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31mm Celestron Luminos eyepiece, one of worst I've used

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#1 RichA

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Posted 29 August 2015 - 04:20 PM

Very heavy, which I could live with if it was a good performer.  Impossible to see the edge of the field and not induce kidney bean.  Using it was a trial.  Mediocre edge quality, relative to even simple, uncorrected designs like Plossls.  Uneven brightness across the field.  The one bright spot was the centre was very sharp and contrasty.  Very good build-quality.  Far better than the crude black anodizing seen on some other eyepieces.  But I wish they'd spent some of the money on the optics and optical design. 


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#2 CHASLX200

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Posted 29 August 2015 - 04:36 PM

Lots of cheaper stuff out today i won't touch.

 I am a Televue lover till death.

 

Chas


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#3 cam1936

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Posted 29 August 2015 - 10:20 PM

I have the 10mm Luminos. Like you said it does have excellent build quality. The 10mm does not sound as bad as your 31mm in regards to eye position, but it is not overly easy either. Sever ghosting when a bight object is near the edge of the field. Not bad on axis and not too bad off axis on dim objects, but it's no TV either.

You get what you pay for. Too bad they didn't put a little more into the design even at a little higher price point.

#4 RichA

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Posted 29 August 2015 - 11:04 PM

I have the 10mm Luminos. Like you said it does have excellent build quality. The 10mm does not sound as bad as your 31mm in regards to eye position, but it is not overly easy either. Sever ghosting when a bight object is near the edge of the field. Not bad on axis and not too bad off axis on dim objects, but it's no TV either.

You get what you pay for. Too bad they didn't put a little more into the design even at a little higher price point.

The 10mm probably stresses the design type less than the 31mm.  I think that there is a barrier to function that price still dictates, despite China production.   The Luminos was only $240 so it (IMO) wasn't enough to pay for a good design.


Edited by RichA, 29 August 2015 - 11:05 PM.


#5 RichA

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Posted 29 August 2015 - 11:06 PM

Lots of cheaper stuff out today i won't touch.

 I am a Televue lover till death.

 

Chas

A friend is the same way, not a bad philosophy!



#6 stargazer193857

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Posted 30 August 2015 - 12:07 AM

Over a year ago when I asked what a good bang for buck eyepiece is, and someone recommended a GSO Plossl, someone else replied that a Luminos is not that clear. I now know they are 82*.

 

 

From what I can tell, a Luminos is the low price leader for 82* negative field lens eyepieces. Just how bad are they around 5-6mm?

 

I don't mind out of view glare helping me find a planet. I only care how clear something looks if it is in view.

 

Right now I'm thinking of a Meade 5.5mm.



#7 paradise

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Posted 30 August 2015 - 06:02 AM

Like I said several times here, I've got the 23mm Luminos 2", it was not very good on a f/5 reflector, it was sold for an ES 24mm 82° much better in all points, and less expansive in Europe.

 

The Luminos are made for SC scopes, it is true, but I did not find good transparency, good sharpness, nothing good in fact... :(


Edited by paradise, 30 August 2015 - 08:09 AM.


#8 russell23

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Posted 30 August 2015 - 07:18 AM

Very heavy, which I could live with if it was a good performer.  Impossible to see the edge of the field and not induce kidney bean.  Using it was a trial.  Mediocre edge quality, relative to even simple, uncorrected designs like Plossls.  Uneven brightness across the field.  The one bright spot was the centre was very sharp and contrasty.  Very good build-quality.  Far better than the crude black anodizing seen on some other eyepieces.  But I wish they'd spent some of the money on the optics and optical design. 

 

Ahh ... reminds me of the good ol' ... errr ... the handful of days when I endured the disappointment that was the 19mm Luminos.

 

Dave



#9 Mitrovarr

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Posted 30 August 2015 - 10:18 AM

I've heard too much criticism of the Luminos to consider them anymore. The Meade MWA series is the same way. If so many people dislike it so much... it must be doing something pretty wrong. Especially at the Luminos' low price point - people would be willing to cut it a lot of slack. I guess some people like them, but even then they'll usually qualify it.

