instruction Manual
IN 421 Rev. A 05/11
orion Field Flattener for
short refractors
#8893
Your Orion Field Flattener for Short Refractors flattens the focal plane for astro-imaging
without affecting the focal length of the telescope. When imaging with a CCD or DSLR
camera, the far edges of the field of view are drastically sharpened when using the Field
Flattener with your fast refractor.
The Field Flattener was designed for the camera’s sensor to be 55mm away from the
T-threads at the back.
attaching the Field Flattener to a Dslr camera
A T-ring for the make and model of your camera is the only required accessory to attach
the Field Flattener to your DSLR camera. The 55mm spacing is perfectly matched when
using the T-ring (Figure 1.1).
attaching the Field Flattener to a ccD camera
Most CCD cameras require less backfocus than a DSLR camera. That means you
will need to add spacing as needed to fill the 55mm of required distance to the Field
Flattener (Figure 1.2). T-thread spacers are available from Orion. For example, the
StarShoot Pro V2.0 has 20.1mm of backfocus; so it would require adding approxi-
Field
Flattener
DSLR
camera body
T-ring
2" focuser on
telescope
Figure 1.1.
Field
Flattener
CCD
Camera
55mm
Xmm
2" focuser on
telescope
Distance from CCD
chip to Field
Flattener T-threads
should be 55mm
“X”mm of additional spacing may
be required to achieve 55mm,
depending on make and model
of camera.
Figure 1.2.