Baader Solar Filter SunDancer II TZ-3S H-alpha 2"/1.25" (71929)

The Baader Sundancer II transforms smaller refractors into solar telescopes for observing the Sun in the H-alpha line. It enables viewing of the Sun's chromosphere, including dark filaments, bright flares, and striking prominences on the solar surface.

The Sundancer is easily inserted between the diagonal mirror and the eyepiece or camera and connects to a power source. It automatically heats to the optimal operating temperature, requiring no manual adjustments even during extended observation sessions. Power can be supplied via the included power pack or an optional power tank.

Fine-tuning of the transmission line for different telescope systems is possible using the control box. The micrometer screw allows quick adjustments into the blue wing of the H-alpha line, compensating for Doppler effects during fast solar events.

Key Features:

• H-alpha Observations: Suitable for visual use, photography, and binocular setups.

• Integrated Telecentric Lens: Extends the telescope's focal length by a factor of three, achieving an ideal f/30 aperture ratio for H-alpha observation with f/10 telescopes.

• Wide Compatibility: Recommended for telescopes up to f/8 and usable down to about f/6.5 (with increased half-width on faster telescopes).

• Full Solar Disk Imaging: Visible in telescopes with focal lengths up to approximately 600mm.

• T2 Thread Compatibility: Enables attachment of larger cameras or bino-viewers without requiring a glass path corrector in most cases.

Durability and Handling:
The Sundancer II features a dielectric coating on its block filter (instead of silver) and an airtight oil-preserved SolarSpectrum Etalon filter, ensuring longevity if properly maintained. It must not be stored below 0°C to prevent damage caused by slushy oil filling. For use in colder conditions, thermal insulation is required.

Explanation of Components:

• Etalon Filter: Isolates the H-alpha wavelength through interference and is controlled by a temperature regulator.

• Telecentric Lens: Provides a parallel light beam necessary for proper Etalon function while extending focal length.

• Block Filter: Reflects excess sunlight before it reaches the Etalon to protect it from heat and blocks unwanted wavelengths transmitted by the Etalon.

Energy Protection Filters:
For refractors with apertures up to 80mm, no additional filters are required. Larger optics or telescopes with secondary mirrors (e.g., Newtonians, Maksutovs, SCTs) require an additional D-ERF (dielectric energy reflection filter) mounted at the front of the telescope to block unnecessary solar energy.

Specifications:

• Connection (to the telescope): 2"

• Connection (to eyepiece): 1.25"

• Connector (at camera end): T2

• Central wavelength (nm): 656

• Half-value width (Å): 0.6

• Operating temperature (°C): 0 to +40

• Recommended telescopes: Refractors with f/6.5 - f/8 aperture ratios

Included Equipment:

• Power pack for operation

• Transport case for safe storage

General Information:

• Type: Solar Filters

• Type of build: Line filter