Telescopes > William Optics > Cat > William Optics Apochromatic refractor AP 51/250 SpaceCat WIFD OTA

$William Optics Apochromatic refractor AP 51/250 SpaceCat WIFD OTA$ $William Optics Apochromatic refractor AP 51/250 SpaceCat WIFD OTA$ $William Optics Apochromatic refractor AP 51/250 SpaceCat WIFD OTA$ $William Optics Apochromatic refractor AP 51/250 SpaceCat WIFD OTA$ $William Optics Apochromatic refractor AP 51/250 SpaceCat WIFD OTA$ $William Optics Apochromatic refractor AP 51/250 SpaceCat WIFD OTA$ $William Optics Apochromatic refractor AP 51/250 SpaceCat WIFD OTA$ $William Optics Apochromatic refractor AP 51/250 SpaceCat WIFD OTA$ $William Optics Apochromatic refractor AP 51/250 SpaceCat WIFD OTA$ $William Optics Apochromatic refractor AP 51/250 SpaceCat WIFD OTA$

Product no.: 83498

Apochromatic refractor AP 51/250 SpaceCat WIFD OTA

Name: William Optics Apochromatic refractor AP 51/250 SpaceCat WIFD OTA
Brand: William Optics
Price: 1180 USD

$ 1,180.00 incl. VAT plus shipping costs

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Express shipment possible for delivery tomorrow, 18.12.2025!

Delivery possible before Christmas (European destinations) - when you order by 18.12.!
Right of return up to January 31 2026!

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Product description

More about the series Cat...

The AP 51/250 optics are an impressive combination of small size, affordable price and outstanding optical quality, and are aimed at all astrophotographers and nature photographers. At the heart 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 comes with a protective nylon carrying bag and a specially designed Bahtinov mask. This mask helps with focusing and is permanently integrated into the lens attachment.

Specifications

Optics

Type

Refractor

Type of build

Apochromat

Aperture (mm)

Focal length (mm)

250

Aperture ratio (f/)

4,9

Resolving capacity

2,71

Limit value (mag)

10,3

Light gathering capacity

Max. useful magnification

102

Tube weight (kg)

2,4

Tube length (mm)

346

Tube material

Aluminium

Coating

multiple

Tube construction

Full tube

dew cap diameter (mm)

lens design

Quadruplet

Focuser

Tilting Adaptor

yes

Type of build

Helical

Connecting threaded socket (camera-side)

M48

Backfocus (mm)

59,7

Free aperture (mm)

Adjustment range (mm)

0-23

Rotating

yes

Mount

Type of build

OTA

Mounting type

no mount

Included accessories

Dew Shield

yes

Carry case

yes

Miscellaneous

Focusing Mask

Prism rail

Arca-Swiss & Vixen-Style

Thread for camera tripod

1/4

Corrector

integrated

General

Series

Cat

Colour

silver

Area of application

Astrophotography

yes (very good)

Moon & Planets

yes

Nature Observation

Nebulae & galaxies

yes

Sun

yes (Only with appropriate Sun filter)

Recommended for

Beginners

Advanced

yes

Observatories

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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]

Product safety

$William Optics Apochromatic refractor AP 51/250 SpaceCat WIFD OTA$

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