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Planetary EP 7mm


IB20
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Hi, 

Sorry for another planetary EP thread! 😁

As I lurch towards being a full on planetary observer I'm trying to identify an excellent 7mm planetary EP, probably leaning towards an ortho but open to other suggestions.

I can only seem to find:

7mm Japanese HD Orthoscopic EP - Fujiyama

7.5mm Tak LE HD

7mm BGO (not available but does anyone want to sell me theirs?)

7mm Ohi Optical Genuine Abbe Orthoscopic EP 

Then there are the widerfield EPs which would probably also give me excellent views:

7mm Pentax XW

7mm TV Delite

 

Does anyone have any recommendations from these or suggestions of other EPs that might suit?

Ta!

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Before spending big bucks on a single 7mm eyepiece for cyclops viewing, consider spending a similar amount for entry level binoviewers and a pair of 15mm to 20mm plossls or simple wide fields.  Put a 2x Barlow or just the optics element ahead of the binoviewer to reach focus in most scopes, and you should be at about 3x.  This yields somewhere between 5mm and 7mm effective focal length for those low cost eyepieces.  I find I get much better views with two eyes and simple eyepieces than with one eye on the planets, and I've compared using XWs, Delos, and Morpheus eyepieces.

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Everything as stated in the above responses. The 7mm XW would be my choice for mono viewing, but the binoviewer, barlow and plossl or orthoscopic option will leave even the best mono eyepiece standing. The XW's are excellent planetary eyepiece though.

Edited by mikeDnight
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Lots of love for the Pentax XW, I shall look into them. I might explore binoviewers in the future but my current set-up wouldn't support the weight so am only looking for monoviewing right now. 

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What about the Morpheus 6.5mm?

I've not used that focal length, but have the 9mm and 17.5mm and both are excellent, I would expect the 6.5mm to be no different. The Pentax 7mm is a lovely eyepiece too, I've owned and liked it very much.

I do agree with Mike though..on the Moon and major planets, any well collimated binoviewer with a half decent pair of eyepieces will outperform every top end solo eyepiece I've ever used.

I had a short session earlier this evening (due to mist and low cloud rolling in), and in hazy but steady skies I had superb views of Jupiter in moments of good seeing, (6 belts/bands, and I split the double double Epsilon Lyrae at just 61x..all with a Revelation/Seben binoviewer and a pair of Kson 16.8mm eyepieces at native focal length. Using a single eyepiece I have never been able to do this at less than 80x plus!

Dave

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1 hour ago, IB20 said:

Hmmm, seeing the Pentax 7mm is about the same size as a tin of beans and weighs nearly 400g might rule it out. What a beast.

 

The 7mm XW isn't a big eyepiece and could easily be used in a small refractor or reflector without pausing a problem. If however you'd like a lighter eyepiece, you might consider the Baader Morpheus. These are superb and lightweight, although they still sport a beautiful large eye lens that's so comfortable to use. They barlow beautifully too! 

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I do like my 17.5 Morpheus, very comfortable to use and Barlows really well. Just checking the technical specs and it weighs 305g so not much lighter than the 7mm XW. 

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I've got the 6mm Fujiyama ortho and it's a superb eyepiece - razor sharp and distortion-free with loads of contrast so I'd expect the 7mm to be a great planetary eyepiece as well. Orthos are also very small and light but the small eye lens, short eye relief and narrow AFOV aren't for everyone and can take a bit of getting used to, but if you're using a tracking mount then that last issue is far less of a problem.

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Try a SVBONY 68° Ultra Wide Angle 20mm with a decent 3x Barlow to get ~7mm effectively.  It's wide field, great eye relief, and quite sharp in such a slow light cone.  I just completed a pair for binoviewing at 3x with a Meade 140 2x Barlow nosepiece and briefly wrote it up below:

It certainly wouldn't cost much to try out the combination.

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10 hours ago, F15Rules said:

I had a short session earlier this evening (due to mist and low cloud rolling in), and in hazy but steady skies I had superb views of Jupiter in moments of good seeing, (6 belts/bands, and I split the double double Epsilon Lyrae at just 61x..all with a Revelation/Seben binoviewer and a pair of Kson 16.8mm eyepieces at native focal length. Using a single eyepiece I have never been able to do this at less than 80x plus!

