Tele-Vue Paracorr

Ratings:Top:Astronomy:Equipment Reviews:Misc Accessories:Tele-Vue Paracorr

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Brand and Model:Tele-Vue Paracorr
Price ($USD):$265
Type:Coma Corrector
Description:Not an eyepiece. A very interesting accessory that transforms even the finest Newtonian optical systems into refractors. I'd be very interested in what other folks think of this very fine and in my opinion, worthwhile accessory.
Vote Highlights Vote
Tele-Vue Paracorr
I bought the Visual Paracorr with the built-in tunable top. I own a 10" f4.8 reflector. With the Paracorr, it becomes an effective f5.5. To summarize, I think it is a MUST for 8" and larger dobs with f/6 or faster focal ratios.

Here are my notes:

Pros:
- Neatly eliminates coma. Only a little is left near the edge of FOV in my Pentax XL 40 - and that could be my astigmatism in my eyes. With shorter focal length eyepieces, it is good right out to the edge :)
- Tunable top. Provides for accurate spacing between paracorr lens elements and eyepiece. The Lumicon coma corrector doesn't have this feature, I think.
- On-axis performance very good but there is noticeable light loss due to extra 15% magnification. If you compensate by using a slightly longer focal length eyepiece, the view is virtually indistinguishable from those without a paracorr.
- Fit and finish is superb. Typical Televue quality.

Cons:
- Extra 15% magnification results in slightly dimmer views.
- Requires about 0.5" of infocus. I had to get a shorter profile focuser because of this.
- Heavy, at 1lb, it causes balance problems on light dobs like mine.
- Rather expensive. Costs almost as much as a Nagler

Overall Rating: 9
Performance:9 Value:9
Weight: 10 (Trustworthy Vote)
Date:
By: schung
Link to this vote: http://excelsis.com/1.0/displayvote.php?voteid=355315

Tele-Vue Paracorr
An absolute MUST for a fast reflector, but requires some knowledge of use. The focal plane of the eyepiece must be positioned at the correct distance from the Paracorr optics, otherwise it can actually make things worse. I am guessing that this is the source of difficulties described in the previous review detailing different eyepiece combinations. This is also why Tele Vue came out with the tunable top for the Paracorr.

In any case, the Paracorr dramatically improvemes my 12.5" f/5 reflector with all of my eyepieces. In particular, the Paracorr/27mm Panoptic combination is deep sky heaven! I also use the Paracorr at high power, such as with my 8mm Radian, with no on-axis degradation at all.

Overall Rating: 10
Weight: 3 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.127.253)
Link to this vote: http://excelsis.com/1.0/displayvote.php?voteid=44132

Tele-Vue Paracorr
I have used a Paracorr in my 13.1 f4.4 scope for several years. It does improve the sharpness of edge stars in my low to medium power eyepieces.

The reason I am marking it down is the discovery of a better option. I just purchased a Lumicon Coma Corrector. Advantage NO MAGNIFICATION. It's always bothered me that I pay a lot of money for Nagler eyepieces to get wide fields of view only to throw away 15% by magnifying it in the Paracorr.

We recently compared the two and while both did very well on coma the unmagnified view in the Lumicon was preferable.

Keep in mind that the Lumicon will not work as a convienient accessory like the Televue. I unscrew the lens cell and mount it INSIDE MY FOCUSER to use it. If you slide it into your focuser the way it comes you'd need 2-3 inches of intravel.

Before the Lumicon I would have given the Paracorr a 10 but now that I have something to compare it to it's a 7.

The Lumicon on the other hand gets a 10 for performance.

Overall Rating: 7
Performance:6 Value:7
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.47.8)
Link to this vote: http://excelsis.com/1.0/displayvote.php?voteid=301194

Tele-Vue Paracorr
I love the Paracorr in my 18" f/4.2 dob, and consider it an essential accessory. I never find the need for it in my f/5.4 Dob though. Stars become pinpoint across the field, at least in premium eyepieces like the Panoptics and Pentaxes.Value is in the eye of the beholder, and in my eye this rates a 10 for value...but nothing is perfect, so I can't give it an overall 10.

Overall Rating: 9
Performance:9 Value:10
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.238.6)
Link to this vote: http://excelsis.com/1.0/displayvote.php?voteid=154353

Tele-Vue Paracorr
The paracorr does not turn a Newt into a refractor as the descriptin above states. It corrects coma in f5 and lower newt scopes.

Overall Rating: 10
Value:10
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.85.68)
Link to this vote: http://excelsis.com/1.0/displayvote.php?voteid=55343

Tele-Vue Paracorr
If you see a scope with one in it, ask to look with and without. It works.

