William Optics UltraCat 108 WIFD — 108 mm Petzval astrograph The 5-element optical system provides a 518 mm focal length at f/4.8, with a 60 mm image circle. Its Petzval design does not require an external field flattener.
Manufacturer model: William Optics UltraCat 108 WIFD · Specifications checked against manufacturer data on 2026-11-03
William Optics UltraCat 108 WIFD — 108 mm Petzval astrograph
The 5-element optical system provides a 518 mm focal length at f/4.8, with a 60 mm image circle. Its Petzval design does not require an external field flattener.
Focus and camera alignment
The WIFD rack-and-pinion focuser provides 30 mm travel and 1:10 fine adjustment. A camera rotator controls framing, while the Sensor Tilt Xterminator allows sensor alignment. The lens cover incorporates a Bahtinov focusing mask.
Imaging connections
STX tilt adjuster / rotator; M79 to M68, M54 and M48 adapters. Petzval focus depends on the complete camera train remaining within the telescope's focusing range.
Size and mounting
The tube length is 512.9–617.9 mm. OTA weight is 7.96 kg and the manufacturer lists 9.58 kg total weight. The current William Optics product specification lists a Losmandy-style mounting plate.
William Optics specifies two Super ED elements, one ED element, one lanthanum element and one X-element in the five-element optical system. The internal focuser moves the focusing mechanism within the telescope, while the rear tilt and rotation adjustments support sensor alignment and framing.
Compatibility notes
Petzval focus range must accommodate the complete imaging train; do not interpret recommended camera spacing as an exact flattener backfocus. Confirm supplied adapters and revision.
86137
Scheda tecnica
Apertura (mm)
108
Adattatori per camera
STX tilt adjuster / rotator; M79 to M68, M54 and M48 adapters
Formato camera
Medium format, full frame, APS-C and Micro Four Thirds
Rotazione camera
Camera angle rotator
Messa a fuoco elettronica
ZWO EAF compatible; use the manufacturer installation guide for the selected EAF model.
Richiede spianatore di campo esterno
No
Rapporto della messa a fuoco fine
1:10
Focale (mm)
518
Rapporto focale
4.8
Focheggiatore
WIFD rack-and-pinion
Corsa del focheggiatore (mm)
30
Maschera di messa a fuoco
Bahtinov mask incorporated in lens cover
Cerchio d'immagine (mm)
60
Elementi ottici
2 Super ED, 1 ED, 1 lanthanum and 1 X-element (5 elements total)
William Optics UltraCat 108 WIFD — 108 mm Petzval astrograph The 5-element optical system provides a 518 mm focal length at f/4.8, with a 60 mm image circle. Its Petzval design does not require an external field flattener.
Manufacturer model: William Optics UltraCat 108 WIFD · Specifications checked against manufacturer data on 2026-11-03
