TeleVue Radian 8mm

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Brand and Model:TeleVue Radian 8mm
Price ($USD):$240.00
Type:Misc Wide Angle
Focal Length:8 mm
Barrel Size:1.25 in
Apparent FOV:60.0 degrees
Field Stop Dia.:8.3 mm
Eye Relief:20 mm
Elements:6
Weight (lbs):0.5
Description:

Vote Highlights Vote
TeleVue Radian 8mm
I had a chance to use an 8mm Radian on a 20" f/5 Obsession the other night. In isolation, it's a very nice eyepiece--sharp across the field, excellent contrast, and a nice wide field of view. Where it falls down, unfortunately, is when it's compared against the Pentax XL.

Relative to the Pentax XL, the Radian has more lateral color, perhaps slightly less contrast, a narrower field, and much more critical eye positioning. The Radian blacks out unless your eye is dead center, whereas the Pentax makes it much easier to get and hold the exit pupil. On that basis, giving the Pentax XL a 10 optically, the Radian deserves an 8. Other than for use in a binoviewer, I can't see any reason to choose a Radian rather than a Pentax XL.

As far as value, the $218 Pentax XL beats the $240 Radian in every respect except for size and weight, which makes it difficult to assign a very high number for value to the Radian. I gave the Radian a 4 for value, but that's kind of arbitrary. For many people, it would deserve a 0 relative to the Pentax XL. Why pay more for an eyepiece that's at best a step behind the Pentax? For others, like those who want to use a binoviewer or have balance problems, the Pentax XL might not be an option and the Radian would therefore deserve a much higher value rating.

Overall, I'll give the Radian a 6. If the Pentax XL didn't exist, the Radian would definitely deserve a 9 or a 10, but the Pentax XL does exist, which puts the Radian in second place.

Overall Rating: 6
Optics:8 Value:4
Weight: 10 (Trustworthy Vote)
Date:
By:
Link to this vote: http://excelsis.com/1.0/displayvote.php?voteid=68641 

That's right this is about Radians not Naglers which are indeed revolutionary. It is a valid point that the XL beats the Radian. Now both have a challenger in the TMB/BO Planetary. LP kills digital!
Reply...  (again)... This review is about the Radian, not about Pentax eyepieces....  There are a select group of TeleVue haters out there.... Stick to your Pentax.... Anyone with a brain in their head knows that TeleVue is revolutionary in its approach to optics...  People are turned off by the expense, but once you look through an Al Nagler product you're hooked.  The Nagler 9 was my first and it is NOT matched by ANY other design I've ever tried in that focal length..bar none.
Including ORTHOS... This reminds me of audio freaks sticking to LP....Face it.... Digital beat the Analog Star !!
TeleVue Radian 8mm
Altho' the Radian EP's have excellent eye relief and true FOV , they do not seem to be as sharp and contrasty as the TMB Monocentrics. I have used this EP to view Saturn at 125X in my 'scope with reasonable satisfaction , and it works fairly well on globular clusters (M15 and M79 , for example). Even tho' it is not one of my favorites , I still consider it as a "keeper".
Update 4/18/2005: In comparison to my SMC Pentax 7 XW, this e.p. comes in a distant second place. My biggest knock on this 8 mm eyepiece is a lack of sharpness and some lateral color at the edges.
I am now planning on selling this one to expand my Pentax collection!

Overall Rating: 6
Optics:7 Value:7
Weight: 5 (Veritable Vote)
Date:
By:
Link to this vote: http://excelsis.com/1.0/displayvote.php?voteid=332287

TeleVue Radian 8mm
I own the 8mm and 4mm Radians and find both EP's Outstanding in color rendition and sharpness. The instajust can be a pain sometimes due to constant readjusting for "many eyes" when at a starparty. Plenty of eye relief of course, and the images are razor sharp through my teleVue 76mm APO. Personally love this EP for views of Jupiter and it's moons at x60, and the Lunar lanscape is quite breathtaking with this EP, even more with the 4mm Radian. Not as bright and contrasty as my UO Ortho 6mm at x80, but sharper and and finer detail noted. All in all a very good EP, I think the price is a little high when there are so many other EP's that give views almost as good for a fraction of the price...but then again, it's a TeleVue :

Overall Rating: 9
Optics:9 Value:7
Weight: 5 (Veritable Vote)
Date:
By:
Link to this vote: http://excelsis.com/1.0/displayvote.php?voteid=238149

TeleVue Radian 8mm
Excellent performance; sharp right out to the edges. Slight amount of lateral color. Contrast as good as my UO 12.5mm but with a significantly wider field and 20 mm of eye relief. Eye positioning is critical or blackout occurs. Personally don't find that to be a major issue.The supplied pupil guide helps.
Most nights the 8 mm Radian on my 8 inch Meade LX50 is my personal favorite for viewing Saturn or Jupiter. Highly reccomended.

