Baader Universal Alan Gee II 2" Telecompressor for Observation and Photography

The Baader UAG II reduces the focal length of Schmidt Cassegrains for more field of view, it is ideal for binoviewers, but also for astrophotography.

♦ Connection telescope side: 2" barrel and T2 internal thread with the 7.5 mm T2 extension (included in delivery)

♦ Connection eyepiece side: T2 external thread

♦ Optimum working distance: 121 mm from the T2 external thread

♦ Reduction factor at 121 mm working distance: 0.59x

♦ Suitable for all Schmidt Cassegrain telescopes from 8" aperture - visually also suitable for EHD and ACF telescopes

♦ Optimized for binoviewers, the focal length of the SCT is shortened and the field sharpness is improved

♦ Can also be used with cameras with sensors up to APS-C format, the speed of the SCT is improved from f/10 to f/5.9

 

Baader Universal Alan Gee II - 2" Telecompressor

Roland Christen developed the Alan Gee as telecompressor and field corrector for Schmidt-Cassegrain telescopes. Now we offer the Alan Gee in a practical 2" housing as UAG II. This makes this exciting compressor even more flexible.

The long working distance is optimized for binoviewers. With the path of the binoviewer you achieve the optimal visual correction and expand the field of view by approx. 40%. You can also use the UAG II in front of a star diagonal mirror or prism.

The UAG II is supplied in a practical 2" housing. Thus it fits in every 2" receptacle. Using the T2 extension (7.5 mm) supplied, the UAG can also be connected to adapters or star diagonal prisms and mirrors with T2 external thread. The UAG can also be connected directly to the telescope via T2.
 

Connection eyepiece and camera side:

On the eyepiece side, the UAG II offers a T2 external thread. You can connect binoviewers or the photo adapter to this thread.
 

Use with binoviewer:

Connect the binoviewer directly to the T2 thread of the UAG and insert the UAG into the 2" star diagonal or screw the UAG to the T2 thread of the T2 prism or mirror. This configuration works with all SC, EHD or Meade ACF telescopes with 8" aperture or larger.
 

Visual use with eyepieces:

The UAG comes between the focuser and the star diagonal. The prerequisite is that the telescope is equipped with a 2" adaptation. A 2" focuser with SC connection is ideal.

For 2" star diagonals with the 2" female thread, you can unscrew the telescope barrel and replace it with a reduction to T2. Thus the UAG fits to the zenith mirror instead of the 2" receptacle. You save valuable optical path.
 

Photographic use:

The UAG II is suitable for DSLR, system cameras and astro cameras with sensors up to maximum APS-C format (approx. 28 mm diagonal). Full-frame format sensors would vignet too much at the edge. The working distance from the T2 thread on the camera side is 121 mm to the sensor. You will achieve an improvement in speed from f/10 to f/5.9 (or from f/11 to f/6.49). The curved field of Schmidt-Cassegrain telescopes is also flattened. The stars at the edge of the field become sharper.
 

Optical design:	Field flattener and tele compressor
Connection telescope side:	2" barrel and T2 (M42x0.75) internal thread
Connection eyepiece side - camera side:	T2 (M42x0.75) external thread
Working distance:	121 mm from the T2 thread