The Lunt LS100MT with B1800 blocking filter is a powerhouse for serious solar observers and imagers. This fully modular hydrogen-alpha telescope combines the superior color correction of a 100mm FPL-53 ED triplet with the high-contrast performance Lunt Solar Systems is known for. Whether you're observing the Sun or switching to nighttime use, the LS100MT is built to deliver detailed views in every configuration.
This version of the telescope includes the B1800 blocking filter housed in a 2" diagonal, which increases the clear aperture to 18mm at the focal plane. For users pushing into higher magnifications, using wide-angle eyepieces, or imaging with larger sensors (APS-C or similar), the B1800 provides the wider, fully illuminated field necessary for crisp, edge-to-edge performance.
Why Choose the B1800 Blocking Filter?
The number in the blocking filter’s name refers to the size of the internal filter window in millimeters. For the 714mm focal length of the LS100MT, the 18mm aperture of the B1800 offers a wider unvignetted field than the smaller B1200. This makes it the preferred choice for those using binoviewers, large-chip cameras, or eyepieces with wide apparent fields. If you want maximum versatility, minimal edge darkening, and future-proof compatibility for imaging, the B1800 is the way to go.
Observing Tip:
If you plan to image the Sun using a monochrome camera with a larger format sensor, the B1800 is essential for minimizing vignetting. It’s also a great choice for high-magnification solar work where edge clarity matters. Give the telescope time to thermally stabilize before observing for best results.
Optical Excellence
At the heart of the LS100MT is a 100mm f/7 FPL-53 ED triplet lens that delivers outstanding color correction and contrast. It’s well-suited for hydrogen-alpha solar detail, lunar and planetary observing, and wide-field nighttime imaging. You'll get pinpoint stars and sharp detail from the Sun’s chromosphere all the way to globular clusters and galaxies.
Solar Observing with Pressure Tuning
The LS100MT uses Lunt's internal pressure tuning system to fine-tune the bandpass of the built-in hydrogen-alpha etalon. Pressure tuning allows you to shift the central wavelength and reveal different layers of solar structure, such as prominences, filaments, and surface granulation. Unlike tilt-tuned designs, this method keeps the field evenly illuminated and helps prevent sweet spots.
Important Safety Warning:
Never look at the Sun through this telescope—or any telescope—without the hydrogen-alpha etalon and blocking filter properly installed. Permanent eye damage or blindness will result. The telescope must be used exactly as designed for safe solar observing.
Dual-Purpose Design for Day and Night
As a modular telescope, the LS100MT transforms easily from a dedicated solar scope into a high-performance nighttime refractor. Remove the hydrogen-alpha module and install the included standard focuser assembly to use the telescope for planetary, lunar, or deep-sky observing. The f/7 focal ratio and color-pure triplet optics make it a powerful all-around instrument for any sky condition.
Mechanical Features
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100mm FPL-53 ED triplet optics
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714mm focal length (f/7)
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Internal pressure-tuned hydrogen-alpha etalon
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2" B1800 blocking filter in diagonal housing
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Modular rear cell for fast conversion between modes
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2" Rack & Pinion or Feather Touch focuser (depending on configuration)
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Vixen-style dovetail bar and hinged rings with solar finder handle
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Custom foam-lined hard case for safe storage and transport
What’s Included:
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Lunt 100mm FPL-53 ED triplet optical tube
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Internal pressure-tuned hydrogen-alpha etalon system
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2" B1800 blocking filter in diagonal
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Rear focuser assembly (Crayford or Feather Touch)
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Ring set with dovetail and integrated solar finder handle
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Hard foam-lined carry case
