Askar 111F 111mm f/6.9 Flat-Field Quadruplet APO Refractor

A 4.4-inch flat-field refractor that frames galaxies and nebulae and doubles as a visual scope

The Askar 111F Flat-Field is a 111mm f/6.9 air-spaced quadruplet APO refractor with one ED element, three lenses up front and one at the rear. It covers a full-frame sensor with no added flattener and comes with a 3" dual-speed rack-and-pinion focuser, a 360° rotator, a retractable dew shield, an internal baffle against stray light, two finder bases at the focuser and a handle with a third. It sits between the portable 91F and the big 131F: enough aperture and focal length for galaxies, still a manageable size to carry out to the yard.

Key specs: 111mm aperture · 766mm focal length · f/6.9 · quadruplet air-spaced APO with 1 ED element · 44mm image circle, no flattener needed · 3" rack-and-pinion focuser, 1:10 fine focus · 6.76kg (14.9lb) with rings, handle and 300mm Vixen plate

What you can image and see

• Galaxies: M81 and M82 together, the Triangulum Galaxy (M33), the Whirlpool (M51), the Leo Triplet and the bright core of the Andromeda Galaxy with M32.
• Nebulae: the Horsehead and Flame Nebulae in one frame, the Orion Nebula and Running Man, the Crescent Nebula, the Eagle Nebula, the Jellyfish Nebula (IC 443) and the Pacman Nebula.
• Clusters and planetary nebulae: the Hercules Cluster (M13), the Dumbbell Nebula (M27) and the Helix Nebula.
• At the eyepiece: Saturn's rings, Jupiter's belts and moons, lunar detail at high power, and the whole Pleiades cluster at low power.

Fields of view at 766mm: 2.69° × 1.80° with a full-frame sensor, 1.76° × 1.17° with an APS-C camera such as the ASI2600MC Pro (1.01″ per pixel), and 0.85° × 0.85° with the ASI533MC Pro.

How it works

Imaging: the included photographic extension tubes thread onto the focuser and end in an M54 × 0.75 or M48 × 0.75 male thread, with a 2" filter thread built in. Because the 111F flattens its own field, spacing isn't critical: the sensor can sit anywhere from 43 to 73mm behind the M48 thread (61 to 91mm behind the M54 thread) and still reach focus. That leaves room for a filter drawer, filter wheel or off-axis guider in front of the camera.

Visual: use the built-in 2" or 1.25" adapter with a diagonal and eyepiece. A 2" 35mm wide-field eyepiece gives about 22x and a field near 3°; a 10mm eyepiece gives about 77x.

Focusing and framing: the dual-speed focuser's 1:10 fine knob has a protective cap, and the graduated 360° rotator turns the camera to frame a target. A ZWO EAF mounts in place of the coarse focus knob with a 5 to 6mm flexible coupling, as Askar's assembly diagram shows.

Mounting: the 300mm Vixen-style plate has 1/4" and 3/8" threaded holes, fits standard Vixen saddles and can go straight onto a heavy photo tripod for daytime use.

What to add for the best results

• A mount (required): the ZWO AM5N with TC40 tripod carries 15kg (33lb) without a counterweight, plenty for the 111F, a camera and a guider.
• A camera: the ZWO ASI2600MC Pro, the ASI2600MC Air with built-in ASIAIR and guider, or the ASI2600MM Pro with ZWO 7nm SHO filters for mono narrowband.
• Guiding: the Askar 52mm Super ED guide scope on a finder base with an ASI220MM Mini, or a ZWO OAG in the imaging train.
• Autofocus: the ZWO EAFN or EAF Pro.
• Filters: a 2" Askar Colour Magic C1 (Hα + OIII) threads into the extension tube, or use a ZWO M54 filter drawer to swap filters without removing the camera.
• For visual use: a 2" diagonal such as the Explore Scientific 2" diagonal and eyepieces from our eyepiece collection.

Askar F-series comparison

All five share the same 44mm full-frame image circle and self-flattened quadruplet design. See all Askar telescopes.

What's in the box

• Askar 111F Flat-Field optical tube with retractable dew shield and front cap
• Pair of tube rings with handle bar
• 300mm Vixen-style dovetail plate
• Set of photographic adapters (extension tubes with M54 and M48 threads and a 2" filter thread)
• 1.25" and 2" visual adapters

A mount, camera, diagonal, eyepieces and finder are sold separately.

Askar 111F FAQ

Is the 111F good for beginners?

For visual observing, yes: it's a straightforward refractor that needs no collimation. For imaging, it's a good second telescope. At 766mm, guiding has to be decent, so if you're just starting, the 91F or 71F is more forgiving.

111F or 91F?

The 111F gathers about 49% more light and has 26% more focal length for galaxies and smaller nebulae. The 91F weighs 2.24kg less, is 178mm shorter and frames bigger targets, such as the whole Andromeda Galaxy on a full-frame camera.

111F or 131F?

The 131F adds aperture and reaches 983mm for small targets, but it weighs 9.4kg and needs a Losmandy saddle. The 111F is the one most mid-size mounts handle comfortably.

Can I see Jupiter and Saturn?

Yes. With a 2" diagonal and a short eyepiece, the 111F shows Saturn's rings and Jupiter's belts and moons sharply, and you can push to about 200x on steady nights.

Do I need a flattener or reducer?

No flattener is needed. Askar makes a 0.74x reducer for the 111F that brings it to about 567mm for a wider, faster field; ask us about availability.

Specifications