Bresser 102/600 Messier Hexafoc 102s OTA - Refractor Telescope
The Bresser Messier Hexafoc 102s OTA is a versatile achromat designed for more serious amateur astronomers who are looking for a quality optical tube without a mount and want to attach it to their own - paralactic or alt-azimuth - mount. The 102 mm objective diameter and 600 mm focal length (focal ratio f/5.9) offer a pleasant balance between a wide field of view and sufficient magnification for observing planets, the Moon, and deep-sky objects. What makes this model stand out is the premium 2.5" Hex focuser and a solar filter included as standard - features that are far from common at this price point.
Optics and Focal Ratio
The 102 mm objective gathers enough light to observe planets, star clusters, nebulae, and fainter stars down to approximately magnitude 13. The 600 mm focal length at f/5.9 is a well-chosen compromise that suits both beginners looking for sweeping views of constellations and more experienced observers focused on planets and double stars. Compared to shorter f/5 refractors, this telescope delivers slightly higher contrast in planetary observation while still maintaining a short enough focal length for comfortable wide-field sky tours.
The achromatic lens design corrects chromatic aberration to keep the image sharp and contrasty. For even more precise color correction, an ED filter or field flattener suitable for refractors of this aperture can be added at any time.
Hexafoc - a Focuser Above the Standard
The key feature of this model is the 2.5" rack-and-pinion Hex focuser - a focuser with a hexagonal body that eliminates the typical rotation or wobble of the eyepiece tube during focusing. This design ensures significantly more precise and stable focusing than a standard round focuser, which you will appreciate especially during astrophotography or when working with heavier eyepieces and cameras. The focuser accepts eyepieces and accessories of both 2" and 1.25" diameter via the included reduction adapter.
Also included is a 2"/1.25" adapter with an integrated T2 thread, allowing direct attachment of a DSLR or mirrorless camera without any additional adapters - simply add the correct T-ring for your camera body and you are ready to shoot.
Accessories and Equipment
The Bresser Messier 102s OTA comes with a comprehensive set of accessories that allows you to start observing right out of the box:
- Plössl 26 mm eyepiece - a quality four-element eyepiece for wide-field observation with a comfortable eye relief
- 6x30 optical finderscope - a reliable aid for sky orientation and object finding
- 1.25" diagonal mirror - for comfortable visual observation without straining your neck
- Solar filter - enables safe observation of the Sun, sunspots, and the solar limb
- Cradle rings with handle and piggyback camera holder (1/4" thread) - practical for piggyback photography directly from the telescope
- Universal 44 mm dovetail plate (Vixen standard) with stainless steel rail - compatible with the vast majority of paralactic and alt-azimuth mounts on the market
- Handle with integrated camera thread - makes carrying the tube easier and allows direct camera attachment
Technical Specifications
- Objective diameter: 102 mm
- Focal length: 600 mm
- Focal ratio: f/5.9
- Optical design: achromat refractor
- Focuser: 2.5" Hex R&P (rack-and-pinion, hexagonal)
- Focuser compatibility: 2" and 1.25" (with adapter)
- T2 thread: integrated in the 2"/1.25" adapter
- Finderscope: 6x30 optical
- Diagonal: 1.25" mirror diagonal
- Included eyepiece: Plössl 26 mm
- Dovetail: 44 mm Vixen standard, stainless steel
- Piggyback thread: 1/4" (on cradle rings and handle)
- Solar filter: yes, included as standard
Who Is the Bresser Messier 102s OTA For?
This telescope is particularly well suited for astronomers who already own a suitable mount or tripod and are looking for a quality tube to take their observation to the next level. The f/5.9 focal ratio and 102 mm aperture are an ideal combination for visual observation of planets, the Moon, and bright deep-sky objects - globular clusters, open clusters, and brighter nebulae.
Thanks to the integrated solar filter, the Bresser Messier 102s OTA is one of the few refractors in this class that allows safe daytime observation of the Sun - tracking sunspots and monitoring activity on the surface of our star. This makes it a truly all-day observing instrument, not just a nighttime telescope.
The premium Hex focuser, T2 adapter, and piggyback holder will also appeal to beginner astrophotographers who want to capture their first images of the Moon, planets, or star fields without additional investment in basic accessories. All necessary connectors and adapters are included in the box, so the telescope is ready for imaging straight away.
Why Choose Bresser?
Bresser is a well-established German optics manufacturer with a long tradition in astronomical telescopes, microscopes, and measuring instruments. The Messier range represents Bresser's product line aimed at more demanding amateur astronomers - with an emphasis on mechanical precision, optical quality, and practical usability. The Bresser Messier Hexafoc 102s OTA is a clear example of this: a refined focuser, comprehensive accessories, and the ability to observe both the Sun and the night sky from a single tube, right from the moment you unpack it.
