Going Big
The EdgeHD 11" represents a significant step up in aperture and focal length from the 6" Ritchey-Chrétien I had been using. At native 2800mm and f/10, with the option of a 0.7x reducer bringing it to f/7 (~1960mm), this telescope opens up small galaxies and planetary nebulae that simply cannot be resolved at shorter focal lengths.
Upgrade from the 6" RC
Moving from the Astro-Tech AT6RC to the EdgeHD 11" was driven by the need for more aperture and focal length. The 6" RC at 1370mm was excellent for larger targets, but small galaxies and planetary nebulae demanded more reach. The EdgeHD's flat-field optics eliminate the need for a separate field flattener, and the fastar-compatible secondary makes f/2 imaging possible with the right corrector.
The Focuser and Mirror Flop Problem
The focuser and mirror flop are two things the Edge scopes are burdened with that are less than stellar. The stock focuser has too much play for serious imaging at long focal lengths. I replaced it with a Moonlite CHL 2.5" large format Crayford Edge focuser — a significant improvement in stability and precision.
Imaging Train
The current imaging train includes:
- ZWO ASI174MM-Mini guide camera
- ZWO Off-Axis Guider
- 2" Astronomik L-2 UV/IR block filter
- Moonlite CHL 2.5" large format Crayford Edge focuser
- ZWO ASI071MC-Pro main camera (later upgraded to ZWO ASI2600MC-Pro)
Guiding Performance
Initial guiding results on the Celestron CGX mount showed 0.78 total RMS error with 0.71" RA and 0.33" DEC error over 15 minutes. Acceptable, but the CGX was eventually replaced with a 10Micron GM1000 HPS — a dramatically more capable mount for this weight class.
Current Setup
The most current configuration pairs the EdgeHD 11" with the 10Micron GM1000 HPS mount and Pegasus Astro Ultimate Power Box V2, with the ZWO ASI2600MC-Pro as the primary imaging camera. This combination delivers consistent sub-arcsecond guiding and reliable unattended imaging sessions.
Sample Images
Some recent images taken with this telescope:
