TeleVue Paracorr-2 User manual

Model VIP-2010 (Visual-Imaging-Paracorr)
BACKGROUND
All Newtonian/Dobsonian telescopes can benefit from using a Tele Vue Paracorr (Parabola Corrector)
to eliminate 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). While a Newtonian/Dobsonian
telescope will benefit from the use of Paracorr, those faster than f/5.0 will see the greatest results.
Stars at the edge of the field will improve so dramatically, that when using top-notch Tele Vue
eyepieces an object will be equally sharp 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.” Just insert Paracorr 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 combined with Tele Vue eyepieces.
The Paracorr Type-2 allows an f/3 parabolic mirror to perform like an f/12 without it. This permits development
of a new generation of larger ladderless Dobs, with bigger, sharper fields than ever before. Indeed, it's already been
successfully applied by Mike Lockwood to his 20" f/3 and 14.5" f/2.55!
This model Paracorr is dual function: the tunable top permits positioning all Tele Vue eyepieces for optimum
performance (see eyepiece position chart on the other side), and the optical assembly can be removed for use in an
imaging system with DSLR or CCD cameras along with Tele Vue Imaging System accessories.
VISUAL INSTALLATION
For visual use: Paracorr simply slips into your focuser like a 2" Barlow. Depending on eyepiece
typeandsetting,you will need about 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) Remove 1¼" adapter.
3) Slip 2" eyepiece into the Paracorr
4) Tighten eyepiece lock screws (A)
5) 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 on other side.
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 acci-
dentally use the tuning feature for focussing.
The easiest method for finding optimal correction 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.
FOR IMAGING APPLICATIONS
1) Back off set screw under flange (D) so you can unscrew lens assembly.
2) For use with DSLR cameras (APS size chips recommended, as full-size chips will show vignetting). Tele Vue Canon
Wide-T Adapter CWT-2070, or Standard T-Ring Adapter TRG-1072 attaches directly to the Paracorr Type-2 flange.
3) For CCD cameras, use Tele Vue Imaging System accessory tubes with Tele Vue camera adapters, or A2A-1107
adapter for cameras with 2" nosepieces. Best back focus is approximately 55mm from flange face.
32 Elkay Dr., Chester, New York 10918 (845) 469 - 4551 www.televue.com
TeleVue
Visionary
PARACORR TYPE-2 INSTRUCTIONS
A
BC
A
C
D
A
B

Paracorr TyPe 2 eyePiece PosiTion charT
Position A B C D E F G H
2" Oculars
(Dist. from Ref.) -0.4" -0.3" -0.2" -0.1" 0" +0.1" +0.2" +0.3"
31mm N T5
17mm Ethos
21mm Ethos
22mm N T4 17mm N T4
26mm N T5
35mm Pan
20mm N T5
41mm Pan
27mm Pan
13mm Ethos
10mm Ethos
3.7mm Ethos
(w/incl. adptr)
1¼" Oculars
(Dist. from Ref.) 0" +0.1" +0.2" +0.3" +0.4" +0.5" +0.6" +0.7"
8mm Ethos
6mm Ethos
32mm-to-8mm Plössls
Radians (all)
24mm Panoptic
19mm Panoptic
16mm Nagler Type 5
Nagler Type 6 (all)
2-4mm Nagler Zooms
3-6mm Nagler Zooms
3.7mm Ethos
12mm Nagler Type 4
40mm Plössl
"A" Position "E" Position
(neutral offset)
"H" Position
2" to 1¼"
adapter
Tunable Top
Paracorr Type 2
Lens Assembly