Configuring an Off-axis Guider with the SpaceCat

September 7, 2022

Just wanted to document the spacing and backfocus distance for the ZWO ASI1600MM-Pro with the electronic filter wheel and OAG. The William Optics SpaceCat 51 allows a maximum distance of 57.9mm to achieve minimum focus, so I like to be somewhere close to 50mm when everything is totaled up--and looking good:

• ASI1600MM 6.5mm
• ZWO EFW 20mm
• M42-M48 ~5mm
• M48 spacer 5mm
• OAG 10.5mm
• 42-M48 ~3mm

Total: ~50mm