An off-axis guider (OAG) is particularly useful for my imaging setup since my telescope is an 8 inch Celestron SCT. SCTs focus by moving the main mirror, thus, susceptible to mirror shift as it tracks the sky. Since OAGs receive light directly from the main mirror, it can account for any mirror shift.
AOG setup by Askar for my 8 inch SCT, with ASI 174MM as guide camera and ASI 533MC as the imaging camera
I tried to minimize the components by removing the supplied helical focuser (focusing is done by sliding the guide camera instead). The OAG is placed before the filter drawer. Here’s a sample photo of M51 Galaxy imaged with a setup using the OAG at 1140 mm, f/5.7 (with a DIY reducer). To view other photos taken with this OAG, click here.
Related link: DIY Off-Axis Guider
Night Sky in Focus © Anthony Urbano | Bacoor, Philippines
Night Sky in Focus 