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Orion Expanse Re-visited


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I obtained my first Orion Expanse eyepiece in 2016. The 9mm is supposedly the best of the range so that was the one I initially purchased. I’m fairly certain these were originally manufactured (or at least distributed) by Barsta/BST. The series has been marketed under a variety of brand names. As far as I know they are all more or less the same apart from the branding and housing finishes. SvBony appear to have a similar line although I don’t know how or if they differ. There have been rumours that the T.S. Optics versions have better coatings, but I can’t substantiate this. There are four in this range of fairly lightweight 66° field eyepieces: 6mm, 9mm, 15mm and 20mm. The 6 and 9mm have Smyth-type barrel lenses while the 15mm and 20mm do not. My Orion 6 and 9mm have 22mm chromed brass barrels featuring an undercut. At 75mm the 6mm is 5mm taller than the 9mm eyepiece.

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Both have 20mm eye lenses with the 6mm having an 8mm field stop compared to a 15mm stop in the 9mm. Orion Telescopes & Binoculars claim around a 15mm eye relief for both the 6mm and 9mm Expanse. Which I think is a tad optimistic.

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I acquired the 6mm relatively recently. Although just over three years ago I bought a generic 15mm ‘UltraWide’ which is to all intents and purposes a 15mm Expanse.

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The UltraWide had a black aluminium flared barrel. My plan was to use it with a light ‘grab and go’ modified ST80 set-up. Unfortunately it exhibited a lot of lateral astigmatism at f/5 that could only be just about ameliorated with a Barlow.

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As it was primarily intended for rich field observing this wasn’t really an option. I wouldn’t particularly recommend the 15 and 20mm versions with anything less than an f/8 focal ratio. 

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One aspect that I did like about the 15mm was that there were no eye placement issues. The 9 and 6mm can noticeably ‘kidney bean’ if the eye position isn’t quite right. I never thought the 15mm was quite as sharp or as contrasted as the 9mm either. Eye placement issues aside, the 9mm is bright, very sharp across the field and well contrasted. Colour separation is excellent and it is just as good on planetary targets as open clusters. 

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It can have a tendency to ghost on particularly bright targets such as the Moon, especially if coupled with a Barlow. The 6mm Expanse is basically as good as the 9mm in my opinion. Although in my experience it can have a tendency to ghost slightly more than the 9mm version. Both Expanse eyepieces can suffer this fault primarily with lunar viewing, although having said that I have had pretty decent ghost-free views of the Moon with both of these eyepieces when used without a Barlow. 

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There are some interesting build differences between my new 6mm and older 9mm Expanse EP’s. They are only trivial but may be indicative of different manufacturers. The Barsta site appears to have disappeared from the internet so I have no idea if they still commission products. The Expanse roll-up rubber eyeguards look identical at first glance. However, the newer 6mm Expanse eyeguard consists of a softer rubber reminiscent of the old GSO roll-up guards. These are distinctly different in feel to the eyeguard on the 9mm Barsta made Expanse.

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The older 9mm eyepiece has a typical Barsta/BST stiffer guard. The end caps on the 6mm are not traditionally like Orion dust caps. The embossed ‘Orion’ logo isn’t present on the 6mm and the field lens dust cap doesn’t have the number ‘317’ on it like most of my other Orion eyepieces. Although this may be due to present day supply problems. The distinct coloured band or collar at the top of the housing of each eyepiece are slightly different hues of blue. 

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At the end of the day these eyepieces are quite reasonably priced for the performance they deliver. Compared to a lot of more modern offerings they are possibly a little antiquated. The two shortest focal lengths have some eye placement issues and the 15 and 20mm will show lateral astigmatism in faster focal ratio scopes. The advantages with these eyepieces are that they are light and relatively small with a capacious 66° field of view. I particularly like the 6 and 9mm for deep sky with grab and go set-ups. Primarily because they are relatively compact and easily carried in a pocket. Recently there have been changes at Orion Telescopes & Binoculars and they have closed their warehouse facility in the Netherlands. Whether these particular eyepieces will continue to be available is not known. 

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  • 2 weeks later...

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SvBony have a version. They claim a 68° AFOV (naturally).

