Collimating the Optics Aligning the Mirrors

1.25" nosepiece

Figure 6. To use a CCD camera with the 8" f/4.0 Newtonian Astrograph, the camera must have a 1.25" or 2" nosepiece, which is inserted into the appropriate accessory holder in the focuser. An external camera adapter with T-threads could be used in lieu of the nosepiece.

T-ring

Zero-profile camera adapter (not visible)

Figure 7. Attachment of a DSLR camera requires a T-ring for the particular camera model and a T-adapter, such as the Orion Zero-Profile Prime Focus Camera Adapter, which fits into the 2" accessory collar.

Imaging with the 8" f/4.0 Newtonian Astrograph

This instrument has fast f/4.0 parabolic optics, which pro- duce bright images and allow fairly short exposure times. Fast optics also inherently produce some coma, or distor- tion of star images toward the periphery of the field of view. Therefore, to achieve the best possible images, we recom- mend using a coma corrector (sold separately). The coma corrector is attached to the focuser drawtube in front of the camera body. Use of a coma corrector will allow you to utilize the entire imaging area of your camera without the need to crop the edges of your astro-images. Check Orion’s website for compatible coma correctors.

Attaching a CCD Camera

Most CCD cameras have a 1.25" or 2" barrel, or nosepiece, that allows attachment directly to your telescope’s focuser like an eyepiece. No adapter is required. Simply insert the nosepiece of the CCD camera (Figure 6) into the 1.25" or 2" eyepiece holder and secure the camera with the thumbscrew lock.

If your CCD imager does not include a compatible nose- piece, or if you wish to utilize the camera’s T-threads, a Zero- Profile Prime Focus Camera Adapter is required (available from Orion). The zero-profile adapter has male T-threads that couple to the female T-threads of your camera. The adapter’s 2" barrel is inserted and secured in the focuser just like a 2" eyepiece.

Attaching a DSLR Camera

To attach a DSLR camera, you will need the appropriate T-ring for the make and model of your camera and a Zero-Profile Prime Focus Camera Adapter. Simply attach the T-ring to the camera body and thread the Zero-Profile Camera Adapter onto the threads of the T-ring. Then insert the barrel of the camera adapter into the focuser’s 2" accessory collar and secure it with the two thumbscrew locks (Figure 7).

Figure 8. The 35mm extension adapter adds 35mm of length to the focuser drawtube. It is needed to reach focus for visual use of the 8" f/4.0 Newtonian Astrograph.

Visual Observing with the 8" f/4.0

Newtonian Astrograph

To achieve focus with a telescope eyepiece, you will likely have to use the included 35mm-long extension adapter (Figure 8). Just insert it into the 2" collar on the focuser and tighten the two thumbscrews to secure the extension adapter in place. Then insert either a 2" eyepiece or a 1.25" eyepiece (using the 1.25" adapter) into the 35mm extension adapter.