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BACKGROUND

All Newtonian/Dobsonian telescopes can benefit from using a Tele Vue Paracorr (Parabola Corrector) to elimi-
nate coma in the image.  Coma is the effect that makes off-center stars appear like little comets (it becomes more 
apparent as stars move closer to the edge of the field).  Any Newtonian/Dobsonian telescope will benefit from 
the use of Paracorr, but those from f/3.5 to f/5.0 will see the greatest results. For example, the size of the 
diffraction-limited field expands by an incredible 36 times in area for an f/4.5 mirror!  Stars at the edge 
of the field will improve so dramatically, that (using top-notch Tele Vue eyepieces) the image will look the same anywhere 
in the field.  It also prevents faint stars from disappearing at the edge of the eyepiece field. This is not only aesthetically 
pleasing, but it also greatly reduces the need to constantly nudge the scope to keep the object centered in the “sweet spot.”  
Paracorr essentially makes an f/4 scope perform like an f/8.  Just insert it into your 2" focuser like a 2" Barlow (it has a 
15% [1.15x] magnification factor) and add Tele Vue eyepieces to suit your needs.  It’s a recipe for perfection, when you 
use Tele Vue eyepieces.
 

This model Paracorr has the largest lenses possible to prevent any vignetting, even when using the 31mm Nagler 

Type 5.  The tunable top permits positioning all Tele Vue eyepieces for optimum performance (see 
eyepiece position chart below).

INSTALLATION

Paracorr simply slips into your focuser like a 2" Barlow. Depending on eyepiece type and setting, you will 
need just 3/8" to 3/4" focuser in-travel compared to using the eyepiece alone.

USE

For 2" Eyepieces:
1) Make sure eyepiece lock screws (A) are loosened
2) Slip 2" eyepiece into the Paracorr
3) Tighten eyepiece lock screws (A)
4) To adjust for eyepiece position, 
 

a.Slightly loosen the height adjustment lock knob (B) that clamps on the slot.

 

b. Rotate the outer barrel to adjust the height of the eyepiece, following the guidelines  

 

in the eyepiece position chart below.

 

c. Tighten the height adjustment lock knob (B).

For 1¼" Eyepieces:
1) Slip the  2" to 1¼" reducing adapter into the Tunable Top and tighten lock screws (A).
2) Place the eyepiece in the adapter and tighten the lock screw (C)
3) Follow the adjustment procedures outlined above in step 4.

NOTE

: Focus the telescope after properly setting the eyepiece position.  Do not accidentally use 

the tuning feature for focussing.
 

The easiest method for finding optimal correc-

tion for other brand eyepieces is to first establish the 
focus position with a Tele Vue eyepiece at its known 
Paracorr setting.  Then insert your other eyepiece and 
use the tunable top until focus has been reached.  
Note the mark on the Paracorr body for the setting.  
Use your telescope focuser to tweak the focus if 
necessary.

CAUTION

: Avoid using 1¼" Barlows unless you are 

certain the barrel will not contact the Paracorr lens.
 

However, you can use the 1¼" Powermates 

safely in the 1¼" adapter.  Place 2" Powermates  in 
the focuser and  the Paracorr into the 2" Powermate.

32 Elkay Dr., Chester, New York  10918   (845) 469 - 4551   www.televue.com

Tele Vue

V i s i o n a r y

 VISUAL PARACORR  INSTRUCTIONS

2" Eyepiece/Adapter 

Lock Screws (A)

Note: Guide Screws shown have been 

replaced by stainless steel button head 

screws with tension preset during as-

sembly.  No need to adjust.

Tunable Top 

Lock Knob (B)

(A)

5 4

3

2

1

(A)

(A)

(C)

(B)

EYEPIECE POSITION CHART

Set at mark 1

Set at mark 3

Set at mark 4

Set at mark 5

Set at mark 5

2" Eyepieces

2" Eyepieces

1¼" Eyepieces

2" Eyepieces

1¼" Eyepieces

 20mm Nagler Type 2 26mm Nagler Type 5  All Radians

 31mm Nagler Type 5  16mm Nagler

 Type 2**

 20mm Nagler Type 5 17mm Nagler Type 4  All Plössls through

 32mm

 22mm Nagler Type 4  12mm Nagler

 Type 2**

 13mm Nagler*

 (original)

 All 1¼" only

 Naglers (original,

 Type 5 & Type 6)

  17 & 21mm Ethos

 12mm Nagler

 Type 4**

 22mm*, 27mm,

 35mm, & 41mm

 Panoptic

 15mm, 19mm &

 24mm Panoptics

 9mm Nagler**

 (original)

 10 & 13mm Ethos

3.7, 6 & 8mm Ethos**

All Tele Vue Zooms

10 & 13mm Ethos***

   * Use only in 2" mode as listed for best correction.

 ** Use only in 1¼" mode as listed for best correction.

*** For best correction use with the Tele Vue Hi-Hat 2" to 1¼" adapter

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