Astro-Tech 110EDA f/4.8 refractor OTA

The innovative Astro-Tech 110mm f/6 apochromatic triplet uses a lens of extra-low dispersion FCD-100 ED glass, flanked by two carefully chosen mating lenses of premium optical glass. The trio delivers crisp, high-fidelity wide-field images of celestial objects. The views are unmarred by the faint but annoying halo of unfocused violet light (chromatic aberration) often seen around bright stars and solar system objects in other large aperture fast focal ratio doublet and triplet refractors. Now here is where it gets interesting.  A separate thread-on four element reducer/field flattener built in the camera angle adjuster drops the scope speed to f/4.8 and provides pin-point star images across the entire 44mm image circle for superb astrophotography.  The scope will ship in the f/4.8 configuration as the standard setup.

The 110mm Astro-Tech 110EDA triplet utilizes the most modern optical glasses and fabricating techniques to deliver the ultimate in small aperture high-fidelity astronomical observing and imaging. Each lens element is individually inspected for purity and absence of striations and other image-degrading imperfections. Each element is then pitch polished to exacting standards of optical fabrication and performance by highly skilled opticians and tested on an optical laser bench to rigidly controlled optical standards. The entire system, including the reducer/field flattener, is placed on an optical test bench for final collimation and alignment prior to being packed up for shipment.  The result is a high-quality, diffraction-limited optical system performing to the theoretical limits of its aperture - one that will give you years of imaging and visual observing satisfaction.

Features of this Astro-Tech 110mm refractor . . .

Apochromatic ED triplet refractor optics: 110mm (4.33") aperture, 660mm focal length at the native f/6 focal ratio,  528mm focal length when used in conjunction with the reducer/field flattener providing an f/4.8 system. The triplet objective lens uses mating elements of premium optical glass. The center ED element is precision-polished from high grade FCD-100 (Extra-low Dispersion) glass.

Fully multicoated optics: Each air-to-glass surface in the Astro-Tech 110EDA triplet objective lens has high transmission antireflection multicoatings on all air-to-glass surfaces for high light transmission, minimal light scatter, and excellent contrast.

Retractable dew shield: The aluminum dew shield retracts to allow the scope to fit into its hard carrying case, and extends when the scope is in use. The dew shield slows the formation of dew on the lens in cold weather to extend your undisturbed observing time. It also improves the contrast, similar to the effect of the lens shade on a camera lens, when observing during the day or when there is excessive ambient light at night, such as a neighbor's backyard security light. 

Thread-on four element reducer/field flattener: Imaging is the name of the game with this instrument.  While it will be great for visual work, its inherent design is to gather photons.  The four element reducer/field flattener drops the f ratio from f/6 to a blazing f/4.8.  The reducer/field flattener is housed in the camera angle adjuster housing and can be threaded onto the optical tube to transform your scope into an exceptional wide-field imaging Instrument. The instrument will ship standard in the imaging configuration. Using optical grade glass and multicoatings on all air-to-glass lens surfaces, the field flattener provides sharp, in-focus stars across a large fully-illuminated 44mm image circle. This is ideal for DSLR cameras, CMOS cameras, and for virtually all CCD cameras. Back focus is 55mm. The rear of the camera angle adjuster/reducer/field flattener is threaded to accept 48mm camera attachments.

Dual speed 3.2" rack and pinion focuser: The precision-made and mechanically ultra-smooth, backlash-free, rack and pinion focuser has a giant 3.2" diameter drawtube . This focuser offers dual-speed focusing and has an engraved focusing scale. There are two coarse focusing knobs. The right knob has a smaller concentric knob with 10:1 reduction gear microfine focusing over the full focuser travel. This provides exceptionally precise image control during a critical imaging session. The large focus knobs have ribbed gripping surfaces so they are easy to operate, even while wearing gloves or mittens in cold weather. A lock knob lets you adjust the tension on the drawtube to accommodate varying eyepiece/photo accessory loads, as well as firmly lock in a photographic focus.  The single coarse knob is easily removable so one can attache an electric focuser to aid with imaging.

Mounting rings and dovetail: The Astro-Tech 110EDA has dual hinged split-ring tube rings to fit the aluminum optical tube. They are bolted to a Vixen-style dovetail that fits directly into the dovetail slot on the head of many of the most popular medium to heavy capacity German equatorial mounts.  There is also a carry handle attached to the top of the rings to aid in mounting accessories as well as carrying the scope around.