William Optics v2 RedCat 51 APO f/4.9
William Optics v2 RedCat 51 APO f/4.9William Optics v2 RedCat 51 APO f/4.9William Optics v2 RedCat 51 APO f/4.9
William Optics v2 RedCat 51 APO f/4.9William Optics v2 RedCat 51 APO f/4.9William Optics v2 RedCat 51 APO f/4.9

William Optics v2 RedCat 51 APO f/4.9

  (16 Reviews)
✓ 2 year warranty


10x in stock shipped 1-2 working days

About this product

Model:  wo_redcat_51lx
Part Number:  L-RC51II

NEW updated RedCat v2 51 / 250mm f/4.9 Apo

The latest v2 version of the popular RedCat 51 has an improved helical focuser and updated tension adjustment.

The William Optics RedCat 51 APO is a 51mm f/4.9 Petzval refractor that features synthetic fluoride (FPL53 and FPL51) glass elements for a full frame, flat field image.

Provides high resolution images when used for astrophotography or wildlife photography.

It's fast f/4.9 focal ratio and compact size makes it ideal for convenient wide field astrophotography or piggybacking. 

Incorporates a smooth helical focuser, a field rotator graduated by degree, a slot for 48mm filters and a reversible dovetail for either Vixen style* or Arca-Swiss mounting. 

Sky and Telescope Review of Redcat 51

Telescope Field of View Simulator


What's in the box

  • RedCat 51 f/4.9 scope
  • Soft Carry Case
  • Patented Bahtinov Mask


Focal RatioF/4.9
Focal Length250 mm
Objective TypePetzval (4 elements in 3 groups) and Ohara FPL 53 ED element. 
Image CircleΦ 44mm (Full Frame)
Dimensions225mm x 80mm x 80mm
Tube Weight1.47kg

Customer reviews

Average Rating (16 Reviews):  
Write a Review and share your opinions!

Rating (max 5):  
Very happy with scope
Monday, 16 May 2022  | 

The scope looks great, and the build quality is good. So far I haven't been able to test it as the clouds just won't go away. Taking some general test shots, the images look fine and focus is smooth and easy. Can't wait to use it in anger. Service from FLO was top notch as usual!!!

Rating (max 5):  
Awesome Piece of Kit
Sunday, 30 January 2022  | 

Absolutely excellent piece of kit. Build quality is fantastic and the built in bahtinov mask is amazing, very quick and easy to achieve perfect focus.
Literally the biggest complaint I can find is fine threads made of aluminium on the lens cap/bahtinov mask make squeaky sounds.
Granted, I'm using it on a crop sensor Canon but absolutely no vignetting to speak of and sharp, crisp stars across the whole field.
The usual stellar service from FLO is also nice, 15-20 working days delivery quoted at order, so naturally it was delivered in 14 working days

Rating (max 5):  
Totally newbie thrilled with red cat
Wednesday, 5 January 2022  | 

Iím really new to astrophotography and not had much luck so far mostly due to clouds and focusing. With a clear night last night I set this beautiful scope up and had a go not expecting much but omg it was fabulous and I got lots of photos of Orion Nebula that I only hoped to get and the detail was much more than I ever expected. Canít wait to get out tonight to try another target

Rating (max 5):  
A little star.
Friday, 3 December 2021  | 

There is a serious reason why this tiny scope is so popular amongst astrophotographers.
It's truly a gem. Optically excellent, build quality is also excellent. If you're on the market for small astrograph - well you've found one

Rating (max 5):  
Delighted with my RedCat.
Wednesday, 12 May 2021  | 

I could not be more pleased with my RedCat purchase. This is an outstanding little scope which I have used alongside my Samyang 135mm for wide field imaging of larger nebula targets. I can find nothing to fault with the RedCat. The finish is superb and the optical performance with my ASI1600 meets all my expectations. I am delighted I don't need to purchase a dedicated reducer/flattener and that my parafocal filters are really parafocal after all - not the case when used with my Samyang. As noted by others I cannot see me ever selling the RedCat - it is definitely a keeper. As ever the service from FLO was second to none.

Rating (max 5):  
Short and Sweet
Friday, 12 February 2021  | 

Everyone should own a Redcat! Its perfect for beginners like me to learn the night sky and to learn tracking and precision. I would recommend this as a first scope! I would also never depart with my Redcat even when I want something that goes a bit deeper (and I do) I wouldn't sell it or swap it! I hope I keep it pristine and clean and I have a feeling it will be with me for years to come as the build quality is second to none! its a dream in every area if you are in doubt get it now as soon as you can no idea how long WO will keep distributing them!

Rating (max 5):  
Roaring Redcat
Saturday, 6 February 2021  | 

Bought this to allow me to image some larger DSOs, and to get a feel for the difference apochromatic glass makes (other scops are Skywatcher Evostars (150 and 102)). First up the service from FLO was perfect - Redcats were in stock and the parcel was in my house within 48 hours. Well packaged up, and in its own padded soft case. This is a beautifully engineered piece of kit, and does not disappoint. Have used with Nikon DSLR (with extra WO adapter) and Altair Hypercam 269C. Image data of nebulae and larger galaxies are at a different league to what I was getting previously with the achromatic scopes. Also a really nice and forgiving focal length for the astrophotography beginner to use while they develop their tracking alignment skills. Super-portable, and I plan a few trips hiking up to higher dark skies to see what else it can do when the skies clear up........

Rating (max 5):  
Sevice review only...for now
Wednesday, 23 December 2020  | 

So late afternoon Friday 18th December I noticed the Redcat was in stock, 3 of them. I finally took the plunge and placed the order, who knows what next month brings. Monday 21st the package was dispatched, the country in chaos, not to mention Christmas just another three shopping days away. Wednesday 23 December, lunchtime in Southern France the DHL van arrives with the Redcat. That is amazing service...to FLO and DHL.. .'chapeau'.

Rating (max 5):  
Thursday, 19 November 2020  | 

I have been using the RC51 for about 2 months and I have only good things to say.

The build quality is exceptional and the performance is superb. The helical focuser offers great precision and once locked, it can stay focused during several sessions.

The package includes a very nice soft case and a handwritten inspection checklist certificate from William Optics. The scope screams high quality and even if it is a bit pricey when compared to others at the same focal length, it will certainly return your investment with the photos it will give you.

Rating (max 5):  
William Optics v1.5 RedCat 51 APO f/4.9
Sunday, 25 October 2020  | 

We bought the William Optics RedCat v1.5 as part of a portable rig that included the iOptron SkyGuider Pro, the ZWO ASIair Pro, iOptron Ball Head, iOptron tripod and the ZWO mini Finder guider and ASI120mm - mini bundle and ZWO ASIair Pro. We ordered all at the same time but were aware that some had a longer lead time than others. Throughout FLO were brilliant at keeping us informed and shipped some items earlier than agreed because we were still waiting for the tripod. Previously we have only used a GoTo Celestron 8SE so getting used to the small rig has required some effort but there are some great YouTube videos out there to help and we now we feel we can write a review of the components.

This is a great telescope and it is excellent for a portable rig, it focusses easily using the internal Bahtinov mask and delivers really good imaging capability for its size. I am sure it will be a companion to our exploration of the night sky for years to come.

Read all 16 customer reviews...


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