 

As far as cheap 82 deg. eyepieces go, I think it's much better to go up to the next tier and get a Meade UWA or ES 82. I have a Meade UWA (the 20mm) and I like it a lot. I think the main advantage with the ES series is that you don't get that stupid twist-up eyecup.


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#10 russell23

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Posted 30 August 2015 - 12:44 PM

I've heard too much criticism of the Luminos to consider them anymore. The Meade MWA series is the same way. If so many people dislike it so much... it must be doing something pretty wrong. Especially at the Luminos' low price point - people would be willing to cut it a lot of slack. I guess some people like them, but even then they'll usually qualify it.

 

As far as cheap 82 deg. eyepieces go, I think it's much better to go up to the next tier and get a Meade UWA or ES 82. I have a Meade UWA (the 20mm) and I like it a lot. I think the main advantage with the ES series is that you don't get that stupid twist-up eyecup.

 

The Luminos seem to get better reviews of the 1.25" focal lengths.  But I agree with you - the ES82's and Meade UWA are very good.   I think the 5.5mm Meade UWA is one of the gems out there on the market.   For $129 new it is a real steal.   I also like the 20mm Meade UWA a lot optically.  The biggest drawback I found to that one was the large top diameter surface.  

 

Dave


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#11 Ernest_SPB

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Posted 31 August 2015 - 01:34 PM

Very heavy, which I could live with if it was a good performer.  Impossible to see the edge of the field and not induce kidney bean.  Using it was a trial.  Mediocre edge quality, relative to even simple, uncorrected designs like Plossls.  Uneven brightness across the field.  The one bright spot was the centre was very sharp and contrasty.  Very good build-quality.  Far better than the crude black anodizing seen on some other eyepieces.  But I wish they'd spent some of the money on the optics and optical design. 

What you described looks like normal and known effects of Narger type-5 family eyepiece daylight usage. 


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#12 thomasr

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Posted 31 August 2015 - 03:37 PM

I really am starting to think that Celestron purpose-built the Luminos line for use in SCTs, and the rest of the optical world be ****. My 15mm is a solid performer in my C6: no eofb that I can detect, objects are sharp from centre to edge, and contrast seems good when I'm trying to find DSOs. My 7mm is good too but suffers from shorter eye relief, and a bit more difficulty (for me at least) bringing things to focus.

Bashing the Luminos line seems to be a bit of a national sport on CN, but I'm happy with mine. The 15mm gets more use than any of my other EPs.
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#13 deefree49

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Posted 31 August 2015 - 09:59 PM

Thomasr - I have to agree with you. I have 3 Luminos EPs and can find no major fault with any of them. Maybe they are built with the longer f/l SCT scopes in mind?

 

I also find the 15mm to be a valuable member of my EP collection. I haven't used the 10mm much mostly because the weather and sky around Ohio this summer has been pitiful.

 

The 31mm, one that has received more than its share of negative reviews around here actually gave me a very impressive view of Jupiter and a moon transit. Maybe it was that I was only looking at the center of the field but it was very sharp and clear. I was able to see Ganymede in transit even though it was only at about 75x with my C 9.25". At first I thought it was a shadow but it was the actual moon going across the disc.

 

I'm sure it pales compared to Televue but for the money I've been quite satisfied with them. The 31mm is a giant though, very heavy and fat in the middle. My 40mm EP is much lighter though it is only a 68* so I suppose that isn't a completely fair comparison.


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#14 Lew Zealand

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Posted 31 August 2015 - 10:24 PM

This just makes me sad as my 31mm Celestron Axiom is a very good EP, with many of these problems reduced if not absent.  I bought it for it's performance at f/6 and it's a keeper.  I don't use it as often as my 34mm Meade 5K SWA due to its mass but it gets it's focuser time.

