Baader Triband SCT 11" for high-resolution solar observation

Baader Triband SCT - Versatile telescopes for professional applications

Based on the proven Schmidt-Cassegrain (SC) telescopes, the Triband SCs were developed with a Triband ERF-coated Schmidt plate. They are the ideal basis for detailed H-alpha solar observation with a large aperture. The telescopes are also suitable for deep sky observation.

With a large aperture for observing the sun
It is a widespread myth that small telescopes are sufficient for solar observation because high magnifications are not possible during the day.

The now widely available, nice little H-alpha and CaK telescopes are good for a quick look at the sun and to see it in its entirety; but to resolve fine details, you need aperture and focal length for those moments when the seeing offers perfect conditions.

Baader Triband SCTs have the energy protection filter required for CaK and H-alpha filters from Baader Planetarium and SolarSpectrum already integrated into the Schmidt plate. This eliminates the cost of an energy-saving filter, which would be truly "astronomical" for apertures between 8 and 11 inches. Thanks to the Triband coating, the telescope remains fully usable for narrow-band photography despite being designed for solar observation!

The special triband ERF Schmidt plate of the triband SCT has the following transmission ranges: 380 to 400 nm, 480 to 515 nm, and 630 to 680 nm.
In addition, it is blocked in the UV range (below 380 nm) and in the IR range (above 680 nm) to prevent both short-wave radiation and heat build-up.

The Triband Schmidt plate is blocked in particular in the IR up to 1450 nm, thereby preventing the tube from heating up. This eliminates the need for an additional large and precisely polished energy protection filter, and the optical precision of the Schmidt plate is fully retained.

Additional, rear-ventilated heat shields at the front of the tube and in front of the secondary mirror effectively reduce the absorption of radiant heat by the tube. This allows you to use the full resolution possible at your observation site. With videography, this enables extremely high-resolution detailed images of the sun. But in three passbands, not just in H-alpha. You can observe the sun in H-alpha or CaK light with a SolarSpectrum filter, as well as in continuum with a Herschel wedge or an ASTF filter.

The new system is also impressive visually in moments of good seeing, you will see the sun more breathtakingly than ever before.

TriBand pre-filter for narrowband observations
A tri-band SCT consists of a Schmidt-Cassegrain optical system with a tube and tri-band ERF-coated Schmidt plate, as well as rear-ventilated heat shields for the tube edge and secondary mirror (with neodymium magnetic mounts). The transmission windows are designed for calcium K, continuum (including H-beta and [O III]), H-alpha, [S II], similar to a UHC filter, and allow the use of additional narrowband filters.

Depending on the application, you may need additional accessories:

H-alpha: Solar Spectrum H-alpha filter, TZ-3 telecentric and TK0.4 or TK0.7 telecompressor. A D-ERF filter is not required.

CaK: Solar Spectrum CaK filter, K-line filter plus pre-filter for solar observation in calcium light

Continuum: Safety Cool-Ceramic Herschel wedge and, if necessary, suitable narrowband filters.

Deep sky (not for solar observation!): Deep sky filters depending on the type of application (RGB / H-beta / [O III] / H-alpha / [S II])

H-alpha observations
The Triband SCs were developed for SolarSpectrum H-alpha filters. The energy protection filter integrated into the Schmidt plate eliminates the need for an additional D-ERF. The SolarSpectrum filters require a telecentric system for triple the focal length to deliver the best performance at f/30; with a suitable telecompressor, you can return to the original focal length of the telescope and work with lower magnifications for both visual and photographic purposes.

Solar observation in calcium light
In addition to the transmission window between 630 and 680 nm for H-alpha observation, the energy protection filter has a second window between 380 and 400 nm, in dark blue/UV. This allows SolarSpectrum CaK filters to be used without an additional energy protection filter.
The Baader Calcium GEN-II 1.25" can also be used, but only in conjunction with another pre-filter such as a Herschel prism or ND 3.8 filter foil.

Solar observation in continuum (white light)
Solar observation in white light is possible with a Herschel prism or a temperature-compensating front filter made of Astrosolar foil.

Note on solar observation
Please note that a device in the performance class of a Triband SCT is not a grab-and-go telescope: Smaller telescopes with less magnification also show nice images even in poor seeing conditions, but a high-end telescope that pushes the limits of what is technically possible also requires a suitable observation site. Make sure that the environment does not cause air turbulence, only then can you fully use the potential of the telescope!

Deep sky narrowband observation & narrowband photography
These are based on the popular Celestron Schmidt-Cassegrains, a system that has proven itself in the night sky for decades. This means they are also compatible with all accessories for Schmidt-Cassegrains, from filter drawers such as the UFC to focusers such as the Baader Diamond SteelTrack with optional motor focuser or the Celestron focus motor, right through to reducers.

Unlike pure H-alpha telescopes, the Triband SCT can also be used at night: the filter coating allows CaK, H-beta, [O III], H-alpha, and [S II] to pass through. The telescopes therefore work very well with UHC-L, O-III, and H-beta filters, in other words, all filters used for visual observation. At night, you only need to replace the H-alpha filter or Herschel wedge with a normal prism and eyepieces. Narrowband photography is also possible; however, the Celestron EdgeHD and RASA telescopes with their reducers/field flatteners designed for modern cameras are better suited for deep sky photography.

11" TriBand SCT
Heat shield

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