Hubble at Home
The Astro-Tech AT6RC is probably the most economically viable Ritchey-Chrétien telescope money can buy at roughly $350. Its dual-hyperbolic mirror design eliminates coma and delivers a flat, well-corrected field — the same optical design used in the Hubble Space Telescope, scaled down to a manageable 6-inch aperture.
Optical Specifications
At native f/9 the AT6RC has a focal length of 1370mm. With an Astro-Physics CCDT67 telecompressor, it operates at approximately f/6 with a ~915mm focal length — a much faster system for deep-sky imaging on the Celestron AVX mount.
- Aperture: 6 inches (152mm)
- Native focal length: 1370mm at f/9
- With AP CCDT67: ~915mm at f/6
- Weight: ~13 lbs (18–20 lbs with full imaging gear)
- Optical design: Ritchey-Chrétien (dual hyperbolic mirrors)
Imaging Equipment
The full imaging configuration includes:
- Celestron AVX mount (30 lb max payload)
- Orion 60mm guide scope
- ZWO ASI1600MM-Cool (primary imaging camera)
- ZWO ASI224MC (guiding)
- Astro-Physics CCDT67 telecompressor
- ZWO 8-position electronic filter wheel
- Astrodon LRGB and narrowband filters
- Moonlite CSL focuser with stepper motor
Achieving Proper Polar Alignment
At these focal lengths, precise polar alignment is crucial. Even small alignment errors become visible in long exposures at 1370mm. The Celestron AVX's built-in polar alignment routine combined with plate-solving through EKOS provides reliable results.
Sample Images
The AT6RC proved to be an exceptional value for deep-sky astrophotography. Its Ritchey-Chrétien design delivers sharp, well-corrected images across the field — remarkable for a telescope at this price point. It served as my primary imaging scope before upgrading to the Celestron EdgeHD 11".