About the TeleVue Parracor Type II - Photo/Visual...
This photo/visual model - the TeleVue Paracorr Type II - is corrected for any parabola down to f/3. It includes a tunable top, removable lens assembly threaded to mate with TeleVue imaging system components, and a special 2" to 1.25" adaptor. Magnification is 1.15x.
An optical chain is as good as its weakest link. With the development of 82 degree Nagler TeleVue Telescope Eyepiece, Tele Vue offers the largest, flattest and best corrected visual fields in the industry. Combine the Nagler revolution, Dobsonian revolution and TeleVue Paracorr for the ideal mating for spectacular wide and sharp "spacewalk" observing.
Coma makes stars look like blurry comets whose tails point out radially from the center of the field. The faster your telescope'''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. Dedicated coma correcting eyepieces were another approach. However, these were limited to 50 degree apparent fields and would orphan your existing telescope eyepiece collection.
Televue Paracorr is a universal corrector that tightens and intensifies star images on all f-ratios from f/3.5 to f/8 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 Telescope Eyepiece, put M-13 at the edge of the field and enjoy resolving its beauty as it drifts across your view. Televue Visual Paracorr is easy to use. It slips into your focuser, just like a Barlow lens. 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 Telescope Eyepieces because our Plossls, Radians, Panoptics, Naglers and Ethos achieve higher levels of aberration correction than competitive models. However, Paracorr is also compatible with other telescope eyepiece makes. The visual Paracorr can be used with both 2" and 1.25" eyepieces. The imaging models work with DSLR and CCD camera. For visual use, slip Paracorr into your focuser like a Barlow lens, and your eyepiece into Paracorr. 1.25" telescope eyepieces will make use of Paracorr''s special low profile 1.25" reducing adapter. Paracorr is threaded for 2" TeleVue Eyepiece Filters.
Try the TeleVue Paracorr on your "DobNewt." We think you''ll agree that the revolution is complete!
As you''ve read, all Newtonian/Dobsonian telescopes can benefit from using a Televue Paracorr (Parabola Corrector) to eliminate coma in the image. One aspect to optimizing this correction is the distance of the telescope eyepieces focus point (field stop location) to the last surface of the Paracorr lens (within a small +/- tolerance of course). Typical telescope eyepieces used with fast Newtonians can have field stop locations differing by as much as half an inch. To accommodate for the differences, TeleVue developed the "Tunable Top." The "Tunable Top" permits optimized aberration control for all TeleVue Telescope Eyepieces and many others, by simply loosening a screw and rotating the Tunable Top. The eyepiece barrel height raises and lowers, allowing you to maintain the proper field stop to Paracorr lens distance.
"I have built Newtonian reflectors since my high school days and still enjoy observing with my 12" f/5.3. Knowing how the Nagler TeleVue Telescope Eyepiece complemented fast Dobsonians and Newtonians by removing eyepiece induced astigmatism, I now became intolerant of the inherent defect of coma in a parabolic mirror. I decided to try to achieve the same field quality for parabolas as reached by my Nagler TeleVue Telescope Eyepiece and 4-element refractor designs. Existing coma correctors seemed to be limited in color correction, spherical aberration and convenience in use. Paracorr (parabola corrector) uses 2 multi-coated, high index doublets, is completely color-free, center and edge, and installs like a TeleVue Barlow Lens. Coma is corrected so well, the diffraction limited field area of an f/4.5 Dob/Newt is increased 36 times!" -- Al Nagler
Be sure to check out our line of TeleVue Telescopes, TeleVue Telescope Mounts and TeleVue Telescope Accessories. Don'''t forget TeleVue Telescope Eyepieces, TeleVue Dioptrx and TeleVue Eyepiece Filters, too!
TeleVue Paracorr Type II - Photo/Visual Features...
- Universal corrector that tightens and intensifies star images on all f-ratios down to f/3.
- Paracorr can be used with both 2" and 1.25" eyepieces.
- Also works with DSLR and CCD cameras. Just unscrew the lens assembly from the Tunable Top and attach appropriate threaded accessory tubes and camera mount.
- Paracorr is recommended for use with all Tele Vue eyepieces because TeleVue Plossls, Radians, Panoptics, Naglers, Ethos and Delos eyepieces achieve higher levels of aberration correction than competitive models. However, Paracorr is also compatible with other eyepiece makes.
- Paracorr is threaded for 2" filters.
TeleVue Paracorr Type II - Photo/Visual Specifications...
Weight: 1.1 lbs.
Barrel: fits 2" focusers
Eyepieces accepted: 2" or 1.25" (includes 1.25" adapter)
Magnification (Barlow) effect: 1.15x
Warranty: Limited LifetimeTeleVue Product Number: VIP-2010