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Radians or Hyperions?


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Looking at getting a set of three EP's. I've decided what focal lengths I'm going for but was wondering if anyone has views on which ones to go for.

A few things to consider, because of the current deal that is available on the Radians a set of 3 only works out about £40 more than a set of 3 Hyperions.

The Hyperions have a 68 degree fov whereas the Radians only a 60 degree fov.

I've heard about the Hyperion fine tuning rings but am not 100% on what they do.

If I go for the Radians I would go for the 18mm, 12mm and 8mm.

If I go for the Hyperions I would go for the 24mm, 17mm and 13mm.

Edited by Doc
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With the Hyperions, you can change the ep focal length with the two fine tuning rings - it's like having 3 ep's in one. I have the 24mm-8mm zoom, 17mm, and 8mm plus both rings which fit them all giving a great range.

Wish I'd known the Radians were coming up on offer - I allready have the 12mm, 8mm, and 5mm. Although slightly less wide they are superbly clear, no noticeable drop off at the edges (imo), good eye relief, and can't really fault them.

My ranges overlap cos it gives me alternatives depending on what I'm looking at, and prevailing conditions. Plus the Hyperions are directly attachable to my camera.

Hope that helps ;)

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Thanks for the reply. So if push came to shove would you use your 8mm Hyperion or 8mm Radian? Would you pick a wider view over a clearer narrower one?

Also how do these tuning rings work? Is it an easy enough thing to do whilst your viewing or do you have to start taking EP's apart? I already have the Baader Zoom so would I be better off getting other Hyperions and adding these rings to have a greater range of focal lengths.

Edited by simon84
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The thing with Hyperions is that they are quit BIG (and heavy)? They work better with (physically) bigger scopes and [iMO] wider "exit pupils". Used in 2" mode, I think they are a fine thing. Given (hopefully soon!) funding, I think I will retain e.g. my (8, 13, 17) mm Hyperions as "workhorse" eyepieces. I may look elsewhere for dedicted planetary OR (ONE) low power eyepiece.

For a smaller scope, I'd be tempted by Radians - or even TMBs. My onetime (now sold) GIGANTIC 30mm / 60 Deg (standard) Vixen Lanthanum was still like gazing into a "limpid pool" compared to the "OK, but..." experience with many other eyepieces I have owned... (even) Hyperions included. I think a 60 deg field is adequate in many cases? :)

P.S. I was never COMPLETELY convinced by the extension rings. A cool thing to play with, and sampler of the possibilities with other focal lengths... I sense the "extended" view is less than optimal though, and dismantling eyepieces in the field, ingress of dust (within the main e.p. structure) didn't overly rock my boat. ;)

Edited by Macavity
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If the view was not so good in one I'd try the other. If neither worked then I'd look at collimation or conditions. That's what I was trying to say.

Usually the Radian wins out observing, but the Hyperions are pretty close. If I wanted a picture however the Hyperions are easier to connect (threaded). I'd have to use a "Rail" connector for the Radians which is more cumbersome and not so accurate ;)

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I wouldnt be using the Hyperions to image as I've decided not to use my dslr for astro and am going down the ccd route so this if for purely visual reasons.

I was pretty much set on the Radians but the bigger fov of the Hyperions got me thinking and now that the tuning rings can be used for extra focal lengths you really do seem to get more bang for your buck with the Hyperions.

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If you're not doing imaging then it's really a compromise. Neither will disapoint, but you can either sacrifice a little fov for slightly crisper, or a little crispness for fov - but it's mostly unnoticeable. When you take the front lens set off the Hyperions they become erfl's if that helps. They are certainly more flexible with the FTR's. ;)

Edited by brantuk
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Erfl????????????? ;)

I don't think they'd be Erfl Kim - they must surely still be good? :)

I don't know what an Erfl is either and have never used Hyperions but use Radians and they are everything Kim and others say. Sharp, robust and with great contrast etc. I love them to bits.

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Yup Erfl's. I understand these to be laboratory grade eyepieces - so it's a positive thing lol. Here's a quote - link below for the full article:

"Each Hyperion eyepiece in the series is actually two eyepieces in one! Simply by unscrewing the forward 1.25-inch diameter portion of barrel that houses the negative achromat lens group, will provide a wide-field eyepiece of much longer focal length. Color correction remains excellent, and the field curvature that results is no greater than in a decent specimen of the 6-element Erfle design (and that’s what it is actually, when the negative achromat is removed)."

Baader Hyperion 8mm 1.25" / 2" Eyepiece | Telescope Accessories | Rother Valley Optics

Cheers

Kim

(I have a seperate 1.25" 20mm Erfl and it's a cracker ;)

Edited by brantuk
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Ah, with you now. Excellent link. So with 3 EP's I would have an absolute abundance of focal lengths to play with......

I think my mind is pretty much made up. Thanks for all the help Kim.

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I got a Radian earlier this year. I much prefer it to the LV 7 and 9mm I had before, and do not mind the smaller FOV for planetary work, even though I have a Meade 14mm UWA and a 22mm Nagler T4. For planetary work, I would settle for an ortho's AFOV, but their eye relief is a problem for me. If you want to use the EP for more extended objects, the Radian's FOV may be a bit tight.

Just my two cents

Cheers

Michael

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Hi Michael, the 60 degree fov of the Radians was the one thing that was putting me off.

I've just tried using Starry Night Pro using some different afov's to see but I need to work out what a 60 degree EP's afov is......I'm sure there is a guide here somewhere.

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I've had 3 Hyperions - 5mm, 8mm & 17mm and I wasn't that impressed with them to be honest. Yes they're 68 degrees but, unlike Radians, they aren't sharp to the edge (and I used them with some pretty slow scopes).

So in terms of usable FOV there isn't really much difference.

Hyperions also suffer from worse lateral colour than the Radians with a bright "Ring of fire" effect around the edge of the FOV when viewing bright objects.

But, in defence of the Hyperions, they were only around £68 new when I had mine - and so were pretty good value.

But at the current price, and with the "3 for 2" deal on Radians, there really is no contest.

Get the Radians - I would. (Heck, I just did!).

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I've spent some more time thinking about it today and seeing as I already have the Baader Zoom I think I'm going to get the Radians instead.......with a decent barlow or powermate thats 6 very decent focal lengths......so it looks like I'll be ordering the 18mm, 12mm and 8mm.......

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Just my 2 cents: I would get the 3 for 2 radian promotion and I would be done with it.

Why?

Do you really need that many FLs to play with? Specially knowing you have limited chances to observe and all the fiddling in the dark will make you loose precious time? Not to mention the risk in loosing a part of that expensive gear.

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I've spent some more time thinking about it today and seeing as I already have the Baader Zoom I think I'm going to get the Radians instead.......with a decent barlow or powermate thats 6 very decent focal lengths......so it looks like I'll be ordering the 18mm, 12mm and 8mm.......

you won't regret it.

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