Baader SunDancer II 4x Telecentric System TZ-4S
- Delivers a plane-parallel, achromatic beam of light with 36 mm diameter
- Designed especially for H-alpha and CaK subangstroem etalon filters
- Includes a ½" filter cell for the 2 nm block filter of the Baader SunDancer II H-alpha filter
- Can also be used in place of a Barlow lens, expands the telescope focal length by 4x
- BBAR (Broad-Band Anti-Reflection) coating
- Anti-reflective thread and blackened lens edges against reflections and for maximum contrast
- Image circle 36 mm, in a nominal in 97 mm from base of the T-2 thread
- 1¼" and 2" nosepiece with 1¼" filter thread, T-2 thread on camera side
- 12.5 mm (1/2") filter exchange tool included
- 5-year warranty if handled properly
Important note: We deliver the SunDancer II H-alpha only with TZ-3S. An alternative cover with TZ-4S is unfortunately not possible.
Telecentric systems are mainly used in H-alpha filters for solar observation, where the 1/100 lambda plane-parallel etalon in the H-alpha filter requires a perfectly parallel beam of light over the entire image. These telecentric systems deliver very sharp images, but are usually only optimised for the H-alpha wavelength.
This achromatic SunDancer 4x telecentric is designed for the entire visible spectrum and can therefore not only be used on H-alpha systems, but the TZ-4S, as well as the Baader SunDancer II Telecentric System TZ-3S can also be used instead of a Barlow lens. Due to the parallel beam of light, it is very good-natured with regard to 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 image quality of the TZ-4 do not change, even if the camera or eyepiece is mounted well behind the nominal working distance (97 mm from the base of the T-2-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 T-2-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 connection on the telescope side is made via a dual 1.25"/2" nosepiece with safety kerfs (these prevent tilting due to an incorrectly positioned safety groove and at the same time provide a secure hold). On the camera side, the T-2 thread provides a tilt-proof, fixed connection even to heavy cameras or to T-2 eyepiece clamps. For the T-2 thread, adapter 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 T-2 thread of the SunDancer II H-alpha filter (instead of 65 mm with the original TZ-3S).
To use the TZ-4S with the SunDancer II H-alpha filter (left), the shiny block filter must be removed from the TZ-3S (with red label) and inserted into the TZ-4S.
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)
The SunDancer II Telecentrics
- Baader SunDancer II Telecentric System TZ-3S (#1363070) with gold anodized label: Achromatic 3x telecentric with 95 mm working distance from the base of the T-2 thread and 27.5mm clear aperture. Provides the desired focal ratio of f/30 on telescopes with f/10. This telecentric is also available without the SunDancer II H-alpha filter, but then only without the 2 nm block filter of the H-alpha filter. For clear identification, this telecentric has a gold-colored anodized banderole.
- TZ-3S with 2nm block filter and red anodized label: Achromatic 3x telecentric of the Baader SunDancer II H-alpha Filter (#1363056) is equivalent to the Baader SunDancer II 3x Telecentric TZ-3S, but additionally contains a 2nm (FWHM) block filter. It shimmers golden when you look into the SunDancer from the telescope side. This block filter is mandatory to protect the actual H-alpha filter from solar radiation. For clear identification, this telecentric has a red anodized band, otherwise identical to the Baader SunDancer II Telecentric System TZ-3S (#1363070) . Please note: We deliver the SunDancer II only with TZ-3S. An alternative cover with TZ-4S is unfortunately not possible.
- Baader SunDancer II Telecentric System TZ-4S (#1363080 ) with violet anodized label: Achromatic 4x telecentric with 97 mm working distance from the base of the T-2 thread and 36mm clear aperture. Provides the desired focal ratio of f/30 on telescopes with f/7.5. For clear identification, this telecentric has a violet anodized label. This telecentric does not include the 2 nm blocking filter of the H-alpha filter; for use with the SunDancer II, the 2 nm block filter must be converted from the TZ-3S of the SunDancer II filter to the TZ-4S. The use with large SolarSpectrum H-alpha filters with already integrated block filter and additional energy protection filter is possible without this additional 2 nm block filter.
The blocking filter reflects the sunlight just before the etalon and the telecentric system. This protects the etalon from excessive heat. In addition, an etalon also transmits wavelengths that are a multiple of the desired transmission line; these are also stopped by the blocking filter, too. The blocking filter or the TZ-3S with pre-installed blocking filter are not available separately.
The 3x-Telecentric TZ-3S without block filter, recognizable by the gold-colored ring
The 3x-Telecentric with integrated block filter is only available together with the SunDancer II H-alpha filter. Here the block filter of the SunDancer II is pre-installed, the version is recognizable by the red ring.
The 4x-Telecentric TZ-4S
without block filter, recognizable by the
violet ring
