TeleVue Paracorr Type 2 BIG 3″ – Coma Corrector

TeleVue Paracorr Type 2 BIG 3″ : Coma corrector: comacorrector voor parabolische Newtons

The Paracorr BIG is the 3-inch version of the Type 2, developed for large Dobsons and astrographs with a 3-inch focuser. The larger clear aperture prevents vignetting where the 2-inch version hits its limits.

The correction is the same: parabolic mirrors up to f/3, with a factor of 1.15.

Why a Newtonian telescope has coma

A parabolic primary mirror images only the center perfectly. Toward the edge, stars acquire a comet-like tail: coma. The faster the mirror, the smaller the sharp center; at f/4, that is only a few millimeters.

No eyepiece can fix that, because the error originates in the mirror. A corrector in the light path can, however. The Paracorr corrects the coma and leaves the rest of the image unaffected.

For large mirrors and large sensors

With Dobsonians from about 500 mm aperture upwards, the fully illuminated field circle of a 2-inch corrector becomes tight, certainly with eyepieces like the 21 mm Ethos. The 3-inch aperture solves that.

For photography, the BIG serves sensors up to full-frame format, provided the focuser and the rest of the optical train maintain the 3-inch standard.

Featured accessories

The Paracorr is the permanent partner of Ethos and Nagler eyepieces on fast Dobsons: especially with 82 and 100-degree fields of view, you see the edge, and therefore the coma. With the corrector, stars are point-like right into the corners.

For whom yes and for whom no

• Dobsonians with a 3-inch focuser and large aperture
• ✓ Astrophotography with large sensors on a fast Newtonian
• ✓ How to detect vignetting on the 2-inch version
• ✗ Telescopes with a 2-inch focuser, that is what the Type 2 is for
• ✗ Non-parabolic optics

Specifications

You can find the complete product line for this merk at the TeleVue merk Page.