Dave

I’ve split Epsilon lyrae at 61.5x in monoview!😃

I am interested in binoviewers at some point, probably if (when) I get a 4” frac and more sturdy tripod/mount set-up.

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45 minutes ago, Mr Spock said:

I see you are looking for an ortho. Excellent choice - my 7mm Circle-T is my most used planetary eyepiece.

Is that T for Tani, Japan? Any idea how often something like that appears on the used market?

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Only occasionally. It's taken me over a year to get a 4mm - still missing a 6mm and 5mm.

Interestingly, a few months ago ENS had two 7mms for sale, plus a 9mm. All gone now though.

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Posted (edited)

Thanks, I’m in no rush and am happy enough to wait for a good ortho to appear. Nothing stopping me getting a nice wide field too. 😀

Edited by IB20
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13 hours ago, IB20 said:

I’m surprised no one has mentioned the Tak LE 7.5mm? Wonder why, are they a little over-priced for what they are?

The Tak LE's are really nice but some suffer from ghosting issues. My 5mm LE had the problem where the Moon was stunning, but as it drifted out of the field, there was a strong ghost image of the Moon still visible. My main gripe was that the image of the Moon and the ghost image had an overlap of around a third of the field of view. An alternative would be a secondhand Orion Ultrascopic or Parks Gold. These are beautiful eyepieces nolonger in production but can still be found secondhand. Vixen LV's and LVW's are special too, but are also nolonger in production. Baader Hyperion are worth taking a look at, as would be a longer focal length Orthoscopic combined with a barlow lens which will give you better eye relief. 

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16 minutes ago, mikeDnight said:

Vixen LV's and LVW's are special too, but are also nolonger in production.

Good point that the 7mm LV was discontinued in the NLV and SLV lines.  I believe the LVW had an 8mm rather than a 7mm.

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48 minutes ago, mikeDnight said:

An alternative would be a secondhand Orion Ultrascopic. These are beautiful eyepieces nolonger in production but can still be found secondhand. 

Funny you should mention this, I have been offered one. I think I might take a punt on it.

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I have the 7mm Pentax XW. As others have said, it’s really not a prohibitively big eyepiece - size and weight are not an issue in any of my scopes. Physical and optical quality are absolutely superb. I also had the 6.5 mm Morpheus for a while.  I found it to be pleasingly sharp and easy to use. There is so much ‘Morphoria’ going on these days that one hesitates to cast any aspersions in that direction, but, good as it was, I’d certainly put it second to the Pentax. 

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On 09/10/2021 at 13:55, mikeDnight said:

An alternative would be a secondhand Orion Ultrascopic or Parks Gold. These are beautiful eyepieces nolonger in production but can still be found secondhand. 

Thank you for recommending this, I’ve been using it tonight in some pretty ordinary seeing but I’ve been able to observe the GRS, Io’s shadow, multiple bands and a NEB barge in my little 80mm Starbase. Works beautifully on the moon too, chuffed to bits.

It’s an excellent EP, think I’ve landed a bargain!

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1 hour ago, IB20 said:

Thank you for recommending this, I’ve been using it tonight in some pretty ordinary seeing but I’ve been able to observe the GRS, Io’s shadow, multiple bands and a NEB barge in my little 80mm Starbase. Works beautifully on the moon too, chuffed to bits.

It’s an excellent EP, think I’ve landed a bargain!

You'll need to be careful you don't find yourself collecting the entire range. They can be quite addictive. I've got most of the range from 35mm down to 5mm, although they aren't all Ultrascopic's. Some are Celestron Ultima's, Parks Gold, and Baader Eudiascopic. They are all pseudo Masuyama's, a design based on the Zeiss astroplanar. Sadly, none of the above are currently in production, although they do appear second hand quite regularly. The largest I own, the 35mm, is lightweight and offers a low power field that appears to jump out of the eyepiece  as if suspended before the eye; quite a special effect not shared by many eyepieces. 

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