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Baader SunDancer II H-alpha Filter

Original price $3,197.00 - Original price $3,197.00
Original price
$3,197.00 - $3,197.00
Current price $3,197.00
SKU SNDNCR (Baader #1363056)

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  • Silently heated H-alpha-Filter includes a compact new 3x telecentric system with 2nm hard-coated blocking filter
  • Half-width (FWHM) of 0.6±0.1Å at an effective focal ratio of f/30
  • Resistant to aging: The dielectric coating of the blocking filter and the airtight storage of the SolarSpectrum Etalon filter in oil prevent the aging process
  • The complete disk of the sun as well as prominences are visible in telescope with focal lengths up to about 600mm shows prominences and solar surface details for visual observations as well as for photography and bino-viewers
  • For telescopes with 80mm aperture or less, no additional D-ERF (energy rejection filter) is necessary
  • User friendly electrical temperature control; additional micrometer screw for observing fast changes in the blue wing of the H-alpha-line
  • Dual Nosepiece: 2", 1,25"

H-alpha observing made easy

The Baader SunDancer II (with its heated H-alpha Etalon from SolarSpectrum) transforms an existing telescope quickly and easily into a professional H-alpha telescope! For telescopes up to 80mm aperture, you do not need any further accessories: The SunDancer II already includes a compact achromatic (!) 3x telecentric which connects to the Etalon with T2 threads; the entire SunDancer is simply plugged between star diagonal and eyepiece and connected to a power source. It then automatically heats up to the optimum operating temperature. No readjustment is necessary even during long observation sessions. Finetuning the transmission line e.g. to adapt to different telescope systems is possible via the control box; the micrometer screw can be used to quickly shift the transmission line into the blue wing of the H-alpha line to compensate for the Doppler effect during fast H-alpha events on the sun

Baader SunDancer II on Triband-SCT Multi-Purpose Telescope

An additional D-ERF energy protection filter in front of the telescope is necessary only on telescopes with more than 80mm aperture; alternatively, the telescope can also be stopped down to 80mm with an optional diaphragm in front of the lens.

Power is supplied either via the included power supply or via an optional PowerTank. A detailed description of the possible applications and the requirements for the telescope can be found in the operating instructions under the "Downloads" tab.

Solar disk and prominences

The H-alpha filter has a half width of 0.6 +/- 0.1Å on telescopes with f/10. The telecentric (which is also available separately as the TZ-3S #1363070, but without an integrated 12nm block filter) extends the focal length of the telescope by a factor of three, so that on telescopes with f/10 the ideal focal ratio of f/30 for H-alpha is achieved. The SunDancer II is recommended for telescopes up to about f/8 and is well usable up to about f/6.5; on faster telescopes the half-width increases. The half-width was chosen in such a way that both prominences and the solar surface are nicely displayed at the same time.

Visual, photographic and binocular

The complete solar disk can be seen in telescopes up to about 600mm focal length. A T-2 thread under the eyepiece clamp also allows the adaptation of larger cameras using any of the wide range of Baader T-2 accessories. The SunDancer II is also compatible with the SolarSpectrum Research Grade 0.4x Telecompressor 2" , so that the entire sun can then be imaged even on an MFT sensor with telescopes of up to 600mm focal length.

Particularly appealing is the space-saving connection of a bino-viewer via the T-2 thread. In most cases, a glass path corrector is not necessary: the telecentric provides a parallel beam of light and at the same time shortens the necessary back focus.


The dielectric coating of the block filter (instead of the usual silver coating) and airtight storage of the SolarSpectrum Etalon filter in oil prevent the aging processes of simpler filter designs. With proper treatment, the SunDancer II will retain its performance for many years. Please note that the filter - just like any H-alpha filter with Fabry-Pérot Etalon - must be protected from frost. It must not be stored below 0°C, as otherwise the oil will become thick and push the optical elements apart, damaging the filter. Thermal insulation is necessary for use at lower temperatures.

SKU (#) 1363056
USAGE Visual solar observation and solar photography
HBW (HALFBANDWIDTH) 0.6 +/- 0.1 Angstrom
OPTIONAL ACCESSORIES Additional D-ERF only necessary with telescopes over 80mm
INCLUDED ACCESSORIES SunDancer II H-alpha filter, control box for temperature control, 12V power supply, sturdy hard case, Baader Utility Bag, detailed manual



Baader SunDancer II H-alpha Filter – Manual and Applications Tipps

Baader SunDancer II - Quickstart

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