Baader SunDancer II Telecentric System TZ-4S

Baader SunDancer II 4x Telecentric TZ-4S

Telecentric systems are mainly used with H-alpha filters for solar observation, where the etalon in the H-alpha filter, which is plane-parallel to 1/100 lambda, requires a perfectly parallelized beam path over the entire image. These telecentrics provide very sharp images, but are mostly optimized for the H-alpha wavelength only.

This achromatic SunDancer 4x telecentric is calculated for the entire visible spectrum and can therefore not only be used on H-alpha systems, but also replace a Barlow lens. Due to the parallel beam path it is very good-natured regarding the working distance: While the magnification factor of a Barlow lens changes with the distance to eyepiece or camera (zoom eyepieces are also based on this principle), the magnification factor and imaging quality of the TZ-4S do not change, even if the camera or eyepiece is mounted well behind the nominal working distance (97 mm from the base of the T2-thread).

The achromatic SunDancer II TZ-4S illuminates an image circle of 36 mm at a distance of 97 mm from the base of ther T2-thread. The contrast is better than with the common methods used for higher magnifications: simple barlow lenses or eyepiece projection. With the 4x telecentric system, high magnifications for observing the solar system can be achieved even with long focal length orthoscopic eyepieces. The eye relief of the eyepieces used does not change, too! The focus position changes only 3 mm outward when using the 2" nosepiece of the telecentric, compared to a 2" eyepiece.

The telescope-side connection is made via a dual 1.25"/2" Barrel with Safety Kerfs (these prevent tilting due to an incorrectly seated safety groove and at the same time provide a secure hold). On the camera side, the T2 thread provides a tilt-proof, tight connection even to heavy cameras or to T2 eyepiece clamps. For the T2 thread, extension rings are available for almost all common connection systems (e.g. M48/2"/M68).

The TZ-4S in use with H-alpha-Filters

The TZ-4S was specially designed for the Baader SunDancer II H-alpha Filter and replaces the original 3x telecentric. This allows to use the SunDancer II H-alpha filter also on telescopes with f/7-f/8 with the optimal focal ratio of about f/30. Please note: For this, the 12 mm 2 nm H-alpha blocking filter, which is pre-installed in the front of the TZ-3S, must be installed in the TZ-4S. This blocking filter is not available separately. The ideal working distance when using the SunDancer II is then 70 mm from the base of the T2 thread of the SunDancer II H-alpha filter (instead of 65 mm with the original TZ-3S).

For H-alpha filters with up to 36 mm diameter with their own block and energy protection filter (e.g. SolarSpectrum filter), the TZ-4S can be used instead of the long-building Telecentric System TZ-4 (4x focal length) (BA2459256).