Skip to content
  • 🎁 Treat your loved ones with our 🎁Gift collection🎁 and snap sales!🎁
  • 🎁 Treat your loved ones with our 🎁Gift collection🎁 and snap sales!🎁
Telescope Sales ShopTelescope Sales Shop
    • No products in the cart.

      Return to shop

  • Cart

    No products in the cart.

    Return to shop

  • Telescope accessories
    • Parts & spares
    • Straylight and glare shields
    • Finder
    • Prisms & Diagonal mirrors
    • Transport & storage
    • Alignment accessories
    • Focusers
    • Cables & power supplies
    • Dew shields & Ventilation
    • Barlow & Erecting Lenses
    • Miscellaneous
    • Adaptors
    • Binocular viewers
  • Binoculars
    • Accessories
    • Instruments
  • Filters
    • L-RGB Filters
    • Planetary & Comet Filters
    • Pass Filters
    • Moon filters & Polarizing filters
    • Nebulae filters
    • Filter wheels & Filter sliders
    • Other
    • Blocking Filters
  • Eyepieces
  • Telescopes
  • Mountings & accessories
    • Mountings
    • Tripods & Mounts
    • Tube clamps
    • Column Stands & Extensions
    • Mounting plates and rails
    • Pole finder
    • Miscellaneous
    • Motor- & Goto-Upgrades
    • Controls
    • Counterweights
    • Equatorial wedges
Telescopes
Sale!
William Optics Apochromatic Refractor AP 81/559 ZenithStar 81 Red OTA
William Optics Apochromatic Refractor AP 81/559 ZenithStar 81 Red OTA - Image 2
William Optics Apochromatic Refractor AP 81/559 ZenithStar 81 Red OTA - Image 3
William Optics Apochromatic Refractor AP 81/559 ZenithStar 81 Red OTA - Image 4
William Optics Apochromatic Refractor AP 81/559 ZenithStar 81 Red OTA - Image 5
William Optics Apochromatic Refractor AP 81/559 ZenithStar 81 Red OTA - Image 6
William Optics Apochromatic Refractor AP 81/559 ZenithStar 81 Red OTA - Image 7
William Optics Apochromatic Refractor AP 81/559 ZenithStar 81 Red OTA - Image 8
William Optics Apochromatic Refractor AP 81/559 ZenithStar 81 Red OTA - Image 9
William Optics Apochromatic Refractor AP 81/559 ZenithStar 81 Red OTA - Image 10
William Optics Apochromatic Refractor AP 81/559 ZenithStar 81 Red OTA - Image 11
William Optics Apochromatic Refractor AP 81/559 ZenithStar 81 Red OTA - Image 12
William Optics Apochromatic Refractor AP 81/559 ZenithStar 81 Red OTA - Image 13

William Optics Apochromatic Refractor AP 81/559 ZenithStar 81 Red OTA

$359.00 Original price was: $359.00.$96.99Current price is: $96.99.

Buy Now
SKU: YXN0C 62022 Category: Telescopes
  • Safeguard Your Shopping Experience
  • Quality You Can Trust
  • Experience Quality, Shop with Us
  • Multiple safe payment methods
Browse
  • Binoculars
    • Accessories
    • Instruments
  • Eyepieces
  • Filters
    • Blocking Filters
    • Filter wheels & Filter sliders
    • L-RGB Filters
    • Moon filters & Polarizing filters
    • Nebulae filters
    • Other
    • Pass Filters
    • Planetary & Comet Filters
  • Mountings & accessories
    • Column Stands & Extensions
    • Controls
    • Counterweights
    • Equatorial wedges
    • Miscellaneous
    • Motor- & Goto-Upgrades
    • Mounting plates and rails
    • Mountings
    • Pole finder
    • Tripods & Mounts
    • Tube clamps
  • Telescope accessories
    • Adaptors
    • Alignment accessories
    • Barlow & Erecting Lenses
    • Binocular viewers
    • Cables & power supplies
    • Dew shields & Ventilation
    • Finder
    • Focusers
    • Miscellaneous
    • Parts & spares
    • Prisms & Diagonal mirrors
    • Straylight and glare shields
    • Transport & storage
  • Telescopes
  • Description
  • Additional information
  • Reviews (0)

Product description

More about the series ZenithStar…

The William Optics’ ZenithStar range consists of compact yet very high-quality apochromats which are ideally suited for use with a DSLR camera. With these, you can capture excellent wide-angle images of large star fields. Combined with an optional flattener, these provide a corrected image field with a diameter of 45 millimetres right up to the edges.

The lightweight and compact ZenithStar apochromat and a DSLR fit well on a photography mount, such as the Skywatcher Star Adventurer or the iOptron Star Tracker – a simple, lightweight astrophotography system.

The ZS81 is an F/6.9 FPL53 Doublet air-spaced APO with a CNC machined ultra-high precision lens cell, F/5.5 with a optional x0.8-Flattener. It comes wit a 2.5”R&P Ultra robust focuser with 1:10 dual speed: a treat to use during astrophotography. No image shifting! Heavy duty: perfect for your accessories.

It comes with a innovative Bahtinov Mask Cover!

Despite its 81mm objective, the scope is still very compact and solid. Many airlines will accept it as carry-on luggage! Perfect size for serious observations of deep sky objects and planets. Solar observations possible with proper additional equipment.

This beautiful scope is everything you always wanted in a refractor, starting from extreme sharpness for clear details, and APO color correction.

It is not only important which telescope you buy, but also where you buy it.

