TeleVue Radian 5mm

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Brand and Model:TeleVue Radian 5mm
Price ($USD):$240.00
Type:Misc Wide Angle
Focal Length:5 mm
Barrel Size:1.25 in
Apparent FOV:60.0 degrees
Field Stop Dia.:5.3 mm
Eye Relief:20 mm
Elements:7
Weight (lbs):0.5
Description:

Vote Highlights Vote
TeleVue Radian 5mm
Well, this is my first Radian, and sure, it's a real winner. I can find only two real "faults", a loose instadjust and slight lateral colour. For me, instadjust is not a problem, but I understand the complaints about that. It would be great if Al put a nylon screw to block the thing in a fixed position. I don't need the pupil guide, and this ep don't really have kidney bean, and I know KB, I have several Konigs.
The other "fault" is lateral colour, and again, not really a real fault. In my scopes, about 55º of the 60º apparent field were simply perfect, with no noticeable EP aberrations. The rest 5º have a increasing lateral colour, with little geometrical aberration. For planets and bright objects, 55º perfection, with another 5º of really good geometrical performance for star fields.

Against Pentax XL 5.2, I find better contrast, a bit better geometrical correction (on and off axis, more noticeable off axis) and more lateral colour with my Radian, but I don't think the Pentax was more confortable, at least for me. Both are superb EPs, and the best would depend of personal preference, so I think it's no fair to under/overrated any of them because you like more one or another.
Tested in f/5, f/6 and f/10 scopes, newtonian, refractors and SCTs.

Overall Rating: 10
Optics:10 Value:9
Weight: 10 (Trustworthy Vote)
Date:
By:
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=69722

TeleVue Radian 5mm
Of all the varieties of Televue eyepieces , the Radians are my least favorite. As an effect of the higher magnifications , objects always seem rather dim through them , and I find myself switching to my TMB monocentrics for a brighter and contrastier view on concentrated dim objects such as planetary nebulae. The best use of this eyepiece is for planetary viewing , especially Saturn , when conditions permit the use of extreme magnifiction. This yields 200X in my Tak TOA 130. I have used it in conjunction with the TOA 1.6x extender on several occasions at 320x.

Update 12/1`5/2004: After using both a Pentax 7 XW and a TMB 6 super monocentric , I sold this eyepiece at the first opportunity. The only real advantage of the Radian line of ep's is the eye relief. I now find that in the shorter focal lengths , I am able to observe without my glasses. The TMB monocentric is MUCH better on planets , and the Pentax has a much brighter image on small globular clusters. Sayonara , Radian!

Overall Rating: 7
Optics:7 Value:7
Weight: 5 (Veritable Vote)
Date:
By:
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=335546 

>Update 12/1`5/2004: After using both a Pentax 7 XW and a TMB 6 super monocentric , I sold this eyepiece at the first opportunity. The only real advantage of the Radian line of ep's is the eye relief. I now find that in the shorter focal lengths , I am able to observe without my glasses. The TMB monocentric is MUCH better on planets , and the Pentax has a much brighter image on small globular clusters. Sayonara , Radian!

7mm vs 5mm.  You don't think there's a problem with such a comparison?  Duh.
TeleVue Radian 5mm
I have the Lanthanum 5mm for 6 months. I was very happy with this eyepiece
,but I wanted something with more field. So I decided to buy a radian 5mm which
has more field and was supposed to deliver better images of the planets. So
I have tested side by side the Lanthanum 5mm with the Radian 5mm. In my scope, a
200/1000 Newton, the details in the planets were more evident in the lanthanum than
they were in the radian. I think I have this phenomena because it's a bit more
difficult to achieve a perfect focus with the radian than it is with the lanthanum?!
The lanthanum deliver with less difficulties of focus images crisper than the radian.
So, if you don't have a good focuser, the radian will not be optimum for your scope.
This first experience with radian tell me a lot about opinions.
To buy the radian, i listen to the informations in this web site and others
about this eyepiece. The conclusions were obvious: the radian was opticaly the
winner!!
WARNING, WARNING, WARNING!!!!
It's not true. It is not the total winner in my scope. OK, it has as expected
more field of view (with a lot of color at edges), but opticaly, it's the same
as the lanthanum, for my eyes.
In my humble opinion (alias IMHO), nobody can tell that a premium eyepiece
is better than other without telling something about the scope in which
it is used.
So, if you could learn just one thing about my post: try the eyepiece you
plan to buy in your scope, and make yourself your own opinion about the
stuff. The combination scope/eyepiece is the most important thing to obtain
the best and contrasty images. The radian 5mm would certainly be a outstanding
eyepiece in some scope, but not in all of them!!! The same for the Lanthanum!!
Don't hesitate, send me some feedback.
Last word, sorry for my bad english: i'm french!

