William Optics RedCat 51 Flatfield APO Full Frame 51/250 mm f/4.9

The William travel apochromat RedCat 51 K.RC51lx Gen. 2 is perfectly suited for astrophotography and nature photography on photo tripods or travel mounts.

♦ Aperture 51 mm / focal length 250 mm / focal ratio f/4.9

♦ Petzval design with chromatic aberration free FPL53 objective (4 elements in 3 groups)

♦ Latest version - Gen2 - from William

♦ Very well corrected image field of 44 mm diameter - even suitable for full-frame cameras

♦ Camera connection via male M48 thread (suitable adapters are available) - working distance 55 mm

♦ 360° rotation of the camera for the right display window

♦ Camera Sensor Tilt Fine Adjuster

♦ Focusing via precise helical focuser

♦ Thread for mounted 2" filters (M48x0.75 thread, female) when used as camera lens

♦ Optional Amici prism for attaching eyepieces for visual use - the 2" filter threads can´t be used then

♦ Flexible dovetail bar at the base (long version), suitable for Vixen style saddle plates, Arca-Swiss style saddle plates, and with female 1/4" photo thread

♦ Nylon carry case and Bahtinov mask for astrophotography are included in the scope of delivery

♦ Tube length only 225 mm / weight only 1.5 kg - perfect for on the way

 

William Optics RedCat 51 Travel Apochromat for Astrophotography and Nature Photography

This apochromatic refractor is intended for all astrophotographers and nature photographers who are searching for a transportable and tack-sharp telephoto lens. Due to the 4-element Petzval design, a fully corrected image field of 44 mm diameter without chromatic aberration is achieved. Thus even the deployment of full-frame cameras is possible. However, with 225 mm length, the apo ist not larger than a normal telephoto lens. But it can do much more.
 

The application areas of the RedCat 51 apo:

♦ Astrophotography
With 250 mm focal length and fast f/4.9, short exposure times are possible. The working distance of 55 mm allows using all popular astro cameras and DSLR/SLR cameras. Due to the 2" filter thread which is integrated in the helical focuser, using nebula filters is also possible. Include in the scope of delivery is a Bahtinov mask. The mask helps when focusing and is integrated in the objective cap.

♦ Countryside photography and animal photography
The RedCat 51 is also perfect for, for example photographing animals. The slip-proof helical focuser allows focusing within seconds. The image quality will impress you.

♦ Observation with eyepieces
Of course you can also observe with the RedCat 51. With the optionalen star diagonal almost all popular 1.25" eyepieces can be attached. The angled view is helpful when observing objects close to the zenith as well as when observing nature at daytime, the design as Amici prism provides a correctly orientated image. You can find this item, as well as a matching eyepiece, in the accessories section.


 

Aperture:	51 mm
Focal length:	250 mm
Focal ratio:	f/4.9
Optical design:	4 elements Petzval design
Glass types:	FPL53 and FPL51
Illuminated and corrected image field:	44 mm diameter
Camera connection:	M48x0.75 thread (male)
Working distance from the M48x0.75 thread:	55 mm Backfokus
Additional thread:	M56x0.75
Filter thread:	2" filter thread in the adapter from M56 to M48
360° Rotation:	yes
Base plate:	suitable for Vixen style saddle plates, Arca-Swiss style tripod heads and photo tripods
Diameter of dew shield:	80 mm
Tube length:	225 mm
Tube weight:	1.5 kg

In the box:
♦ RedCat 51 travel apochromat
♦ M48 camera mount
♦ Patented Bahtinov mask
♦ Dovetail Vixen / Arca Swiss style
♦ Nylon carring case