LS60THaDS50 Double Stack Telescopes
These telescopes with their 60 mm aperture and 500 mm focal length provide a very detailed resolution for observing and imaging the sun. However, with a weight of approximately 3 kg the telescopes can easily be carried by most photo tripods. The tube rings of these telescopes are fitted with a 1/4”-20 thread for mounting it on such tripods. The sensitive Etalon systems are well protected in the telescope tube installed and provide a bandwidth of <0.75 Angstrom. A integrated matched collimation lens set fully corrects on axis coma, astigmatism, and de-centering aberrations and provide a full spherically corrected flat-field solar telescope.
We offer these telescopes alternatively with our B600 or B1200 blocking filter to you. The larger B1200 blocking filter will be better for imaging, because it provides a smaller vignetting.
Normally these telescopes are equipped with a 2” Crayford focuser with 10:1 reduction. They are also available with the legendary Starlight Instruments Feather-Touch focuser, one of the best focuser in the world. Certainly also with 10:1 reduction.
All versions come with a robust aluminum-case as part of the standard package.
Delivered in the Box:
- H-alpha Telescope with internal Etalon and 60mm Aperture
- Internal Etalon with Pressure Tuner system
- External 50mm Double-Stack Etalon LS50FHa
- B600 or B1200 blocking filter in star-diagonal
- 2" Crayford focuser or Starlight Instruments 2" Feather Touch focuser
- Tube Ring with 1/4"-20 connection
- 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.