Field Flattener 2''

The Omegon field flattener - Provides perfect image flatness for your astronomy photos

Many refractors and reflector telescopes suffer from field curvature. A curved image field means that stars at the edge of the field of view no longer appear as pin-sharp points but as out of focus discs. But now the new Omegon field flattener will conjure astronomy photos with pin-sharp stars right out to the outer edge of the image field.

Bringing the problem under control

Field curvature is a common optical defect that is not noticeable with visual observing or photography using small chips. If, however, you use a large chip or a full-frame camera, then this defect becomes glaringly obvious. Of course you could always crop your images to remove the blurred outer region; but using a field flattener it is much more elegant solution for using your expensive camera with its large format chip.

Flat field over the entire field of view

The field flattener gives you an absolutely flat image over the entire photographic field of view. Also, the focal length remains the same when using the flattener.

Suitable for telescopes from f4 to f8

You can use the Omegon field flattener with any refractor with a focal ratio between f4 and f8.

M48 thread for better aperture illumination

The Omegon field flattener has an M48 thread on both sides - giving you complete aperture illumination. A T2 thread plus M42 would limit the incoming light beam and so not provide sufficient aperture illumination for telescopes with 2" focusers. But using only the M48 thread, you make use of the entire light entering the telescope.

Use additional accessories - 109mm of back focus

This field flattener has a very generous 109mm of back focus. This means that you need a spacing of 109mm between the lens plane and the camera chip. This is an advantage, as it means you can use other accessories in between - such as a filter wheel, a flip-mirror or an off-axis guider. Using the correct Omegon extension rings will let you set the optimum spacing - whether you use accessories in between or not. Please also note the adapter recommendations in our Expert's Advice.

The advantages in a nutshell:

• field flattener for refractors
• suitable for telescopes from f4 to f8
• M48 thread for complete aperture illumination at 2"
• room for accessories between - Backfocus from 108 mm, depending on telescope focal length. At 500mm → 118mm, at 600mm → 113mm
• excellent multi-coating on lenses