (Electronic Automatic Focuser), I have personally achieved perfect focus runs night after night. The precise and repeatable autofocus capabilities of the ZWO EAF significantly enhance usability, particularly for unattended imaging sessions or temperature-variable environments.
Performance Analysis: Imaging Results
The Angel Nebula, shot at Starfront Remote Observatory.
Real-world imaging tests confirm that the Epsilon 160D delivers outstanding astrophotography results. Star sizes across the frame are within 3 microns, which is an incredible level of correction for a telescope in this class. This precision ensures that even in broadband RGB and narrowband imaging, stars remain tight and free from aberrations.
The fast f/3.3 focal ratio allows astrophotographers to capture deep-sky objects with shorter exposure times, reducing the total integration time required compared to f/4 or f/5 systems. This means an exposure that takes 10 minutes at f/5 would take about 4 minutes and 20 seconds at f/3.3 to reach the same depth. Making the scope particularly effective for narrowband imaging, where shorter exposures help combat the effects of skyglow and thermal noise.
A two-panel mosaic (my first) shot from Starfront Observatory.
Recommended Accessories
To maximize performance, consider the following accessories:
Astronomik MaxFR HA, SII, and OIII Narrowband Filters – Optimized for high-speed imaging at f/3.3.
Astronomik Deep Sky RGB Set – Ideal for capturing vibrant broadband images.
Electronic Focuser (Pegasus FocusCube or ZWO EAF) – Helps maintain critical focus.
Takahashi Collimating Eye Piece – Ensures precise collimation.
Dew Heater System – The corrector lens is prone to dewing in humid conditions.
Light Shroud/Dew Shield – Prevents unwanted light intrusion and reduces condensation risk.
Summary & Final Thoughts
The Takahashi Epsilon 160D is a top-tier wide-field astrograph that excels in modern astrophotography. Its combination of a hyperbolic mirror, ED corrector lens, and large, well-corrected imaging circle makes it one of the best choices for CMOS-based astrophotographers looking for ultra-sharp stars and a fast, efficient imaging system. While it requires meticulous collimation and precise focusing, its performance outshines many competitors in its class.
For those seeking a premium fast astrograph, the Epsilon 160D is an investment worth considering. If you’re interested in purchasing, be sure to visit Agena Astro to support Mac Observatory’s continued high-quality reviews and articles.