Overall Rating: 8
Weight: 5 (Veritable Vote)
Date:
By:
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=43898

TeleVue Radian 5mm
Optics: Very sharp image, no noticable color or distortion through 60 degree FOV. Without the eye guide, it is very easy to lose the exit pupil, particularly when you are scanning through an area of the sky that does not have a lot of stars. Part of the reason is that the eye lens (lens nearest the eye) is huge for a 5 mm ep. Views from slightly off axis show some kidney beaning. When conditions are good and the target is bright, images are spectacular.
Value: A bit cheaper than a Nagler, a lot cheaper than a Pentax, but still a pretty pricey hunk of glass.

Overall Rating: 9
Optics:9 Value:8
Weight: 4 (Unreliable Vote)
Date:
By:
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=133902

TeleVue Radian 5mm
Excellent high power planetary eyepiece. I have directly compared it with a 5mm Pentax SMC ortho and could see no significant difference in sharpness or contrast. There is a BIG difference in user comfort - the Radian can't be beat in this respect. Highly recommended.

Overall Rating: 10
Weight: 4 (Unreliable Vote)
Date:
By:
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=43896

TeleVue Radian 5mm
This is the first Tele Vue eyepiece that I have been disappointed with. I have used the 3 and 4mm Radians with great results, and expected much the same from this one. Instead, I found more ghosting than I have ever seen in an eyepiece. It is at its worst on Jupiter, where a diagonal line of multiple reflections runs through the planet at all times, and one or two additional free floating ghosts roam around the field of view. This happened in both an 80mm refractor and a 6 inch Maksutov. Aside from this fault, the eyepiece is optically fine, but if a 5mm eyepiece is not useable on Jupiter, it is a failure in my opinion.
Construction is good, consistent with the high cost, although I would give a slight edge here to the competing 5.2mm Pentax and the 5mm Takahashi LE.
I note again that I continue to use the 3 and 4mm Radians and find them excellent, so I don't think that my findings can be dismissed as those of an incompetent newcomer or someone with an anti-Tele Vue bias. Perhaps not everyone will see the same ghosting - it may be particular to my eyes. Still, I have good eyesight and know well enough how to set the instajust properly, so I would be surprised if I were alone in having this problem with the 5mm Radian.

Overall Rating: 3
Optics:4 Value:2
Weight: 3 (Unreliable Vote)
Date:
By:
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=193562

TeleVue Radian 5mm
Excellent,but of course it's a TeleVue. To see the true potential of the this eyepiece you really need a high quality scope. Some have complained of reflection problems (ghosting from bright objects) but I do not have the problem.

Overall Rating: 10
Weight: 3 (Unreliable Vote)
Date:
By:
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=43900

TeleVue Radian 5mm
Ecellent ep gets lots of use in my TV101.
Sharp, ghost free, great FOV.

Overall Rating: 10
Weight: 3 (Unreliable Vote)
Date:
By:
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=43895

TeleVue Radian 5mm
Another Radian winner. Sharp, lots of contrast, and no reflections or ghosting noted.

Overall Rating: 10
Weight: 3 (Unreliable Vote)
Date:
By:
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=43894

TeleVue Radian 5mm
Excellent planetary eyepiece. I'd have rated it a 10 except I'm not a fan of the click-stop eyeguard. Am planning on adding the 4mm and 3mm Radians later this year.

Overall Rating: 9
Weight: 2 (Unreliable Vote)
Date:
By:
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=43897

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