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Telescopes > William Optics > Cat > William Optics Apochromatic refractor AP 51/250 RedCat 51V2 OTA

Product description

More about the series Cat...

The AP 51/250 refractor is an impressive combination of compact size, attractive price and outstanding optical quality which is suitable for all astro- and nature photography. At the heart of the optical set-up is the Petzval design comprising four elements in three groups in which FPL53 and FPL51 glass has been utilised. The result is a colour-rich corrected image field with a diameter of more than 44 mm - perfect for full-frame cameras. The fast focal ratio of f/4.9 allows short exposure times.

For camera connection there is a M48 thread. Appropriate T2 adapters can be found under “recommended accessories”. Focusing is helical - so by twisting the textured ring on the telescope body even heavy cameras are no problem.

The 110mm long dovetail bar offers three connection alternatives; screw connection with a photo thread, Arca Swiss or Vixen standard fittings. With these three options it should be no problem to connect this telescope to all the usual photo tripods, photo mounts or astronomical mounts.

Not only is a protective nylon carrying case included, but also a specially devised Bahtinov mask. This mask helps with focusing and is built into the lens cap.

A telescope such as the RedCat 51 is ideal for photographers who are interested in the night sky and also animal photography.

With the RedCat 51 you are not only investing in impressive optical performance, but you will also be thrilled by the durable and beautiful finish William Optics has achieved.

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.

Our expert comment:

The RedCat 51 is probably one of William Optics’ most loved apochromats and not without good reason. It delivers perfect astrophotos of deep-sky objects and is easily transportable due to its small size.

(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
Tube length (mm)
225
Tube material
Aluminium
Coating
multiple
Tube construction
Full tube
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
Carrying bag
yes
Miscellaneous
Bahtinov focus mask
Prism rail
Arca-Swiss & Vixen-Style
Corrector
integrated

General


Series
Cat
Colour
red

Area of application


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

Recommended for


Beginners
no
Advanced
yes
Observatories
no

Recommended accessories

Telescope accessories (8)
Diagonal prism

William Optics Diagonal prism RedCat 90° 1,25"

$ 174.00*
Eyepieces (2)
Reticle eyepieces

Omegon Reticle eyepieces Illuminated crosshair eyepiece, 12.5mm

$ 89.00*
Filters > Nebulae filters (5)
Filters

Omegon Filters Nebula/ city light filter 1.25 ''

$ 39.90*
Filters > Other (1)
Filters

Omegon Filters Color filter set 1,25'' (6 pieces)

$ 69.00*
Astrophotography > Camera adaptor (6)
Camera adaptor

William Optics Camera adaptor Adapter M48 für Canon EOS Super high precision

$ 142.00*
Astrophotography > Camera mounts (4)

Omegon Easypic Universal Smartphone Adapter

$ 129.00*
Astrophotography > Other (4)

ProAstroGear Black-CAT-51 mount for ZWO ASIAIR, EAF and guidescope

$ 61.00*
Mountings & accessories (1)
Tube clamps

William Optics Tube clamps Cat Mounting Ring

$ 76.00*
Observatories (1)

Omegon Tent observatory

$ 189.00*
Media > Astro books (3)
Book

Dorling Kindersley Book Stargazing for Beginners

$ 27.90*
Media > Other (1)
Star chart

Omegon Star chart Planisphere

$ 14.90*
Outdoor (2)
Headlamp

Omegon LED headlamp

$ 13.90*
Maintenance & Cleaning > Lens cleaners (3)

Omegon 7-in-1 lens cleaning set

$ 19.90*
Maintenance & Cleaning > Other (2)

Omegon microfibre cleaning cloth 20cm x 20cm

$ 4.90*
Miscellaneous (1)

Star In A Star Moon Hat

$ 17.90*
Astronomy (2)
Filters

Omegon Filters Moon filter 1.25"

$ 19.90*
Globes & Maps (1)
Continent map

Oculum Verlag Sky Quality Map Europe

$ 18.90*
Solar Observation (2)

Baader Sun filter foil A4 210x297mm

$ 31.90*

*All prices include VAT plus shipping costs.

William Optics Apochromatic refractor AP 51/250 RedCat 51V2  OTA
Carrying case included.
William Optics Apochromatic refractor AP 51/250 RedCat 51V2  OTA
Focusing Mask
William Optics Apochromatic refractor AP 51/250 RedCat 51V2  OTA
Body
William Optics Apochromatic refractor AP 51/250 RedCat 51V2  OTA
Field rotator & tilting mechanism
William Optics Apochromatic refractor AP 51/250 RedCat 51V2  OTA
Original William Optics
William Optics Apochromatic refractor AP 51/250 RedCat 51V2  OTA
Example

Customer reviews

Excellent

Review by W. W. on 09.05.2022 18:06:17

( 5 / 5 )

Excellent delivery and service.
The scope is absolutely lovely. Quality case supplied with it. Very happy with my purchase.

Smått men meget godt

Review by J. K. on 06.09.2021 20:25:15

( 5 / 5 )

Det jeg vil kommentere her er den oppgraderte versjonen av William Optics Red Cat 51 som jeg ble eier av for rundt ett år siden ?og har vært veldig fascinert siden den gang og er det absolutt fortsatt. Dette lille teleskopet har ett objektiv på 51mm en brennvidde på 250mm og ett åpningsforhold på F= 4,9 ett rimelig raskt teleskop for astrofotografering men er også meget godt egnet for natur og dyreliv.




Høydepunktene i RedCat 51 APO (oppgradert versjon)
4 elementer Petzval flatfeltdesign med FPL-53 optikk
Rask brennvidde f/4,9
Full ramme dekning
Utskiftbart kamerafeste (Canon / Nikon / Sony / Pentax / M4 / 3 / Fujifilm)
Kompatibel med ethvert 48 mm (2 ") bildefilter
Super lys Bahtinov -maske + linsedeksel
Feltrotator
1,4 kg kun inkludert monteringsbase. En solid bæreveske for oppbevaring får man også med . Man kan også få kjøpt en vinkelprisme fra William optics spesial lagd for Redcat 51 hvis man skal observere visuelt med den noe jeg har prøvd og ble både overrasket og meget fornøyd. Det første jeg tenkte når jeg tittet igjennom ett 25mm kvalitets okular på Messier 45 Pleiadene var jøss så stort universet virker igjennom deg da for M 45 ble ganske liten men meget skarp og tydelig, samtidig med høy forstørrelse på månen ble kratere som Schiller meget imponerende tydelig og skarp avtegnet. Så trenger man ett lite reise teleskop eller et autoguider system til hoved teleskopet så har du alt du kan ønske deg i en Redcat51 fra William Optics.

Ole Jonny Kinn

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