 

I wish I knew the story about why the Ax was replaced by the Luminos but I assume it's politics and suppliers.  Same as it ever was…


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#15 BigC

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Posted 08 July 2018 - 03:54 PM

Bucking the critics here and finally getting the 31mm to COMPLETE the Luminos set at "Foggy Valley Observatory" (just made that name up but it fits!). The edge of field brightness  and kidney beaning don't seem much of an issue to my aphakic(1960 cataract surgery therefore no implants)  eyes. Probably something to due with the focus point being rather different from the overwhelming majority.I often require an  extension to reach focus without glasses;and with glasses only the largest eyepieces can deliver the full FOV.

 

I also find the original Orion ED-2 and Celestron X-Cel  both quite satisfactory.


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#16 MrJones

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Posted 09 July 2018 - 01:57 PM

Congratulations? smile.gif

 

I still have my decloaked one and the camera hood as eyecup works well and helps with the blackout related to long eye relief.

 

In the past I've found the ES 68 34mm more user friendly but you've inspired me to give it another go!

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#17 aggiechick

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Posted 09 July 2018 - 03:31 PM

I just got in three of the Luminos yesterday to use with my Orion XT8i, f6. I've been contemplating just sending them back without using them and spending more for the ES equivalents, but now BigC has me curious. Most of the negative posts I've been reading are from 2015 and prior; maybe Celestron fixed some of the issues.

 

If I have clear skies tonight, I may check out the Luminos I received. I got a 31mm and a 26mm to replace Orion Q70 26mm and 38mm that I got with the scope. (The 38mm Q70 doesn't fit into my 2" barlow nor into my scope... known issue for some Orion Q70 38mm EPs.) I also got a 10mm and a 15mm to replace some Orion Plossl EPs and was planning to barlow them to get down to 5mm when I needed greater magnification.

 

I'm also not sure about keeping the 31mm and the 23mm because of their size. It will be interesting to see if my XT8i can stay in place with those grenades, and I don't know how I'm going to hook up my iPhone to the large diameter EPs to snap some pics.


Edited by aggiechick, 09 July 2018 - 03:31 PM.

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#18 naramsin

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Posted 09 July 2018 - 04:10 PM

I have the 23mm and two of the 7mm Luminos and I like them a lot. I liked them more when I deshrouded/uncloaked them. Each lost several ounces in wt. You can search the forums and google images for an idea of what is involved. The process is sort of reversible--the hard part is pealing off the little aluminum stickers without damaging them.

 

One thing you lose besides wt. are the mostly nice telescoping eyeguards. But I found over time I don't miss them. And I glued some O-rings on the 23mm for when I use glasses. The naked 7mms work really nicely in a cheap Orion binoviewer.

 

I also have the Meade UWAs, some of which are superior (the 5.5mm and 8.8mm are amazing, the 20mm less so). I got the 20mm after the 23mm because it was insanely cheap (~$20) from Amazon. I uncloaked it and the 5.5mms as well (this was a messier process than for the Luminos). For some reason the 23mm is just a 'better fit' for me (not exactly a scientific assessment). grin.gif But the 20mm is not bad on my 8" Newt, so I'm keeping it around for now.


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#19 tonyt

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Posted 09 July 2018 - 04:41 PM

When I compared 23mm eyepieces years ago, the Luminos had edge of field brightening and much worse edge correction than the Axiom. They would have needed a serious overhaul to correct the problems.


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#20 naramsin

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Posted 09 July 2018 - 05:22 PM

When I compared 23mm eyepieces years ago, the Luminos had edge of field brightening and much worse edge correction than the Axiom. They would have needed a serious overhaul to correct the problems.

