What does a field flattener do?
Field flattener lenses in binoculars improve edge sharpness and lower the distortion. Field flattener lenses counteract the Petzval field curvature of an optical system. In other words, the function of a field flattener lens is to counter the field-angle dependence of the focal length of a system.
Is a field flattener necessary?
Without a field flattener stars that are not in the center will appear distorted. Spacing is critical.
What does a flattener reducer do?
Field Flatteners And Reducers Some flatteners do just that: they flatten the field removing the field curvature created by the telescope. Some flatteners are also reducers: this means that while they correct the field curvature, they also reduce the focal length of the telescope.
Is a field flattener the same as a coma corrector?
Often in the form of an accessory, like a coma corrector that when added to a newtonian corrects it’s coma, or a field flattener that when added to an SCT or to a refractor corrects it’s field curvature. Some times, the corrections are built-in the scope.
Do I need a field flattener with a crop sensor?
Typically a telescope will require about a 3 inch focuser to handle a full frame sensor and usually (a few don’t) need a thing called a field flattener to enable the stars to be pinpoints in the corners of the image.
What is an adjustable field flattener?
The Apertura Adjustable Flattener is designed to flatten the photographic field when used with either the Apertura 60EDR or the Apertura 72EDR refractor telescopes and your DSLR camera. This is a full frame flattener and is threaded to accept 2″ filters.
Is a coma corrector necessary?
If you personally find the edges of your field objectionable and the cost of a coma corrector seems reasonable, go for it, otherwise, if you’re fine with what you see, then don’t.
What does a coma corrector do?
A coma corrector is a shallow lens used to correct disortions in the optical field caused by the mirrors (or is that the primary only?) Coma usually becomes annoying towards the edge of field, so if you stay well inside it is minimized.