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Televue Paracorr Type 2 Coma Corrector for 2" Focusers

Televue Paracorr Type 2 Coma Corrector for 2" Focusers
Televue Paracorr Type 2 Coma Corrector for 2" Focusers
Televue Paracorr Type 2 Coma Corrector for 2" Focusers
-9 % Ask About Stock
Televue Paracorr Type 2 Coma Corrector for 2" Focusers
Televue Paracorr Type 2 Coma Corrector for 2" Focusers
Televue Paracorr Type 2 Coma Corrector for 2" Focusers
Televue Paracorr Type 2 Coma Corrector for 2" Focusers
£499.00
£549.00
Ex Tax: £415.83
  • Stock: Ask About Stock
  • Model: VIP-2010
  • Shipping Weight: 1.20kg
  • SKU: VIP-2010
  • MPN: VIP-2010
  • Location: F4AB4

An optical chain is as good as its weakest link. With the development of 82 degree Nagler and 100+ degree Ethos eyepieces, Tele Vue offers the largest, flattest and best corrected visual fields in the industry. Combine the Nagler/Ethos revolution, Dobsonian revolution and Paracorr for the ideal mating for spectacular wide and sharp "spacewalk" observing.

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 Tele Vue 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 Tele Vue eyepieces because our Plössls, 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.

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.

Starlight Integrated Paracorr System (SIPS)

Note: The Paracorr Type 2 optical assembly is also available in a special adapter housing made by Starlight Instruments for their Feather Touch focusers. This unit avoids the need for a tunable top to optimize eyepiece position. Some Dobsonian manufacturers may also offer the Feather Touch focuser with integrated Paracorr type 2 as standard. Starlight Instruments offers Paracorr Type 2 integrated with Feather Touch focuser or as an add-on if you already have a Feather Touch focuser.

Astrophotography

Paracorr also works with DSLR and CCD cameras. Just unscrew the lens assembly from the Tunable Top and attach appropriate threaded accessory tubes and camera mounts. See 2" Imaging (Paracorr Type-2) and 3" Imaging (3" BIG Paracorr Type-2) sections for more on Paracorr imaging.

CONCEPT

Concept: I have built Newtonian reflectors since my high school days and still enjoy observing with Dobsonians. Knowing how the Nagler 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.

Paracorr — more stars, sharper stars, more time to observe.

In 1989 I decided to try to achieve the same field quality for parabolas as reached by my Nagler 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) is completely color-free, center and edge, and installs like a Barlow. In 2009, we decided to greatly improve the correction with the Paracorr Type-2 design (followed by 3" BIG Paracorr Type-2 in 2014) so that new, large, Dobs as fast as f/3 could become practical. Ladderless Dobs with larger fields herald a revolution. Read the reviews and story, The New Dobsonian Revolution, in Astronomy magazine. The new Paracorr Type-2 is a combination visual and imaging system designed by Paul Dellechiaie and our staff. Let the revolution begin. — Al Nagler

Related Links

Ladderless Dobs with larger fields herald a revolution. Read the reviews and story, The New Dobsonian Revolution, in Astronomy magazine.

Paracorr Type 2 Instructions
Chart (PDF): Spot Size GraphsChart (JPG): Spot Size Graphs

VISUAL USE

Optimizing the Coma Correction by Using Paracorr's Tunable Top

As you've read, all Newtonian / Dobsonian telescopes can benefit from using a Tele Vue Paracorr (Parabola Corrector) to eliminate coma in the image. One aspect to optimizing this correction is the distance of the eyepieces focus point (field stop location) to the last surface of the Paracorr lens (within a small +/- tolerance of course). Typical eyepieces used with fast Newtonians can have field stop locations differing by as much as half an inch. To accommodate for the differences, we developed the "Tunable Top."

The "Tunable Top" permits optimized aberration control for all Tele Vue 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. For your reference, here is a recommendation guide for choosing the best setup for various Tele Vue eyepieces to get optimum correction:

Table for 3" BIG & 2" Paracorr Type-2 (VIP-3010/2010)
PositionABCDEFGH
2" Oculars
(Dist. from Ref.)
-0.4"-0.3"-0.2"-0.1"0"+0.1"+0.2"+0.3"
Panoptic      3541 & 27
Delos        
Nagler Type 4 22   17  
Nagler Type 531    2620 
Nagler Type 6        
Nagler Zooms        
Ethos21 & 17      13, 10,
3.7SX & 4.7SX
(w/2" adapt.)
         
         
1¼" Oculars
(Dist. from Ref.)
0"+0.1"+0.2"+0.3"+0.4"+0.5"+0.6"+0.7"
Plössls
 
  32-to-8   40
Radian   all    
DeLite   all    
Panoptic   24 & 19    
Delos17.3 & 14  12-to-3.5
17.3* & 14*
    
Nagler Type 4   12    
Nagler Type 5   16    
Nagler Type 6   all    
Nagler Zooms   2-4 & 3-6    
Ethos 8 & 6 3.7SX & 4.7SX    
*Use at "D" with AIT-2125 In-Travel Adapter.
All eyepiece interfa...
All eyepiece interfaces have non-marring brass clamp rings.
IMAGING USE OF THE 2" VERSION
Paracorr Type-2 for 2" Focusers

Mount your DSLR or CCD to the Paracorr Type 2 lens assembly and the quality of full frame photos will be spectacular since star image sizes on the image plane can be less than .001" over the full frame for an f/4.5 mirror. Edge-of-field sharpness is further enhanced since Paracorr also acts as a field-flattener. Works on all f-ratios f/3 and slower without adding any false color or spherical aberration! See spot size graphs: PDF or JPG. NOTE: Curves shown are typical for mirror focal lengths in the 1200mm or longer focal length range. For focal lengths shorter than 1200mm, you might find some field curvature. In general, we recommend APS size formats, which would typically yield 90% illumination over a 30mm diagonal chip.

The Paracorr Type 2 allows separating the optical assembly from the Tunable Top and using it with Tele Vue imaging system components to permit use with SLR and CCD cameras. APS size formats 27mm diameter are recommended to minimize field vignetting. Ideal for mirrors as fast as f/3.

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