Overall Rating: 9
Weight: 4 (Unreliable Vote)
Date:
By:
Link to this vote: http://excelsis.com/1.0/displayvote.php?voteid=43721

TeleVue Radian 8mm
I have my 8mm TV Radian for 6 months now (I also own the 6mm, 4mm and 3mm).
There's not much to be added. It's a superb eyepiece period, sharp to the
edge, contrasty and bright. It's got great eye-relief and nice 60d AFOV.
This is my most-often used eyepiece for viewing globular clusters (110x)
with my TV-102 APO. Of course, the view is great for other DSOs as well.

Highest rating!
Ron B[ee]

Overall Rating: 10
Weight: 3 (Unreliable Vote)
Date:
By:
Link to this vote: http://excelsis.com/1.0/displayvote.php?voteid=43719

TeleVue Radian 8mm
Compared this Televue line of Radians to the Pentax Xl's. Sorry Al, the Pentax win hands down. The Radian is a very well corrected eyepiece as is the Pentax. Contrast is the same for both eyepieces. Placing your eye up against the eyecup and trying to keep it perfectly centered spells defeat for the Radians. They are just to hard to use... If I have to use a cardboard centering device - this eyepiece is not for me. The problem became very evident when one night we had a public observing session. I pulled out my new radians, stuck them into my AP refractor - everyone complained they could not " see anything ". I realized what these novices were talking about. I switched to the 13 Nagler - problem solved. Sold all 4 of my Radians.

Overall Rating: 5
Weight: 3 (Unreliable Vote)
Date:
By:
Link to this vote: http://excelsis.com/1.0/displayvote.php?voteid=43718

TeleVue Radian 8mm
I love this eyepiece. I seem to have had very good results with every Radian I've tried including the 7 element ones that trouble some people with reflections, but this one is the best of the lot I think. Excellent high power views in my C9.25 giving 294x but also works very well in all my other scopes including f/5 achromat. I also have the Takahashi 7.5mm and can't let either go, they are both superb. The additional eye relief and field of view of the Radian makes it a very comfortable eyepiece and the sharpness and contrast are just as good as the Tak IMO.
I would take the Radians over similarly sized Naglers every time as the extra contrast and sharpness are more important to me than an 82ยบ field of view. Don't get me wrong, I do like Naglers, but I think the Radians are the best eyepieces TeleVue have done period.
If you're considering an eyepiece around this focal length, you can't get better than this.

Overall Rating: 10
Weight: 3 (Unreliable Vote)
Date:
By:
Link to this vote: http://excelsis.com/1.0/displayvote.php?voteid=43714

TeleVue Radian 8mm
I now have the 8 and 10mm Radians, and all I can say is WOW! I find this 8mm slightly better than the 10mm. I seems to have virtually no off axis color.
Highly recommended.

Overall Rating: 10
Weight: 3 (Unreliable Vote)
Date:
By:
Link to this vote: http://excelsis.com/1.0/displayvote.php?voteid=43713

TeleVue Radian 8mm
I really rate this eyepiece a 9.5 It is a excellent eyepiece. The sharpness and contrast are fantastic! Al Nagler says that the new nagler eyepieces are equal to the radians in contrast. I disgree, the radians, in my opinion have the best contrast of any televue eyepiece ever made. Keep up the good work Al!

Overall Rating: 9
Weight: 3 (Unreliable Vote)
Date:
By:
Link to this vote: http://excelsis.com/1.0/displayvote.php?voteid=43711

TeleVue Radian 8mm
My favorite Radian - the 8mm. Contrast is a hair less than my wonderful Pentax Ortho's, but everything else is excellent - eye relief, fov, sharpness. In my opinion one of the best eyepieces from TeleVue.

Overall Rating: 10
Weight: 3 (Unreliable Vote)
Date:
By:
Link to this vote: http://excelsis.com/1.0/displayvote.php?voteid=43710

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