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Telescopes > William Optics > Cat > William Optics Apochromatic refractor AP 51/250 Black&White Cat 51 OTA
Product no.: 77438

Apochromatic refractor AP 51/250 Black&White Cat 51 OTA

$ 1,180.00 incl. VAT plus shipping costs
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  • Integrated flattener
  • 4-lens, multi-coated Petzval design
  • Colour-true and sharp images up to full-frame sensors
  • Extremely handy, lightweight and superbly crafted

Product description

More about the series Cat...

In brief:

  • Integrated flattener
  • 4-lens, multi-coated Petzval design
  • Colour-pure and sharp images up to full-frame sensors
  • Extremely handy, lightweight and superbly crafted Apo

The AP 51/250 lens is an impressive combination of small size, affordable price and outstanding optical quality, and is aimed at all astrophotographers and nature photographers. The core of the optical design is the Petzval design consisting of 4 elements in 3 groups, using FPL53 and FPL51 glass. The result is a colour-pure, corrected image field with a diameter of over 44 millimetres – ideal for full-frame cameras! The fast aperture ratio of f/4.9 allows for short exposure times.

An M48 thread is provided for connecting the camera. Suitable T2 adaptors can be found under "Recommended accessories". Focusing is helical, i.e. by turning the easy-grip ring on the tube. This means that even heavy cameras are no problem.

The 110 mm long prism rail offers three connection options: for screwing with a photo thread or for sliding in according to Arca-Swiss or Vixen standards. With these three options, it should be no problem to attach the telescope to all common photo tripods, camera mounts or astronomical mounts.

The scope also comes with a protective nylon carrying bag and the Bahtinov mask familiar from the RedCat.

The Black & White version of the popular RedCat 51 is limited and only available in small quantities from the manufacturer. We will deliver while stocks last!

It not only matters which telescope you buy but also where you buy it. Our additional services:

  • We are a leading telescope dealer and know the devices we sell. Our customer service team will gladly help you after your purchase if you have problems with assembly or operation.
  • We provide a copy of the 80-page Telescope ABC beginners handbook with every telescope.

Our expert comment:

The handle shown in the photos (WO Handle Bar) is optional and not included in the standard delivery!

(Jan Ströher)

Specifications

Optics


Type
Refractor
Type of build
Apochromat
Aperture (mm)
51
Focal length (mm)
250
Aperture ratio (f/)
4,9
Resolving capacity
2,71
Limit value (mag)
10,3
Light gathering capacity
50
Max. useful magnification
102
Tube weight (kg)
1,5
Carrying length (mm)
225
Tube material
Aluminium
Coating
multiple
dew cap diameter (mm)
80
lens design
Quadruplet

Focuser


Tilting Adaptor
yes
Type of build
Helical
Connecting threaded socket (camera-side)
M48
Backfocus (mm)
59,7
Free aperture (mm)
44
Adjustment range (mm)
33
Rotating
yes

Mount


Type of build
OTA
Mounting type
no mount

Included accessories


Dew Shield
yes
Carry case
yes
Miscellaneous
Bahtinov focus mask
Prism rail
Arca-Swiss & Vixen-Style
Thread for camera tripod
1/4
Corrector
integrated

General


Series
Cat
Colour
white

Area of application


Moon & Planets
yes
Nature Observation
yes
Nebulae & galaxies
yes
Sun
no (Only with appropriate Sun filter)
Astrophotography
yes (very good)

Recommended for


Beginners
no
Advanced
yes
Observatories
no

Product safety

Manufacturer: William Optics Co. Ltd, TW, [email protected]
Responsible person: NIMAX GmbH, Otto-Lilienthal-Str. 9, 86899 Landsberg am Lech, DE, [email protected]

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*All prices include VAT plus shipping costs.

William Optics Apochromatic refractor AP 51/250 Black&White Cat 51 OTA
William Optics Apochromatic refractor AP 51/250 Black&White Cat 51 OTA
William Optics Apochromatic refractor AP 51/250 Black&White Cat 51 OTA
William Optics Apochromatic refractor AP 51/250 Black&White Cat 51 OTA
William Optics Apochromatic refractor AP 51/250 Black&White Cat 51 OTA
William Optics Apochromatic refractor AP 51/250 Black&White Cat 51 OTA
William Optics Apochromatic refractor AP 51/250 Black&White Cat 51 OTA
William Optics Apochromatic refractor AP 51/250 Black&White Cat 51 OTA
William Optics Apochromatic refractor AP 51/250 Black&White Cat 51 OTA

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