Double Stack Filter for Lunt 80 mm & 100 mm Universal Telescopes

Double Stack Filter for Lunt 80 mm & 100 mm Universal TelescopesSFPT Internal Double Stack Module For Lunt LS80MT & LS100MT Universal Day and Night Telescopes. Now with new generation etalons every unit individually tested on Lunt's precision metrology equipment. Every specification is verified, not estimated. The SFPT is the internal double stack module for Lunt's 80mm and 100mm Universal Modular Telescopes. It adds a second precision etalon inside the telescope body, reducing combined system bandpass from 0. 45

SFPT — Internal Double Stack Module For Lunt LS80MT & LS100MT Universal Day and Night Telescopes.

Now with new-generation etalons — every unit individually tested on Lunt's precision metrology equipment. Every specification is verified, not estimated.

The SFPT is the internal double-stack module for Lunt's 80mm and 100mm Universal Modular Telescopes. It adds a second precision etalon inside the telescope body, reducing combined system bandpass from 0.45Å single-stack to <0.28Å — without altering the telescope's external dimensions, balance, or night-sky capability.

The improvement in chromospheric contrast at <0.28Å is immediate and significant. Surface detail that single-stack views render as texture separates into discrete structure. Plage boundaries sharpen into defined cellular networks. Filaments reveal dark cores and complex multi-strand architecture. Active regions display the full depth of their magnetic complexity. Prominences show internal threading and flow patterns that single-stack instruments at this aperture simply cannot resolve.

The SFPT is designed for customer installation — no factory return required. It can be purchased at the time of telescope acquisition or at any point thereafter, making the DS upgrade a genuine deferred investment rather than a permanent commitment at point of sale. The module includes dual independent Doppler True tuning knobs — one for each etalon — allowing precise independent control of bandpass position for optimum contrast on any target.

Specifications

• Model: SFPT — Internal Double Stack Module
• Compatible With: LS80MT Universal Telescope | LS100MT Universal Telescope
• Single Stack Bandpass: 0.45Å (telescope internal etalon)
• Module Etalon Bandpass: 0.4Å — individually verified
• DS Combined Bandpass: <0.28Å — SFPT (0.4Å) + MT internal PT (0.45Å)
• Tuning: Dual independent Doppler True Barometric pressure tuning
• Installation: Customer-installed — no factory return required
• Night Sky Use: No impact — internal module does not affect night configuration