Advantages and disadvantages in using an off-axis guider
Auto-guiding with an Off-axis Guider has certain advantages as a separate guide scope is not required. This also reduces the weight the mount has to carry and eliminates possible flexure.
On the other hand, the range of suitable guiding stars will be reduced as the guide star will need to be within the field of view of the main scope which in turn will be relatively small. For example, when one compares the field of view of an 80mm F/5 refracting guide scope to an 8-inch F/10 SCT with an off-axis guider the 80mm refractor will have 5 times the field of view. However, you can overcome this by investing on a more sensitive guide camera. There is not really a better way but rather what better suits your circumstances.
Opticstar Off-Axis Guider connectivity.
A T-thread 10mm extension is supplied with the Kit. This serves a number of purposes and may be necessary to make the two cameras par-focal. It can be used to push the focal plane of the guide camera or imaging camera by 10mm away from the Off-axis Guider. Alternatively, it can be used to push a DSLR camera away from the Off-axis Guider because the camera’s flash-unit or handle may physically interfere with the Off-axis Guider or focuser knob of smaller aperture catadioptic telescopes including SCT and Maksutovs.
Off-Axis Guider specification
- 10mm optical path.
- Large free aperture (39 mm) on camera side, 45mm on telescope side.
- Off-axis camera guide-port can be focused independently (0-15mm range).
- 3-position, 120-degree rotatable design (imaging camera side).
- Range of optional adapters available.
Included adapters
- Telescope adapter 48mm(M) to 2" nosepiece, threaded for filters.
- 10mm Camera T-extension (M42 x0.75).
Carries full one year UK warranty.
