TeleVue's 3" BIG Paracorr Type-2, designed by Paul Dellechiaie, extends the Paracorr type 2's optical benefits for imaging applications by amateurs and professionals using CCD formats bigger than 30mm and as large as 52mm diagonal and paraboloids as fast as f/3. Back focal length has been extended to 80mm to allow for additional accessories to be placed in the optical path. The 5.1" length optical assembly is topped with a "stop" flange having 3.40"-24 pitch threads to mount camera adapters and spacer tubes. There is no visual advantage in using the 3" BIG Paracorr Type-2 over the 2" Paracorr Type-2.
Life without Paracorr
Coma makes stars look like blurry comets whose tails point out radially from the center of the field. The faster your scope's speed, the worse the effect. All parabolic mirrors used in Newtonian reflecting telescopes are limited in field sharpness due to coma. Even a perfectly made 13" f/4.5 parabola has only about 0.1 degree diffraction limited field.
Previous attempts to correct for coma have been limited in usefulness. Some correctors were designed mainly for astrophotography, some required difficult installation in the focuser's draw tube. Dedicated coma correcting eyepieces were another approach. However, these were limited to 50 degree apparent fields and would orphan your existing eyepiece collection.
Life with Paracorr
Paracorr is a universal corrector that tightens and intensifies star images on all f-ratios down to f/3! (see spot size graphs: PDF or JPG) without adding any false color or spherical aberration! You no longer have to constantly shift a Dobsonian to keep objects centered for sharp viewing. Using a TeleVue eyepiece, put M-13 at the edge of the field and enjoy fully resolving its beauty as it drifts across your view.
Paracorr is easy to use. It slips into your focuser, just like a Barlow. To minimize focuser in-travel, due to additional length, a mild 15% Barlow effect was designed into Paracorr to effectively push the focus out. Paracorr is recommended for use with all TeleVue eyepieces because our Plössls, Delites, Panoptics, Naglers, Ethos and Delos eyepieces achieve higher levels of aberration correction than competitive models. However, Paracorr is also compatible with other eyepiece makes.
Try Paracorr on your "DobNewt." We think you'll agree that the revolution is complete.
Paracorr Eats Coma
Paracorr can be used with both 2" and 1¼" eyepieces. For visual use, slip Paracorr Type-2 into your focuser like a Barlow lens, and your eyepiece into Paracorr. 1¼" eyepieces will make use of Paracorr's special low profile 1¼" reducing adapter. Paracorr is threaded for 2" filters.
||Fits 3" Focusers
||3.40" x 24 TPI
|Base to Flange