Astro-Physics 110mm f6 StarFire GTX Refractor

The Astro-Physics 110 mm f/6 StarFire GTX was designed as an uncompromising dual-purpose refractor — equally optimized for mobile astrophotography and the highest visual standards. The goal was to achieve maximum optical performance in a very compact, travel-ready optical tube assembly.

The development followed three clear guiding principles:
Aperture as large as possible while remaining airline-transportable, a fast and highly corrected triplet system for modern full-frame CMOS sensors, and outstanding visual performance with an exceptionally high polychromatic Strehl.

Thanks to its short overall length, the 110GTX fits easily into an airline carry-on compliant transport case. This makes it an ideal companion for travel, mobile use, and observing under dark skies — without compromising optical performance.

The f/6 optical design with 110 mm aperture represents the optimal balance between portability, speed, and field correction. It utilizes state-of-the-art Super-ED glass combined with two precisely matched mating elements to achieve diffraction-limited performance from deep red to deep violet.

When paired with the optional f/5 Telecompressor-Corrector (TCC), the 110GTX fully illuminates full-frame sensors (35 mm) with pinpoint stars all the way to the corners. The resulting large image circle is ideally matched to the small pixel sizes of modern CMOS sensors, delivering maximum resolution across the entire field.

For visual use, the objective has been specifically optimized for an very high polychromatic Strehl ratio in the visible spectrum — precisely matched to the sensitivity of the human eye. This ensures maximum contrast and the finest detail resolution, regardless of magnification.

Whether wide-field Milky Way scanning at low magnification or high-resolution observation of the Moon, planets, Sun, and double stars, the 110GTX delivers visual performance typically associated with significantly longer focal lengths — and does so without requiring additional corrective optics.

To achieve this high level of correction at f/6, the sensitive Super-ED element is securely embedded between two robust mating elements. This design avoids large air gaps, enables rapid thermal equilibration, ensures high collimation stability, and results in a particularly robust construction.

The ion beam–assisted multi-coatings are highly durable and nearly as hard as the glass itself.

• 3.5″ Astro-Physics precision focuser with backlash-free, grease-free drawtube and 9:1 fine reduction for precise focusing — optionally upgradeable with a motorized digital focus system
• Compact and lightweight tube assembly for maximum mobility — fully retractable, felt-lined dew shield with locking screw
• State-of-the-art multi-coating for maximum transmission, high contrast, and excellent stray light suppression
• Optional Telecompressor-Corrector (110TCC): Reduces focal length to 550 mm at f/5
• Optional 3.5″ Prime Focus Field Flattener (110FF): Provides 732 mm focal length at f/6.65 with a flat field

• Astro-Physics 110 mm f/6 StarFire GTX optical tube assembly with 3.5″ precision focuser
• Retractable dew shield and matching dust cover
• 2.7″, 2″, and 1.25″ adapters for maximum compatibility with eyepieces and accessories
• Padded transport and storage case suitable for airline carry-on travel

Tube rings and/or mounting plate are NOT included.
For a more detailed description and recommended accessories for the 110GTX, please refer to the original Astro-Physics website.

• Aperture: 110 mm (4.33″)
• Focal length: 660 mm
• Focal ratio: f/6
• Theoretical resolution: approx. 1.08 arcseconds
• Field: Corrected image circle large enough for full-frame sensors up to 50 mm diameter and beyond (especially in f/5 mode with TCC)
• Coatings: High-transmission multi-coating, >97% transmission in peak regions

• Focuser: 3.5″ Astro-Physics with 9:1 fine adjustment
• Optical tube: Robust, full aluminum construction with black interior finish
• Dew shield: Fully retractable, felt-lined with locking screw; 145 mm outer diameter
• Weight: approx. 5.45 kg (including dew shield)
• Overall length: approx. 482 mm — dew shield fully retracted; without adapters — compact and travel-friendly
• Transport case: Pelican Air Case

To expand photographic capabilities, the following optional components are available:

• 110TCC Telecompressor-Corrector: Converts the system to f/5 with 550 mm focal length and delivers pinpoint stars across the entire field
• 110FF Field Flattener: Creates an f/6.65 imaging system with 732 mm focal length, flat field, and optimal correction