Askar FRA400 The Askar FRA400 is a 72 mm f/5.6 astrograph with a 400 mm focal length. Its five-element Petzval-like design uses two ED elements and provides a 44 mm image circle for full-frame photography.
Manufacturer model: Askar FRA400 · Specifications checked against manufacturer data on 2026-11-04
The Askar FRA400 is a 72 mm f/5.6 astrograph with a 400 mm focal length. Its five-element Petzval-like design uses two ED elements and provides a 44 mm image circle for full-frame photography.
Built-in field correction
The native optical design incorporates field flattening. There is no additional flattener to space at 55 mm: fit the imaging train within the available connection allowance and focus the telescope. Askar publishes 140 mm from the M68×1 rotator reference to the focal plane.
Focusing and visual accessories
A 3-inch rack-and-pinion focuser provides 1:10 fine adjustment and a 360° rotator. The rear assembly offers M68×1, a conical M68-to-M48 adapter and 2-inch/1.25-inch visual connections. A retractable hood and multifunction tube rings provide practical mounting options.
Native and reduced configurations
The standard package includes rings, handle, dovetail and conical adapter. Askar lists 317 mm overall length, 2.56 kg OTA and 2.88 kg with rings and dovetail. The separately available matching reducer changes the system to approximately f/3.9 and requires its own specified camera spacing.
The detailed description and technical table identify a quintuplet dual-ED design; a promotional icon incorrectly says quadruplet. Native 140 mm connection allowance is measured from the M68×1 rotator reference, not a mandatory 55 mm reducer spacing.
Additional specifications
Manufacturer accessories
A pair of tube rings, a handle, a dovetail plate, a M68-M48 conical adapter , an inspection list, a manual
80164
Scheda tecnica
Apertura
72mm
Back focus
140mm (from the end of rotator M68x1 thread)
Paraluce
Retractable
Correzione di campo
Integrated Petzval-like system
Rapporto della messa a fuoco fine
1:10
Focale
400mm
Rapporto focale
f/5.6
Focheggiatore
3-inch rack-and-pinion
Cerchio d'immagine
44mm
Modello
FRA400
Schema ottico
Quintuplet dual ED air-spaced APO
Riduttore opzionale
Matching FRA400/FRA500 f/3.9 full-frame reducer; sold separately
Peso del tubo ottico
2.56kg
Lunghezza totale
317mm
Adattatore posteriore
M68×1 male thread, 2" adapter/1.25" adapter
Rotatore
360°
Peso con anelli e coda di rondine
2.88kg
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Askar FRA400 The Askar FRA400 is a 72 mm f/5.6 astrograph with a 400 mm focal length. Its five-element Petzval-like design uses two ED elements and provides a 44 mm image circle for full-frame photography.
Manufacturer model: Askar FRA400 · Specifications checked against manufacturer data on 2026-11-04