Calling all Radian users

trufflehunter (Wayne Robinson) · #1 22-03-2005, 07:55 PM

I'm looking at replacing my Meade 6.4mm and 9.7mm Plossls with something better... and my little brain keeps nagging me to look at an 8mm Tele Vue Radian. I guess I'm sick of trying to look through the little pin-prick eye lenses of the Meades.

Logic, on the other hand, tells me I can barlow my GSO SuperView 15mm to 7.5mm so why bother forking out $380 for a Radian?

An 8mm Radian will give me a nice rounded figure of 250X on my LX90. I'm thinking it would become my 'work-horse' high power ep.

I've never used a Radian, and if I get one it'd be my first Tele Vue! I really like the idea of 20mm of eye relief, but have read some mixed reviews about the 'sweet spot' issue. I have a 4mm Vixen Lanthanum and it does a similar thing, although I'm used to it now. I don't use it much though... it's total overkill most nights (500X!).

I suppose I want the Radian for planets and close doubles, and I've also thought about a "volcano top" UO Ortho (certainly a much cheaper option, but doesn't give the eye relief)... oh dilemnas!

There's a beer in it for the first one to completely convince me that I really need one!

Starkler (Geoff) · #2 22-03-2005, 08:06 PM

Another option is the pentax XW 7mm , or XL 7mm second hand.
20mm eye relief, wider field and more forgiving with eye placement.

Striker (Tony) · #3 22-03-2005, 08:12 PM

Nagler 9mm.............are you convinced.....I cant say anymore.

Vermin (Tom) · #4 22-03-2005, 08:27 PM

I prefer my 5mm Radian over my 7mm Nagler, much easier to use because of the longer eye relief.

rumples riot · #5 22-03-2005, 08:30 PM

Yep 9mm Nagler.

Starkler (Geoff) · #6 22-03-2005, 08:33 PM

I wouldnt buy nagler for planetary after my comparison experiences in this thread

trufflehunter (Wayne Robinson) · #7 22-03-2005, 08:36 PM

What's the eye relief like on the Nagler? I do wear glasses, but not when using the scope... I just like a comfortable eye relief, that's why I was steering toward the Radian. Just read up on the Pentax, Geoff... sounds like a good contender too! The reviewer at Cloudy Nights described it as slightly 'warmer' than the Rad or Nag but found it very comfortable

Alik · #8 22-03-2005, 10:33 PM

hello folks,
here is my recommendation, and what essentially works for me:
- try TV Plossls, eg 20mm and/or 25mm, with a good barlow or preferably, as I use, a Powermate 2.5x. With the 20mm and PM you have a good 8mm equivalent eyepiece with, sure, a 50 degree afov, but in a driven scope and used for planets, in the real world that would be all you would need.
- I also use a 7mm t6 Nagler, which is quite superb, and its 80+ degree afov reduces nudge-intervals in my Dob.
- basically, if you have the money, and since you only live once, enjoy the feeling of buying some really nice eyepieces --- I resisted for a long time, and now regret that penny-pinching decision.

astro_south (Andrew) · #9 22-03-2005, 11:00 PM

Wayne

I have an 8mm Radian and it is my primary high power eyepiece in my dob (~238x). It also Barlows up quite nicely and gave me incredible views of Saturn at ~476x (Shory Plus 2x barlow) a while ago. I also own a 9mm 66 degree Expanse clone which I rate highly, but it just isn't in the league of the Radian. I have had no issue with kidney beaning or blackout while using this eyepiece, and it is very easy to position the eye. At this high power the field is nearly aberration free with only a slight bit of chromatic aberration at the very edge (and I mean edge) of the field as a bright star enters or exists the field. Your lx90 will track so this won't be an issue (and isn't an issue for me in my dob as it is very fleeting).

The pentax's are another good option, and I doubt you would loose much (if anything) in on-axis performance from what I have read. Some of the longer focal length Pentax eyepieces (14mm +) can show field curvature and abberations (seagulls) in fast scopes, but again this isn't an issue for you. If you purchase the 8mm Radian though, you won't be sorry. At 250x it will be used a lot - planets, multiple stars, Homunculus nebula, planetary nebula, and globs.

It was also my first TV eyepiece and I got it 2nd hand off Astromart. Since then I have also gotten a 13mmT6 Nagler and a 19mm Panoptic. These three form my primary eyepieces and one day I hope to add a 35mm Panoptic to this lineup.

Hope these ramblings help....

Andrew

ausastronomer (John Bambury) · #10 22-03-2005, 11:27 PM

The 7mm Pentax XW is a better eyepiece than the 8mm TV Radian IMO. It is not a lot dearer maybe $30 to $40. Radians give a very warm planetary image and a 60 deg AFOV, the Pentaxes give a beautiful cool (neutral) planetary image and have an extra 10 deg AFOV. The Pentax has better light transmission, contrast and sharpness by small margins. Don't get me wrong they are both exceptionally high class eyepieces but having used both a no brainer IMO, open your wallet a TAD.

CS- John Bambury

iceman (Mike) · #11 23-03-2005, 06:21 AM

Interesting thread, because a good planetary eyepiece will be next on my list after just having purchased my premium DSO eyepiece (Meade UWA14mm).

Can't wait to try the Pentax 7mm when we go observing John.

atalas · #12 23-03-2005, 08:09 AM

Man what people will do for a beer !get a 7.5 Tak LE and be done with it!

Louie

Astroman (Andrew Wall) · #13 23-03-2005, 08:57 AM

From what I can see the Radian 8mm and Pentax XW-7 are very similar. The specs below.

