What does a field flattener do for a telescope?
A field flattener, also known as a field corrector, is an accessory used in astrophotography that helps to eliminate optical aberrations caused by the curvature of the telescope's focal plane. By attaching a field flattener to the back of the telescope, astrophotographers can significantly reduce or completely remove coma, astigmatism, and other distortions from their images. This can result in sharper, more detailed photos of distant cosmic objects such as galaxies and nebulae.
Do I need a field flattener?
Whether or not you need a field flattener for your telescope really depends on what type of astrophotography you plan to do. If you’re photographing wider-field objects such as star clusters and galaxies, then a field flattener can help to eliminate optical aberrations, resulting in sharper and more detailed photos. However, if you’re imaging planetary objects, which tend to be smaller and require higher magnification, then a field flattener may not be necessary.