BAADER SunDancer II H-alpha solar filter
The Baader SunDancer II (with SolarSpectrum's heated H-alpha Etalon filter) transforms an existing telescope quickly and easily into a professional H-alpha solar telescope. For telescopes up to 80 mm aperture, no further accessories are needed: the SunDancer II already includes a 3x achromatic telecentric lens with T-2 connection; the entire SunDancer is simply plugged between the diagonal and eyepiece and connected to a power supply. It then automatically warms up to the optimum operating temperature. No readjustment is necessary even during long observing sessions. Adjusting the transmission line, e.g. to suit different optical systems is possible via the control box; the micrometer screw can be used to quickly shift the transmission line to the blue wing of the H-alpha line to compensate for the Doppler effect during fast H-alpha events on the sun.
An additional D-ERF energy protection filter in front of the telescope is required only on telescopes with an aperture of more than 80 mm; alternatively, the telescope can also be diaphragmed up to 80 mm with an optional diaphragm in front of the lens.
Power is supplied via the included power supply or via an optional PowerTank.
Solar disk and prominences
The H-alpha filter has a mean bandwidth of 0.6 +/- 0.1Å at telescopes with f / 10. The telecentric (corresponds to TZ3 # 1363070, soon available separately, but also with integrated 12 nm blocking filter) extends the telescope focal length by a factor of three, so that at f / 10 telescopes the focal ratio becomes f / 30 which is ideal for H-alpha solar observations. The SunDancer II is recommended for telescopes up to about f/8 and can be used well up to about f/6.5; on faster telescopes it increases the bandwidth causing less detail to be seen.
Visual, photographic and binocular head
The entire solar disk can be viewed in telescopes up to about 600 mm focal length. A T-2 thread under the eyepiece clamp also allows for the adaptation of larger cameras. The SunDancer II is also compatible with the SolarSpectrum Research Grade 0.4x 2 "(# BAD2459260) telecompressor, so that images of the entire sun can be captured even on an MFT sensor with telescopes up to 600 mm focal length.
Particularly attractive is the space-saving connection of a binocular head via the T-2 thread. In most cases, the use of a focal compensator is not necessary: the telecentric barlow provides a parallel light beam and at the same time shortens the necessary backfocus.
Long durability
The dielectric coating of the blocking filter (instead of the usual silver coating) and the hermetic storage of the SolarSpectrum Etalon filter in oil prevent the aging processes suffered by other simpler filter designs. With proper treatment, the SunDancer II will retain its performance for many years. Please note that the filter, like any H-alpha filter with Fabry-Pérot Etalon, must be protected from frost. It should not be stored below 0°C, otherwise the oil will become viscous increasing in volume and will separate the optical elements, damaging the filter. Thermal insulation is necessary for use at lower temperatures.
General characteristics:
- Quiet heated H-alpha filter with integrated 3x telecentric system with 2 nm blocking filter.
- Half-width (FWHM) of 0.6 ± 0.1 Å with an effective focal ratio of f / 30
- Aging resistant: the dielectric coating of the blocking filter and the hermetic storage of the SolarSpectrum Etalon filter in oil prevent the aging process
- The entire disk of the sun, as well as the bulges, are visible in a telescope with focal lengths up to about 600 mm.
- It shows bumps and details of the solar surface for visual observations, as well as for photographs and with binoviewers (binocular heads).
- For telescopes with an aperture of 80 mm or less, no additional D-ERF (energy rejection filter) is needed
- Easy-to-use electric temperature control; additional micrometer screw for observing rapid changes in the blue wing of the H-alpha line
- Revolver: 2", 1.25", 1.25
H-alpha BAADER SunDancer II solar filter
