The flattener is a lens that flattens the field of view as it is slightly curved by the primary optics. This curvature causes stars to be less sharp towards the edge of the image field in photographs and to be "stretched". The flattener, also called field flattening lens, corrects this error.

The effect of image field curvature is particularly noticeable with small focal ratios (e.g. f/5 to f/7) and large camera sensors (e.g. in a DSLR camera). Here, the use of the flattener is worthwhile. Astrophotographers can enjoy images in which the stars remain sharp right to the edge of the shot. The flattener is mounted between the telescope and the camera.

Mounting: The flattener is screwed tightly onto the thread of the focuser. Simply unscrew the coloured anodised end piece as shown in the picture on the right. This end piece is used to hold a socket, but is no longer needed when using a flattener. Keep it safe in case you want to use the optics visually with a zenith mirror. The flattener can then simply be screwed into the thread of the eyepiece focuser.
A T2 thread is available for mounting the camera. If you want to use a DSLR camera, use the T2/bayonet adapter that matches your camera manufacturer. At the end you have a firmly screwed system: high stability and no tilting!

The flattener is adjustable. Set the correct distance and fix it with the knurled counter ring. This way you do not need separate extension sleeves.

You can screw filters with M48 thread directly into the flattener. Simply unscrew the end piece on the camera side. This frees up an M48 thread into which you can screw the filter. Now screw the flattener back together - done!

Scope of delivery:

• Flattener