 

I've heard this a lot, but I haven't seen it myself. It may be sample variation, which, if true, would be a good reason not to buy it unless one wanted to spend time trying several samples and sending the bad ones back. The bigger factor is probably the scope it's used with. I mostly use it with a 102mm Apex and a recently acquired 6" Newt, but it works fine in my 8" f5 too (with coma corrector). As I mentioned in another post recently, the 23mm has angular magnification distortion (AMD), which is apparently what many lens designers avoid in telescope eyepieces. But after many years of photography with a variety of wide-angle lenses, the thing that drives me batty is rectilinear distortion (RD). A panoptic, for example, would probably make me sick, it has such an insane amount of RD. So I'm happy with the edge sharpness of the 23mm. By this I mean the stars are pinpoints at the edge. I guess I'm just lucky.

 

My two 7mms (an eyepiece that doesn't get reviewed as much) also performs well. They're nice on Dobsons (or manual GEMs, as I tend to use), with that huge 82* view and decent sharpness at the edges.

 

That said, for planets I prefer orthos. 



#21 Miranda2525

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Posted 09 July 2018 - 06:34 PM

Some people Just can't see certain problems with eyepieces, while others do. I think it is chalked up to experience and how many hundreds of eyepieces used in different telescopes with different focal lengths people have used to critically evaluate them in different observing conditions.

 

I don't think it is "sample variation" in the Luminos eyepieces. Many have seen the EOFB, and the excessive eye relief in the 31mm that makes it a not-so-good eyepiece.

 

I have witnessed it myself.

 

However, I have read that some of the shorter focal length ones are better.


Edited by Miranda2525, 09 July 2018 - 06:35 PM.

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#22 naramsin

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Posted 09 July 2018 - 10:23 PM

I do notice things, sometimes. Tonight I grabbed the 23mm Luminos in the dark for one last look at Jupiter, M13, and M27. When I moved Jupiter to the edge of the view, it didn't have the familiar football shape (AMD). That's funny, I thought. Until it dawned on me that I'd grabbed the 20mm Meade by mistake! foreheadslap.gif The deshrouded 23mm and 20mm are about the same size and shape.grin.gif But it was interesting to see the result of what must be a major design decision for these wide-angle EPs. The Meade seems to have very little AMD. Again, the 20mm is nice, but there's just something about that 23mm....

 

I don't doubt that some people see EOFB, ring of fire, etc. with these EPs. Perhaps eyeball shape and brain science come into play....



#23 MrJones

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Posted 10 July 2018 - 08:06 AM

I had the 31mm Luminos in my 4" f/7 last night for 15 minutes because that's all I could take. I'd forgotten how bad it is. Or maybe it was not quite as bad in a SCT. While EOFB and blackout are problems the main one is the kidney beaning and related glare. I could get about half the field in view before the kidney beaning started, then to see the edges I had to peer around all the kidneys. Maybe they forgot to make 1 or 2 of the elements with ED glass? It was a relief to put my not perfect but far better ES 68 34mm in afterwards. I don't like selling equipment this bad so I'll probably throw it away.


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#24 naramsin

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Posted 10 July 2018 - 08:39 AM

I had the 31mm Luminos in my 4" f/7 last night for 15 minutes because that's all I could take. I'd forgotten how bad it is. Or maybe it was not quite as bad in a SCT. While EOFB and blackout are problems the main one is the kidney beaning and related glare. I could get about half the field in view before the kidney beaning started, then to see the edges I had to peer around all the kidneys. Maybe they forgot to make 1 or 2 of the elements with ED glass? It was a relief to put my not perfect but far better ES 68 34mm in afterwards. I don't like selling equipment this bad so I'll probably throw it away.

 

That's interesting--I'll have to try the 31mm sometime if I can find one at a local astronomy club. I wonder if deshrouding it would help? It would certainly make it lighter (but not as light as my GSO 30mm SV). There have been so many complaints of recent (i.e. past decade) Celestron EPs that I believe you--some are probably just design duds, others (the X-Cels, I believe) apparently come new from the factory plagued with dust and other QC issues. My new Omni Plossls, like my Luminos, are fine, however.



#25 BigC

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Posted 10 July 2018 - 08:40 AM

Mr. Jones
You can send the despised 31mm Luminos to me instead of throwing it away. I'll even pay postage! Will pledge not to resell or even give it away if that helps.
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