Askar 50P f/3.8 Quadruplet APO Telescope

A Portable 50mm f/3.8 Astrograph for Wide-Field Imaging

The Askar 50P is purpose-built for astrophotographers who need a compact, high-speed instrument for capturing vast celestial landscapes. It combines a 50mm aperture for resolving fine detail with a wide 190mm focal length, making it ideal for framing the largest nebulae, star clusters, and Milky Way star fields. Its light weight suits portable imaging rigs.

The 50P is well-suited for both astrophotography and use as a guide scope: with the dovetail plate removed, the base underneath acts as a finderscope platform, so the 50P can ride on a main telescope as a guide scope.

Quadruplet Petzval APO Optics with SD Glass

At the heart of the Askar 50P is a four-element Petzval APO objective lens. This sophisticated design uses four lenses to achieve a high degree of correction for optical aberrations. One of the elements is made from Super-low Dispersion (SD) glass, which significantly reduces chromatic aberration (the false color fringing seen around bright stars in simpler lens designs). Askar adds that the rear two elements are cemented.

The Petzval layout is unique because it incorporates the field-flattening elements directly into the main optical design. This is a significant advantage over standard doublet or triplet refractors, which require a separate, carefully spaced flattener or reducer to achieve a sharp field for imaging. With the 50P, the field is corrected internally, simplifying your imaging train and eliminating potential sources of tilt or spacing error.

The f/3.8 Advantage for Short Exposures

The 50P's f/3.8 focal ratio is its defining feature. This extremely "fast" optical system gathers light at a much higher rate than telescopes with slower focal ratios like f/5 or f/7. For an imager, this means you can capture the same amount of signal on a faint nebula in a fraction of the time. Shorter exposures reduce the demands on your mount's tracking accuracy, minimize the impact of passing clouds or satellites, and allow you to collect more data in a single night.

This speed suits imaging faint hydrogen-alpha regions, expansive dark nebulae, and other challenging deep-sky objects. It’s also ideal for creating large, multi-panel mosaics of the Milky Way, as you can cover huge swaths of sky quickly without needing hours of exposure time for each panel.

Flat-Field Imaging for APS-C Sensors

The integrated Petzval corrector delivers a sharp, flat image circle that supports APS-C format sensors and is specifically optimized for 1-inch sensors. Once imaging accessories are attached, users can begin shooting as soon as the OTA is focused.

• No Flattener Needed: You do not need to purchase or calculate the spacing for an external field flattener. Simply attach your camera and focus.

55mm Back Focus and M48x0.75 Camera Connection

Integrating your camera with the Askar 50P is straightforward. The telescope terminates in a standard M48x0.75 male thread, and the rear M48 adapter has a built-in 2-inch filter thread. The recommended connection length is 55mm.

Askar supports a connection range of 50mm to 65mm (the maximum allowed distance from the M48x0.75 male thread base is 65mm). The manual provides a clear diagram showing the focal plane, ensuring you can set up your equipment accurately.

Focusing Ring with 15mm Travel and MXL Teeth

The Askar 50P focuses with an integrated single-speed focusing ring (a helical focus ring) with 15mm of travel. At the rear, a rotating scale with a locking screw lets you set the camera angle.

For automated imaging, the focuser ring is equipped with standard MXL-type teeth. This makes the ring compatible with electronic focusers; the optional Askar 50P AF Kit is designed for the 50P and can be used with almost all brands of electronic focusers.

Mechanical Design: Dew Shield, Rings, and Mounting

The Askar 50P is built with practical use in mind.

• Reversible Bayonet Lens Hood: The quick-release lens hood extends during use to block stray light (total length 147mm contracted, 182mm stretched) and folds back for compact storage. With the dust cap it protects the objective.
• Multi-Function Ring and Handle: The telescope is held in a sturdy, integrated tube ring that also functions as a carrying handle. Its top slot complies with the Arca-Swiss standard, so the 50P can mount directly on a tripod via a quick-release plate, and multiple standard M4 threaded holes are provided.
• Dual Finder Bases: Two finder scope bases are integrated into the sides of the ring, allowing you to mount a guide scope, finder, or other accessories.
• 160mm Dovetail Plate: The dovetail plate is 160mm long; when it is removed, the base underneath acts as a finderscope platform.

Portability: A 1.4kg, 147mm Imaging Platform

Weighing just 1.4kg (including the ring and dovetail) and measuring only 147mm in length with the dew shield retracted, the Askar 50P is exceptionally compact and lightweight. This small footprint makes it an ideal instrument for air travel to dark sky locations or for hikers who want to carry an imaging rig into remote areas. It places minimal demand on a mount.

First Light: A Step-by-Step Guide

Getting started with the Askar 50P is simple, thanks to its integrated design.
1. Mounting: Attach the 160mm dovetail plate to your mount, or use the Arca-Swiss slot on top of the handle with a quick-release plate.
2. Camera Attachment: Connect your camera to the rear M48x0.75 male thread. Use a 55mm connection length from the thread's base, within the supported 50mm to 65mm range.
3. Balancing: With the camera attached, slide the dovetail plate forward or backward in the mount's saddle until the telescope is balanced.
4. Focusing: Aim at a bright star. Rotate the helical focusing ring until the stars are as small and sharp as possible. Use a Bahtinov mask for critical focus. Use the rotating scale and its locking screw to set the camera angle.
5. Imaging: You are now ready to begin your imaging session. The natively flat field means you can start capturing your target without any additional optical adjustments.