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Best planetary eyepiece


trazor
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Hi all,

I have a 127 m/m Triplet refractor, focal lg. 954 m/m,

Which eyepiece/eyepieces would you good people suggest, for Good planetary visual use.

Good eye relief would be nice, not particular about wide field of view.

Will pay the price for the right eyepiece/eyepieces.

So many choices, can you narrow it down for me???

Thanks for reading.

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If you are using a manual mount I would look at delos or Pentax xw if a tracking mount then the orthoscopics will do best. The ortho's are cheaper and most planetary purists would say you should go for them anyway. But the delos and xw give a wider view and are nearly as good so in my opinion better for manual mounts.

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A friend of mine, swears by Vixen LV & NLV EPs as the only thing he likes since Orthos became impractical for him. The brief views I've had through them and his FLT 132 were certainly impressive, although I have to take his word for what's down to the EP and what's down to the scope. For my part as a non-glasses wearer, the eye relief was extremely comfortable and relaxed.

Russell

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Perhaps I'm being pedantic, but Pentax XWs are orthoscopic. They just aren't Abbe-Orthoscopic ;).

The XW's (and indeed Delos) are said to give performance equal to that of an ortho, perhaps only slightly bested by BGO / Hutech Orthos.

Oh, and the Nagler Zoom is brilliant :)

Edited by Naemeth
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I have a 120mm F/7.5 ED refractor so not far off the spec of yours. My high power set, chosen after trying many eyepieces over quite a few years :rolleyes2:, is:

Pentax XW 5mm = 180x

Tele Vue Radian 4mm = 225x

Pentax XW 3.5mm = 257x

Tele Vue Radian 3mm = 300x

All the above offer 20mm of eye relief and a 60 or 70 degree field of view. Having compared them carefully with a range of quality orthoscopics I'm confident that they give little or nothing away in terms of optical performance and provide a comfortable and relaxing high powered window into space :smiley:

I have owned a couple of Tele Vue Nagler zooms as well but, though they are undoubtedly excellent, I could never quite warm to them for some reason that I still can't fathom.

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There was a second-hand XW5 on ABS-UK a few days back. I swear by my XW7 and XW10 for planetary. By contrast I used to swear at my 5mm ortho (long-since sold), given its minute (non-existent) eye relief. Orthos are not EPs for those who want reasonable eye relief. The XF8.5 I have is also great on planets.

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Low end of Delos in my opinion. 3.5mm, 4.5mm ( 275x / 212x). These would give great views.

I couldn't agree more :smiley: I think Tolkien would have used the Delos instead of the ring if he had been aware of them :grin:

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I've still not used a Delos but the overwhelming feedback on here and other forums is so positive they are hardly a "risky purchase" :smiley:

You can pick up used Radian's for around £150 less than a new Delos though, and I reckon they are pretty darn good for that money :grin:

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Perhaps I'm being pedantic, but Pentax XWs are orthoscopic. They just aren't Abbe-Orthoscopic ;).

Are they? An orthoscopic eyepiece needs to be free from rectilinear distortion and angular magnification distortion, and should not show spherical aberration or coma down to F5. I think XW and Delos corrects for angular magnification distortion but not rectilinear distortion, so they are not 'orthoscopic', only 'orthoscopic like'.

EDIT: Whether they are orthoscopic or not have no relation to whether they are good for planets. XW and Delos are the best long eye relief planetary eyepiece money can buy.

Edited by E621Keith
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That's exactly what Delos is sold as as well, a planetary eyepiece. That's why they don't go longer than 17.3mm I guess, unlike many of the other ranges.

The Delos is a replacement for the Radian too I read. the fact that many of us use fast scopes so can actually use the longer Delos for mid range DSO viewing is a bonus, I'd expect they designed them for use in much longer focal lengths for the purpose of use as planetary eyepieces in larger SCTs. I'm quite happy to use the longer Delos in my fast larger dob though :D

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That's exactly what Delos is sold as as well, a planetary eyepiece. That's why they don't go longer than 17.3mm I guess, unlike many of the other ranges.

The Delos is a replacement for the Radian too I read. the fact that many of us use fast scopes so can actually use the longer Delos for mid range DSO viewing is a bonus, I'd expect they designed them for use in much longer focal lengths for the purpose of use as planetary eyepieces in larger SCTs. I'm quite happy to use the longer Delos in my fast larger dob though :D

This is Tele Vue's take on the Delos concept:

"Concept: It was natural to take lessons learned from the tremendously successful Ethos project and apply it going forward. In the fall of 2008, Paul Dellechiaie was tasked to investigate a long eye-relief eyepiece design in the 70° AFOV range, retaining the key performance goals met with Ethos...."

and:

"The Delos was conceived as a narrower field Ethos. Reducing the field to 72° allowed freedom to increase eye-relief, while controlling pupil aberrations, all without making the eyepiece too large. With Ethos performance standards as benchmarks, the Delos design achieves full field sharpness, virtually perfect f θ (theta) distortion mapping, and color neutrality. Image fidelity is maximized utilizing glass matched multicoatings and anti-reflection surfaces throughout the eyepiece."

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If good eye relief is desirable I think I'd be tempted to steer away from some of the orthos. You almost have to climb inside some of the shorter focal length BGOs. I think the BCOs are supposed to be a little better in that regard, but not enormously? I do very much like my BGOs, but I just don't think I'd recommend them in this instance.

James

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A very strong point about the Delos and the Radian made by John. How right he is much cheaper and so little in the actual performance if you ignore the FOV. As for this colour cast that I have read so much about, well you would think one was blue and the other red to listern to some people, for me it is nothing to even worry about.

I have the 4mm Radian as John and also the 3.5mm and 4.5mm Delos's, all I can say is if there was a 4mm Delos i would not buy one as an upgrade as good as they are. I also have the 5mm Radian but have not used it very much since the Pentax 5mm landed, that has the edge over the 5mm, but again not by much.

I think the Radian is a very under rated piece of equipment and at this level it is never going to be bad.

Alan

Edited by alan potts
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There is really not much in it. I haven't used XW. Do they have the adjustable eye guards like Delos? If not then get the Delos, optically they are basically identical everyone says and that feature on the Delos is top drawer.

The XW's top sections screw smoothly up and down and have around 15mm travel. The Delos has a smooth travel with a twist lock action I believe. The Radian's have a click stop action and about the same range of travel as the XW's.

The thing that always gets me with the XW's is how a design that has been on the market for around 10 years, is hardly ever advertised and was aparently designed for spotting scopes, can be so good for astronomy :smiley:

If Pentax really put their mind to the astro market you wonder what they could produce.

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