Astronomy Specialist

ASKAR FRA400 F/5.6 APO REFRACTOR

$2,099.00
SKU: AS-FRA400

Askar

Apochromatic Petzval quintuplet

2.88 kg


 

The Askar FRA 400 f/5.6 is a professional apochromatic Petzval quintuplet with an aperture of 72mm and a corrected field of 44mm in diameter.

The lenses are assembled in two groups: an air-spaced triplet on the front and a  correcting doublet towards the focus. The objective lens includes two Extra Low  Dispersion glass for a superb chromatic correction.

Differently from standard ED refractors, the Askar 400 features a Petzval design that does not require to set the sensor to a specific distance to the last lens. That leaves the freedom to use any filter wheel, any off-axis guider or accessory without any worry to calculate the correct distance from the flattener. 

With a large 44mm fully corrected image circle and a focal ratio of f/5.6, this is the perfect astrograph for the advanced astrophotographer. The large rack and pinion 3" focuser has a high payload capacity, it can be rotated 360° to perfectly frame the subject and it has a reduction gear of 10:1 for precise focusing.

All the lenses are fully multi-coated and the tube is internally blackened to reduce reflections and absorb stray light. The tube is made of aluminium, the rack and pinion focusing mechanism of brass and the mechanical components are engineered to provide the best rigidity, performance and durability.


Specifications

 

Optical design

Apochromatic Quintuplet dual ED air spaced

Objective diameter

72 mm

Focal length

400

Focal ratio

f/5.6

Resolving power

1.66 arc second

Stellar limiting magnitude

11.3

Max. magnification

144 x

Light gathering power

106 times the human eye

Mount attachment

Vixen style bar

Focuser

Rack & pinion dual speed (10:1) 3" diameter

Camera connection

M68x1 male thread, M48 x 0.75 male thread, 2", 1.25" 

Backfocus

140 mm

Tube weight

2.88 kg (including tube rings and dovetail bar)

Tube length

317 mm

Tube diameter

90 mm

Dew shield diameter

100 mm

SKU

AS-FRA400

 

 

 

 

Included Items

 

  • Askar 400
  • 90 mm tube rings
  • 150 mm Vixen style dovetail bar
  • Handle on the rings
  • Adapter to 2" and 1.25"
  • Adapter from M68 to M54 male
  • Adapter from M54 to M48 male
Downloads


ZWO camera software ASKAR FRA400 manual

 

Gallery

 


 

Horsehead Nebula by Mark Button | Askar FRA400, Modded Nikon D7500, SkyWatcher Star Adventurer.

 

M20 & M8 by Mark Button | Askar FRA400, Modded Nikon D7500, ZWO Duo-Band filter

 

M20 & M8 by Mark Button | Askar FRA400, Modded Nikon D7500, ZWO Duo-Band filter.

 

 

Orion Nebula by Mark Button | Askar FRA400, Modded Nikon D7500, SkyWatcher Star Adventurer.


ASKAR FRA400 F/5.6 APO REFRACTOR.

ASKAR FRA400 F/5.6 APO REFRACTOR

$2,099.00

Optical design

Apochromatic Petzval quintuplet

Image circle

Focal ratio

f/5.6

Aperture

72 mm

Focal length

400 mm

Optical thickness

Threads

Cooled

Colour or Mono

Pixel size

Sensor dimensions

Resolution

Sensor diagonal

Quantum efficiency

Read noise

Fullwell capacity

Bit depth

FPS

Camera backfocus

Filter size

Filter size

Bandpass (FWHM)

Bandpass (FWHM)

Glass thickness

Mount type

Payload capacity

Latitude range

Dovetail saddle

Slew speed

Encoders

Periodic error correction

Counterweight shaft

Azimuth adjustment range

Internal diameter

Illuminated diameter

Compatible telescope external diameter

Weight

2.88 kg

Length

Width

Height

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