Baader's new RCC Off-Axis Guider (OAG) # 2956950 is matched specifically for the Baader RCC-I Coma Corrector and Digital SLR cameras. The guider's 36.5mm body length sets the backfocus at the 91.5mm nominal distance required for the RCC-I.
This OAG accepts 1.25" autoguiders and guiding eyepieces. The lower part of the body has a standard male T/T2 thread on one side (for camera attachment via a seaparate T ring) and a female T/T2 thread on the other (for attachment to the RCC Coma Corrector).
The RCC Off-Axis Guider incorporates convenient axial and radial guidestar adjustment, without loosening the main camera connection. For axial guidestar alignment, simply turn the small knurled thumbscrew in either direction to shift the guidestar along the optical axis. For radial (side to side) adjustment, loosen the bottom knurled thumbscrew and rotate the body radially (140 degree range). Simple, precise, and robust.
The off-axis prism is 9.35mm wide. The inside tube is 38mm in diameter. Depending on your adjustments, the prism will intrude into the light path by about 6-7mm leaving a clear aperture of 31-32mm.
The weight of the RCC Guider by itself is 165gm (5.8oz).
Until recently (mid-2012) Celestron sold an OAG that was made for them by Baader. It was similar to this item (but not the same as many people incorrectly assume). The guider attachment here is different and sized to give the correct back-focus distance when used with the RCC-I which the Celestron OAG will not do. Also, Baader uses the same 1.25" eyepiece holder in both products, with the result that this Baader branded OAG often has the "Celestron" label on the eyepiece holder.