Askar 80PHQ f/7.5 Quadruplet APO

Quadruplet APO Optics: A 44mm Flat Field with 2 ED Elements

The 80PHQ's optical system is a 3+1 quadruplet air-spaced design, featuring two pieces of extra-low dispersion (ED) glass. The two ED elements effectively reduce chromatic aberration and enhance clarity and sharpness, and the central RMS radius is 3um.

PHQ astrographs use an integrated lens combination rather than three main lenses plus a separate corrector in a line: the system cannot perform without any one of its lenses. This gives a more rational lens arrangement, better vignette control and superior image quality, with no separate flattener to add and space.

The 80mm f/7.5 System: A 600mm Focal Length for Deep-Sky Detail

With an 80mm aperture and 600mm focal length, the Askar 80PHQ suits a wide range of deep-sky objects. Its f/7.5 is a long focal ratio among Askar astrographs, a little longer even than the 107PHQ's f/7.

With a full-frame sensor the field is about 3.4 x 2.3 degrees, wide enough for the Heart Nebula (IC 1805), with useful scale on smaller targets such as the Dumbbell Nebula (M27).

Integrated Correction: A Native 44mm Flat-Field Image Circle

The primary advantage of the PHQ series is its built-in flat-field optical design. The Askar 80PHQ supports a 44mm image circle, large enough for full-frame sensors (24x36mm), without an additional field flattener.

You don't need to calculate the back focus within the connection limit: attach your camera and focus. With the focuser fully retracted, the limit is 115mm from the base of the M48x0.75 male thread.

4-Piece Adapter Set: M48, M54, M68, and M76 Connections

The Askar 80PHQ includes a 4-piece photographic adapter set that steps the focuser's M76×1 male thread down to M48×0.75.

• Native Focuser Thread: M76×1
• Adapter 1: M76×1 to M68×1
• Adapter 2: M68×1 to M54×0.75
• Adapter 3: M54×0.75 to M54×0.75 (extender)
• Adapter 4: M54×0.75 to M48×0.75

The final M48 adapter has an M48×0.75 filter thread inside for 2-inch filters. Askar's maximum connection figures are 115mm from M48, 135mm from M54, 155mm from M68 and 168.5mm from M76, with the focuser fully retracted.

3-Inch Rack-and-Pinion Focuser with 1:10 Dual-Speed Control

The 80PHQ has a 3-inch rack-and-pinion focuser: a smooth focusing unit with dual-speed adjustment.

It has a 1:10 fine adjustment, and the rotator is marked with precise graduations for repeatable framing.

Optional 0.76x Reducer: An f/5.7 System at 456mm

For those seeking a wider field of view and faster imaging times, Askar offers an optional 0.76x full-frame reducer for the 80PHQ, a triplet.

• Reduced Focal Length: 456mm
• Reduced Focal Ratio: f/5.7
• Image Circle: 44mm
• Back Focus: Standard 55mm

At f/5.7 the same exposure takes about 58% of the time needed at f/7.5. At 456mm a full-frame sensor covers about 4.5 x 3.0 degrees, enough for the Andromeda Galaxy (M31) or the North America Nebula (NGC 7000). The reducer has a built-in M48×0.75 2-inch filter thread.

Imaging with the 80PHQ: Full-Frame Coverage and the 44mm Circle

The 44mm image circle suits sensors from small astronomy cameras up to full-frame DSLRs and dedicated astronomy cameras.

An off-axis guider (OAG), a filter wheel or drawer and your camera fit within the connection limit from the M48 thread.

Mechanical Design: A 300mm Vixen Plate and Tool-Free Rings

A pair of clamshell-style CNC-made black tube rings hold the OTA; two locking screws loosen or tighten them without tools such as Allen wrenches. The ivory main tube has a textured coating that improves grip, with bright green dust cap, handle, knobs and decorative rings.

A multi-functional handle sits on top of the rings, and the included Askar 300mm Vixen-style dovetail plate gives room to balance.

4.7kg with Rings; 450mm to 570mm Long

Weighing just 3.9kg for the optical tube alone, and 4.7kg fully equipped with rings and dovetail, the Askar 80PHQ is a compact astrograph.

The telescope's length is configurable depending on your setup. With the dew shield retracted and photo adapters attached, it measures a compact 480mm. With the dew shield fully stretched, it is 570mm.

First Night with the 80PHQ: From Setup to First Light

Thanks to its integrated design, getting started with the Askar 80PHQ is straightforward. There's no complex spacing to calculate or extra components to install.

1. Mount the Telescope: Attach the 300mm Vixen dovetail plate to your equatorial mount and secure the telescope. Slide the tube within the rings to balance it in both axes.
2. Attach Your Camera: Use the included 4-piece adapter set, which ends in an M48 thread, to connect your camera. Ensure all connections are screwed on tightly.
3. Find Focus: Aim at a bright star. Use the coarse focus knob to get close to focus, then switch to the 1:10 fine focus knob to sharpen the star. A Bahtinov mask is highly recommended for this step.
4. Frame Your Target: Loosen the rotator lock on the focuser and rotate your camera to get the desired composition for your deep-sky object.
5. Begin Imaging: Once focused and framed, you are ready to start your exposure sequence.