Triband-SCT 9¼" – Multi-Purpose Solar Telescope on SC-Base

It is a common misconception that small telescopes are sufficient for observing the Sun as high magnifications can rarely be used at daytime. The nice little H-alpha and CaK telescopes which are quite common nowadays are great for a quick look at the Sun and to see the complete solar disk – but if you want to see fine details, you need  aperture and focal length to make use of those moments when the seeing is perfect.

The groundbreaking Baader Triband-SCTs have got an Energy Rejection Filter (ERF) – which is necessary for the SolarSpectrum CaK and H-alpha filters – already integrated into the Schmidt corrector plate. You don't have to pay the additional costs for an Energy Rejection Filter (ERF), which would be "astronomical" for telescopes between 8 and 11 inches. With its Triband-coating, the telescope is still perfectly fitted for narrowband Deep-Sky-photography, although it was made for solar observing!

  Triband-coating is an Energy Rejection Filter for observing the Sun, which does not interfere with narrowband Deep-Sky observations. Heat shields avoid heating of the telescope.

SolarSpectrum-Filter for H-alpha or CaK can be connected directly

The Triband-SC were developed for the SolarSpectrum H-alpha filters. The Energy Rejection Filter which is integrated into the Schmidt corrector plate eliminates the need for an additional D-ERF. The SolarSpectrum filters require the TZ-3 Telecentric System 2" – Research Grade (3x focal length) (#2459257 , € 445,- ) , to perform at its best at f/30; with the Telecompressor 2" H-alpha 0.4x – Research Grade, for Solar Spectrum (#2459260 , € 366,- ) with 16mm corrected field of view, you almost regain the original focal length of the telescope and can work both visually and photographically at lower magnifications.

In addition to the transmission window between 630 and 680 nm for H-alpha observation, the Energy Rejection Filter has a second window between 380 and 400 nm, in the dark blue/UV. It is made for using SolarSpectrum CaK filters without an additional Energy Rejection Filter.

In addition, the filter can be used, but only behind another filter such as a Cool-Ceramic Safety Herschel Prism 2" Mark II – Photographic (#2956510P , € 645,- ) or AstroSolar photo film ND 3.8 (also available as BDSF: OD 3.8 Baader Digital Solar Filter 200mm (#2459376 , € 157.91 ) in matching mount).

Solar observation in white light can be done with a Cool-Ceramic Safety Herschel Prism 2" Mark II – Photographic (#2956510P , € 645,- ) or a temperature-compensating ASTF front filter made of astrosolar film.

Depending on each model these are:

• 8" SCT = ASTF 200 – AstroSolar Telescope Filter OD 5.0 (#2459316 , € 176,- )
• 9.25" SCT = ASTF 240 – AstroSolar Telescope Filter OD 5.0 (#2459317 , € 201,- )
• 11" SCT = ASTF 280 – AstroSolar Telescope Filter OD 5.0 (#2459318 , € 215,- )

The Sun appears slightly light green. For increased contrast, we recommend a red filter like H-alpha 2" Bandpass filter (20nm) (#2961853 , € 165,- ) to reduce the influence of seeing, or the O-III 2" Super-G Filter (9nm) - CMOS optimiert (#2961551 , € 165,- ) .

A note about solar observing
Please note that a Triband SCT is no grab-and-go-telescope: Smaller telescope with less magnification will show nice images even at poorer seeing conditions, but a high-end telescope which pushes everything to its limits also requires a proper location. Make sure that your surroundings don't cause bad local seeing – only then you can take the telescope to its limits!

Use a Herschel Wedge or an ASTF front filter to see the sun in white light with large apertures and high resolution.

The Triband-SCTs are based on Celestron's Schmidt-Cassegrains, a well-tried and reliable no-frills telescope system. That's why they are also compatible with a multitude of accessories which were developed for regular Schmidt-Cassegrains – starting with filter drawers like the UFC or focusers like the Baader Diamond SteelTrack with optional motor focuser or the Celestron Fokussiermotor #821160 up to reducers. In contrast to 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 harmonize very well with UHC-L, O-III and H-Beta filters - that is all filters used for visual observations. At night, you only need to replace the H-alpha filter or Herschel wedge by a normal prism and eyepieces. Narrow-band 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.