ZWO FF90 f/6.8 APO REFRACTOR Dew heater 99x field flattener for the

99x field flattener for the TSA-120

the backlash varies along different points of the worm drive and generally also increases overtime

workbenches and shelf storage

CaF2 has got an impressive refractivity which enables construction of the ultimate lens system that can deliver an incredible amount of sharpness across a very broad spectral range

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ZWO FF90 f/6.8 APO REFRACTOR Dew heater 99x field flattener for theThe ZWO FF90 is an apochromatic quadruplet flat field astrograph that offers high performance for an exceptionally low price. The quadruplet design makes it perfect for both visual observation and astrophotography. The objective lens features an element of extra low dispersion glass (ED) that minimizes chromatic aberration. The ZWO FF90 is a versatile instrument and excels not just at imaging, but as a grab & go visual telescope. The OTA itself weighs