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Lunt 100mm H-alpha Solar Telescope Feather-Touch Focuser and Pressure Tuner

Lunt 100mm H-alpha Solar Telescope Feather-Touch Focuser and Pressure Tuner
Our Price:  £6,478.00(Inc. 20% VAT)

Model:  L0551401
Brand:  Lunt
Telescope Type:  Solar Telescope

These H-alpha telescopes with 100 mm aperture and 800 mm focal length offer with an internal Etalon system a bandwidth of <0.7 Angstroms. Professional accessories such as Feather-Touch focuser from Starlight Instruments, sol searcher from TeleVue, and the new air-pressure tuning system “Pressure Tuner”, belongs to the standard equipment. Tube rings with dovetail plate and a robust transport case are included in the package. An instrument for the ambitious solar observer.

The LS100THa telescope is available alternatively with B1200, B1800 or B3400 blocking filter. We recommend the B1800 for imaging. The giant B3400 blocking filter in straight 2” extension tube is optimal for imaging with very big CCD imagers.

Also with these large telescopes the double stack method can be applied to reduce the bandwidth. Front mounting an additional available LS100FHa H-alpha filter (article no. L0550400) on a LS100THa telescope will provide <0.50 Angstrom bandwidth. And that with full 100 mm aperture!

Delivered in the Box

  • H-alpha Telescope with internal Etalon and 102mm Aperture
  • Pressure Tuner system
  • B1200 or B1800 or B3400 blocking filter in star-diagonal
  • Starlight Instruments 2" Feather Touch focuser
  • Tube Ring with dovetail plate
  • Sol-Searcher
  • Transport case

What is the „Pressure Tuner“ system?
The air pressure of the atmosphere varies, depending on if you are at sea level or on a mountain. Unfortunately also the sensitive Etalon filter systems respond to these air pressure variations. The wavelength range that is allowed through the filters, shifts as a function of the air pressure. This shifting is indeed minimal, but at bandwidths of less than one Angstrom it is already clearly visible. If the filter is not adjusted precisely to the H-alpha wavelength, the image of the sun through the telescope degrades, prominences and surface details are no longer visible.

Therefore, the Etalon filter systems have to be adjusted to the prevailing air pressure at the observation location. This “Tuning” called adjustment is typically done by a mechanical tilting of the filter. At sizes of a few Angstrom, it is obviously not easy to achieve the exact adjustment by mechanical tilting. And because the filter is no longer perfectly straight in the beam path, but slightly oblique, there may also be optical failures.

The new air-pressure system “Pressure Tuner” by Lunt Solar Systems takes a different path. The Etalon filter will not be tilted to only simulate a balance to the air pressure, but the air pressure in the filter system is in fact adapted by 100 percent to the real external air pressure. Thereafter the air surrounding the Etalon can simply be compressed or decompressed by the tuning system in order to change the air pressure between the surfaces. This allows the Etalon surfaces to always remain at the same perfect angle to the light waves but changes the diffractive index of the air in the chamber and thus accomplishes the same tuning expect that it goes around + or - 0.4 Angstrom on either side of the centerline. Therefore, the patent-pending “Pressure Tuner” system from Lunt Solar Systems is also called “True Doppler Tuning”, and it achieves much better results than conventional tuning systems.

Technical data:
  • Aperture: 102 mm
  • Focal length: 714 mm
  • Bandwidth: <0.7 Angstrom
  • Tuning: air-pressure tuning system
  • Blocking Filter: B1200 or B1800 or B3400 - with 1.25" and T2 connection 
  • Focuser: Starlight Instruments Feather Touch with 10:1 reduction
  • Weight: 6.6 kg
  • Length: 62 cm

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Internal Double Stack Module with Pressure Tuner for LS100THa Telescope

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Internal double stack filter with air-pressure tuning system. Reduces the bandwidth to <0.5 Angstrom!