We provide extra help:

  • We are a leading telescope dealer and know these instruments like the back of our hands.
  • We are always very happy to offer our assistance after your purchase, should you encounter any problems with your telescope’s setup or operation.
  • Our ‘Telescope Basics’ booklet – an 80-page beginner’s guide for our telescopes – is provided free of charge with every telescope we sell.
Type

Refractor

Carrying handle

yes

Advanced

yes

Beginners

no

Sun

no (Only with appropriate Sun filter)

Nebulae & galaxies

yes

Nature Observation

no

Moon & Planets

yes (very good)

Astrophotography

yes (very good)

Colour

red

Series

ZenithStar ZenithStar High-quality apochromats for astrophotography.Click to read more…

Dew Shield

yes

Prism rail

Arca-Swiss & Vixen-Style

Tube clamps

yes

Miscellaneous

Bahtinov focus mask

Carry case

yes

Mounting type

no mount

Aperture(mm)

81

Free aperture(mm)

64

Connecting threaded socket (camera-side)

M63

Gear reduction

1:10 Fine movement

Connection ( to eyepiece)

2

Type of build

OTA OTA An OTA is an optical tube without a mount. It is short for optical tube assembly.Click to read more…

lens design

Doublet Doublet A refractor with two lenses. Compared to an achromat, it displays significantly less chromatic aberration and more contrast.Click to read more…

Tube weight(kg)

3,5

Carrying length(mm)

456

Max. useful magnification

162

Light gathering capacity

130

Limit value(mag)

11,3

Resolving capacity

1,70

Aperture ratio(f/)

6,9

Focal length(mm)

559

Observatories

no

Reviews

There are no reviews yet.

Be the first to review “William Optics Apochromatic Refractor AP 81/559 ZenithStar 81 Red OTA” Cancel reply

Related products

Sale!
Skywatcher Telescope AC 102/1000 EvoStar BD EQ3-2
Quick View

Telescopes

Skywatcher Telescope AC 102/1000 EvoStar BD EQ3-2

$355.00 Original price was: $355.00.$97.99Current price is: $97.99.
Sale!
TS Optics Apochromatic Refractor AP 76/342 EDPH Flatfield OTA
Quick View

Telescopes

TS Optics Apochromatic Refractor AP 76/342 EDPH Flatfield OTA

$394.00 Original price was: $394.00.$98.99Current price is: $98.99.
Sale!
TS Optics Apochromatic Refractor AP 80/352 Imaging Star OTA
Quick View

Telescopes

TS Optics Apochromatic Refractor AP 80/352 Imaging Star OTA

$345.00 Original price was: $345.00.$95.99Current price is: $95.99.
Sale!
William Optics Apochromatic Refractor AP 81/559 ZenithStar 81 Gold OTA
Quick View

Telescopes

William Optics Apochromatic Refractor AP 81/559 ZenithStar 81 Gold OTA

$346.00 Original price was: $346.00.$95.99Current price is: $95.99.
Sale!
TS Optics Telescope N 76/700 Starscope AZ-1
Quick View

Telescopes

TS Optics Telescope N 76/700 Starscope AZ-1

$151.00 Original price was: $151.00.$96.99Current price is: $96.99.
Sale!
TS Optics Apochromatic Refractor AP 102/1122 ED OTA
Quick View

Telescopes

TS Optics Apochromatic Refractor AP 102/1122 ED OTA

$363.00 Original price was: $363.00.$97.99Current price is: $97.99.
Sale!
Vixen Apochromatic Refractor AP 103/825 ED AX103S Sphinx SXP2 Starbook Ten GoTo
Quick View

Telescopes

Vixen Apochromatic Refractor AP 103/825 ED AX103S Sphinx SXP2 Starbook Ten GoTo

$346.00 Original price was: $346.00.$95.99Current price is: $95.99.
Sale!
Skywatcher Dobson Telescope N 203/1200 Skyliner FlexTube BD DOB GoTo
Quick View

Telescopes

Skywatcher Dobson Telescope N 203/1200 Skyliner FlexTube BD DOB GoTo

$392.00 Original price was: $392.00.$98.99Current price is: $98.99.
MY ACCOUNT
  • Cart
  • Checkout
  • My account
  • Wishlist
ABOUT US
  • About Us
  • FAQ
  • Returns & Exchanges
  • Delivery
  • Contact Us
LEGAL
  • Privacy Policy
  • Payment Method
  • Shipping Policy
  • Term and Conditions
Signup for Newsletter

Sign up for exclusive offers, original stories, events and more.

    Copyright 2025 © www.usopticscopes.com
    • Telescope accessories
      • Parts & spares
      • Straylight and glare shields
      • Finder
      • Prisms & Diagonal mirrors
      • Transport & storage
      • Alignment accessories
      • Focusers
      • Cables & power supplies
      • Dew shields & Ventilation
      • Barlow & Erecting Lenses
      • Miscellaneous
      • Adaptors
      • Binocular viewers
    • Binoculars
      • Accessories
      • Instruments
    • Filters
      • L-RGB Filters
      • Planetary & Comet Filters
      • Pass Filters
      • Moon filters & Polarizing filters
      • Nebulae filters
      • Filter wheels & Filter sliders
      • Other
      • Blocking Filters
    • Eyepieces
    • Telescopes
    • Mountings & accessories
      • Mountings
      • Tripods & Mounts
      • Tube clamps
      • Column Stands & Extensions
      • Mounting plates and rails
      • Pole finder
      • Miscellaneous
      • Motor- & Goto-Upgrades
      • Controls
      • Counterweights
      • Equatorial wedges
    • Login

    Login

    Lost your password?

    Register

    Your personal data will be used to support your experience throughout this website, to manage access to your account, and for other purposes described in our privacy policy.