Pentax XW-7
- 7mm focal length
- 1.25" (31.7mm) diameter
- 70 deg. field of view
- Long 20mm eye-relief for viewing with or without glasses.
- Lens construction: 8 elements, 6 groups

Televue Radian 8mm
- 8mm focal length
- 1.25" (31.7mm) diameter
- 60 deg. field of view
- Long 20mm eye-relief for viewing with or without glasses.
- Lens construction: 6 elements, 4 groups

I guess the proof is to try out both and see what you think.

I am sure someone will let you borrow them to try

gbeal · #14 23-03-2005, 09:37 AM

Yes, sage advice, try them, all of them.
I use the LE Tak's, but would also suggest the 9mm Nagler.
For planetary I use orthos, but that is another story.
Gary

mch62 (Mark) · #15 23-03-2005, 10:17 AM

I would lean towards the Radians.
The fewer elements for planetary viewing the better is the general consensus .
Which is why Orthoscopics (4 elements) and the Monocentrics (3 elements) have been making a strong comeback with planetary observers. Simple low element low light scatter eyepieces, no wide field views here as there not needed for planetary observing.
That being said there are many dedicated planetary observers who are using Radians .They work better in faster focal ratio Newtonian than Orthos or Monos without having to use barlow's and have a better eye relief even in small focal lengths.

I have always used Othos myself for planetary use but am considering a Radian purchase in the near future when I can get a loan of one to try first.

NOW THAT'S THE POINT WITH EYEPIECES , TRY BEFORE YOU BUY IF AT ALL POSSIBLE. FORUMS ARE GOOD TO NARROW THE FIELD DOWN , BUT BEGG BORROW OR STEEL ONE FIRST BEFORE YOU BUY.
The type of eyepiece or looking at here are not cheap so you want to get it right.

Every one including myself have there idea of what is a good eyepiece, but it comes down to what you find best for your eye site and viewing habits and don't forget scope design.
The best thing to do is go along to an Astronomy nights and ask around to try eyepieces.
Most guys will be more than happy to let you have a look even if it means chaining you down so you can't run off with there favourite eyepiece.

Mark

ausastronomer (John Bambury) · #16 23-03-2005, 02:04 PM

Definately the best approach is to try and look through them and compare them, preferably in your own or a similar design scope. Eyepieces are a very subjective thing and personal preferences obviouly determine a lot of the good and bad features of an eyepiece. For instance, I mentioned that I preferred the Pentaxes because the Radians gave a "warm" image. Many observers prefer this, I don't, so you really need to try for yourself. The important thing if possible is to try and get the variables constant with both. ie targets, seeing, scope etc.

CS-John B

trufflehunter (Wayne Robinson) · #17 23-03-2005, 06:33 PM

Thanks everyone for all your great advice. It's certainly given me food for thought. Looks like it's down to the Radian/Pentax. I'd be happy with either! But the Radian is not as expensive. I've noticed a strong similarity between the Pentax design and the new Meade 5000's... mmm... interesting...
I'd really like to try out an Ortho. I used to have a Unitron 6mm Ortho and it was a nice eyepiece... but the eye relief of these newer designs is very attractive.
I like the 8mm focal length of the Rad. I think going lower (like the 7mm Pentax) might be pushing it for a 'general purpose' high power ep... it'd be more like a 'special-rare-nights-of-excellent-seeing eyepiece'.

Dave47tuc (David) · #18 23-03-2005, 08:06 PM

Geez what's the best eyepiece

What's the best car

I have used so many eyepieces I've totally lost count.

You really have to try as many as you can berfore your part with the stuff in the sky rocket

One experience i have had is a friend of mine brought a 6" Synta refractor many years ago and it was yuk to look through

But it came with a 10mm Plossll that is one of the sharpest eyepieces I have ever looked through, go figure

You don't have to buy a Tele Vue or Pentax and think this is the best.

What Radians I have used I like them but I also like Pentax's.

I use a Meade 8.8mm UWA for Planetry work and really love it. It works well because I have a 2540 FL scope. I don't need a barlow.

You will find everyone has a diffrent opinion which is great for eyepiece makers.

Good Luck.

robin · #19 27-03-2005, 11:10 PM

Hi Trufflehunter. I use a 6mm TV Radian, a 9mm TV Nagler, a 17mm TV Nagler(2") & a 35mm TV Panoptic.I love the 6mm Radian. Its my 'Saturn' EP. Eye relief is excellent, great contrast & sharpness.Thru my 10" LX200GPS, it give me 423X. Naturally, nights of good seeing support this magnification well. Average nights are so-so....I'd have no hesitation in getting another Radian.

trufflehunter (Wayne Robinson) · #20 28-03-2005, 09:19 AM

Hi Robin, thanks for that info. Interesting to read that your 10" can support a 6mm. Well, I've bitten the bullet and ordered a 8mm Radian as well as a 13mm Nagler (T6). I reckon the 8mm Radian, giving 250X on my LX90, should be right on the 'sweet spot' for an all-round high power eyepiece, without pushing any boundaries. The Nagler, at about 150X, should be perfect for nice wide field medium powers for resolving globulars etc.

I've read a few reviews from people having problems with the 'insta-just eyeguard' thing on the Radians. Some people have reported eye-placement with the long eye-relief a problem as well. Have you experienced this? I have a Vixen Lanthanum 4mm (which is overkill on the LX90, at 500X!). It has a similar eye-placement problem, with its 20mm eye-relief, until you get used to it. I have no problem with it now... it certainly beats the opposite eye-placement problem you'd experience with a 4mm Plossl!

Thanks again for the info. LX90 arrives Wednesday and the Tele Vues the following week!!! You know the feeling...