Is the CGX mount's 55 lb capacity enough for the 8" RASA and a full imaging setup?
Yes. With its 55 lb load capacity the CGX can easily handle the RASA 8, which weighs only 17 lbs, along with a camera and any accessories.
Which cameras are compatible with the 8" RASA, and why can't I use a standard DSLR?
Celestron designed the 8" RASA for color astronomical CMOS cameras, smaller CCD cameras and mirrorless cameras, optimized for sensors up to a 22mm diagonal and performing well up to 32mm. C-mount and M42 cameras attach with the included adapters; Canon and Sony mirrorless cameras need adapters sold separately. DSLR cameras cannot be used due to their large obstruction and long backfocus.
Do I need to autoguide with the f/2.0 RASA system?
Often not. Thanks to the fast focal ratio you can, in many cases, skip the autoguider completely. For an even higher level of accuracy, the CGX has a dedicated autoguider port.
Can I use the Celestron CGX 800 RASA for visual observing with an eyepiece?
No. The 8" RASA is a dedicated astrograph designed purely for imaging. The focal plane is located at the front of the optical tube where the camera is mounted. There is no provision to attach a diagonal or eyepiece for visual use.
How does the All-Star Polar Alignment on the CGX mount work without a polar scope?
It needs no polar finder scope and no view of Polaris. After aligning the mount, you select a bright star and the mount slews to where it would be if accurately polar aligned. You then center the star using the mount's latitude and azimuth adjustments, not the hand control. The procedure can usually be completed in about 15 minutes.
How do I get the correct 25mm or 29mm back focus for the 8" RASA?
The correct back focus depends on the adapter you use. The 29mm distance is measured from the top surface of the main lens group collar. The 25mm distance is required when you use the included M42 camera adapter. You may need to add optional M42 extension rings between your camera and the adapter to achieve this precise spacing.
What is the purpose of the removable optical window on the 8" RASA?
With super-fast optics, adding an extra piece of flat glass such as a filter changes optical performance. The 46mm optical window is removable, so you keep peak performance when a filter is added or the camera has its own window. Celestron's Light Pollution Imaging Filter for the 8" RASA mounts in place of the window.
Is the CGX mount suitable for a permanent observatory setup?
Yes. The CGX mount is well-suited for permanent installations. Its remote-operation features, such as home and limit sensors and internal cabling, were designed for remote operation. The "Hibernate" function allows the mount to be powered down without losing its alignment, making it easy to start a new session on a subsequent night.