Overall Rating: 9
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.165.61)
Link to this vote: http://excelsis.com/1.0/displayvote.php?voteid=44134

Tele-Vue Paracorr
I own a 1.25 inch visual Paracorr and it really kills those "seagulls" in my Celestron Comet Catcher at f 3.64.My buddy has an 18 inch f4.5 Nova mirror in his Obsession and it does not do much extra in that(maybe due to laser collimation being so easy and exact.

Overall Rating: 9
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.94.7)
Link to this vote: http://excelsis.com/1.0/displayvote.php?voteid=44133

Tele-Vue Paracorr
The Paracorr seems to work well only with the mid to low power, better quality eyepieces. Following is what I found using various eyepieces in my 14.5inch dob, using the old version Paracorr (i.e no tunable top).

40mm 2 inch Konig - Image improved in the centre, but worse at the edges.
40mm Meade 1.25inch SuperPlossl – Image improved across the entire field.
32mm 1.25 inch cheap Plossl – Image slightly improved in centre, but worse at edges.
26mm Celestron Plossl - Image slightly improved in centre, but worse at edges.
20mm Erfle from Pocono Mountain - Image worse across the entire field, seemingly astigmatic.
16mm Widescan – Image pretty awful, but it was pretty awful without the Paracorr.
14mm Meade Ultrawide – Image amazingly sharper across 90% of the large field.
My higher power eyepieces - I couldn’t really tell any difference in image quality.

Thus I found the most eye catching improvement to be in my 14mm Meade Ultrawide, an eyepiece which I previously had thought was brilliant anyway in that telescope. And the only other improvement of the type I expected was in the 40mm Meade Superwide. The only conclusion I can draw from this limited test is that the Paracorr does indeed work as advertised, but only with very good edge quality eyepieces. While I had not been expecting too much improvement from the Konig and Erfle, I was surprised at the lack of improvement in the plain Plossls. However, I had previously read that most cheap Plossls sold are not of the real Plossl design, but are of the similar double symmetrical design. Perhaps this was the cause of what I observed.

So I find it difficult to rate the Paracorr. Its performance on good eyepieces warrants a rating of 10. But the result on cheaper eyepieces was disappointing - even though the fault lies with the eyepieces. Hence my rating of 8.

If you are thinking of getting a big dob with premium quality eyepieces, then get a Paracorr. But it is important that you carefully plan your eyepiece selection. According to Nagler, the ideal exit pupils for your telescope will be 2mm, 4mm and 6mm. Thus, for example, in an f/4.5 telescope this equates to 9mm, 18mm and 27mm eyepieces. But if you are using the Paracorr, it becomes an f/5.18 telescope system, and the ideal eyepieces are 10mm, 21mm and 31mm.

Overall Rating: 8
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.231.228)
Link to this vote: http://excelsis.com/1.0/displayvote.php?voteid=44131

Tele-Vue Paracorr
Let's see - you have a Newtonian scope f/5 or faster? And you don't have a Paracorr (incredulous stare)? Why? It is by far and above the most important accessory on a fast telescope. Tightens star images dramatically with any of the 'big glass' TeleVue eyepieces. Required for the 22mm T4. Ditto for the 31mm T5, the 20mm T2 and the 13mm T1. Very useful for the 17mm T4, 16mm T2, 11mm T1 and 9mm T1. There is even some edge sharpening with the 7mm!
Have a Newtonian scope f/4 or faster? The Paracorr in-travel should be designed in. Why else would you use such a short focal length? You want wide field views of course; or in large scopes (20"+) short focal length becomes a necessity for transportability and storage. All eyepieces benefit immensely with a Paracorr at fast focal ratios, with useful fields of view across the entire eyepiece.

Overall Rating: 10
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.50.36)
Link to this vote: http://excelsis.com/1.0/displayvote.php?voteid=44130

Tele-Vue Paracorr
Bought the model with the tunable top. This is a very wothwhile accessory if you own a fast Newtonian scope up to f5. In my 12-1/2 f5 Portaball, the stars became noticably tighter. The 6 stars in the Trapezium held there sharpness all the way out to the edge of the field. Stars were noticably sharper throughout the field in 22, 27, 35 panoptics. The field seemed to flatten out. If perfection is important to you, A paracorr between your eyepiece and fast newtonian scope is a worthy investment.

JD

Overall Rating: 10
Weight: 1 (Unreliable Vote)
Date:
By: Anonymous (xxx.xxx.171.48)
Link to this vote: http://excelsis.com/1.0/displayvote.php?voteid=44129

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