5-element advanced Petzval with Super ED and lanthanum glass
Imaging
Image circle
60 mm
Camera format
Medium format / full frame / APS-C / Micro 4/3
Full-frame coverage
Yes
Back focus
No flattener required
Corrected field
Native medium-format flat field
Mechanical
Focuser
WIFD rack-and-pinion internal focuser
Weight
7.96 kg / 17.55 lb
Tube length
512.9-617.9 mm
Dovetail
Losmandy-style dovetail
Astrophotography Fit
Best for wide-to-mid-field nebulae and general deep-sky imaging when the mount, camera format, and correction hardware are chosen as one system.
William Optics UltraCat 108 sits in the telescope slot for wide-to-mid-field nebulae and general deep-sky imaging. The useful headline specs are aperture 108 mm, focal length 518 mm, f/4.8.
Camera coverage: Medium format / full frame / APS-C / Micro 4/3. Image circle: 60 mm. Back focus: No flattener required.
Fast astrographs collect signal quickly, but they are unforgiving: collimation, tilt, filter behavior, and back-focus spacing show up immediately in star shapes.
Weight matters here: 7.96 kg / 17.55 lb. Leave payload headroom for the camera, guider, focuser, dew control, and cables instead of judging the mount by bare tube weight alone.
Best paired with
Rigid focuser, tilt adjuster, and exact corrector spacing
Cooled cameras with a sensor inside the corrected image circle
High-throughput filters that behave well at fast focal ratios
Not recommended for
Users who do not want to tune collimation, tilt, and spacing
Thick or narrow filters that show strong bandpass shift at fast focal ratios
Loose camera adapters or focusers that cannot hold the imaging train square
Where To Buy
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