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SvBony also claim seven lenses in five groups.

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It's a possibility it has been redesigned, although I doubt it.  

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FWIW I thought the eye placement was slightly better than with the Orion. Although it's probably my imagination.

Edited by Zeta Reticulan
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I have the Svbony 6mm and it gives surprisingly good views. I've now replaced it with a Baader Morpheus 6.5mm, which is vastly better, of course, given the difference in price. The key for me is the FOV (76° in the Morph), which reduces frequent nudging of my dob at high mags.

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5 minutes ago, cajen2 said:

I have the Svbony 6mm and it gives surprisingly good views. I've now replaced it with a Baader Morpheus 6.5mm, which is vastly better, of course, given the difference in price. The key for me is the FOV (76° in the Morph), which reduces frequent nudging of my dob at high mags.

I looked at that Morpheus but it's a tad heavy for my 60 EDF and it isn't exactly 6mm. 

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14 minutes ago, cajen2 said:

Yes, Baader seem to like their half mm for some reason - 4.5, 6.5, 12.5 and 17.5. It makes no odds to me. I also have a couple of Pentax XWs but the Morpheus are my favourite...

I bought the 14mm Morpheus some years ago (when they were cheaper lol) and it's one of my favourite EP's.

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As the 'Titchy Sixty' 60mm Altair doublet is, well, titchy, I only take a couple of EP's out with it. One is a 19mm Panoptic and a 2x Barlow. This gives 3mm and 1.5mm exit pupils. The other is 6mm, so with the Barlow 1mm and 0.5mm exit pupils. If they made a 6mm Panoptic I'd be really happy lol. A 6mm Delos is way too heavy.

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1 hour ago, cajen2 said:

Yes, Baader seem to like their half mm for some reason - 4.5, 6.5, 12.5 and 17.5. It makes no odds to me. I also have a couple of Pentax XWs but the Morpheus are my favourite...

Its a German thing..... They want to confuse you lol. 

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16 minutes ago, orion25 said:

Great review, as always, Zeta. I have the complete Expanse set that I use almost exclusively with my 127mm and 180mm Maks. The 9mm and 15mm are probably my favorites. How are things on your planet ;) ?

Thanks Reggie. I think I've used mine with my Mak's. They are remarkably sharp with excellent colour separation. I compared them to ortho's and Plossls and they easily hold their own. Things are pretty cool at my end. I've had some great August sessions. In fact I've had over a hundred sessions before September. Clear skies!

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How did you get on with the NPL comparison? I'd have thought the eye relief would be a bit tight on an 8mil, though the longer f/ls are excellent for the price. I have a 30mm which is so good, for a cheap EP.

 

Edited by cajen2
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1 hour ago, cajen2 said:

How did you get on with the NPL comparison? I'd have thought the eye relief would be a bit tight on an 8mil, though the longer f/ls are excellent for the price. I have a 30mm which is so good, for a cheap EP.

 

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The 30mm NPL is my favourite 30mm (or thereabouts) Plossl. It just feels right ergonomically compared to my other 32mm Plossls (including the 32mm TV Plossl). I'm not sure of the 8mm's actual eye relief distance. I can tell you it is identical to the 8mm SvBony though. As far as I can tell the NPL and SvB 8mm are practically identical. 

Edited by Zeta Reticulan
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5 minutes ago, Zeta Reticulan said:

Maybe things are changing on Planet Baader.

Maybe so.  I would actually like to see this 14mm everyone keeps mentioning as being so good.  I knownthe variable is a pretty solid piece of glass 

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Just now, Mike Q said:

Maybe so.  I would actually like to see this 14mm everyone keeps mentioning as being so good.  I knownthe variable is a pretty solid piece of glass 

I don't know which focal length is considered the best of the range. When I bought my 14mm the 17.5mm Morpheus was still a rumour. 

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15 minutes ago, Zeta Reticulan said:

I don't know which focal length is considered the best of the range. When I bought my 14mm the 17.5mm Morpheus was still a rumour. 

I have a 14mm and 20mm 2 inch eyepiece that i really like.  I would be hard pressed to drop to a 1.25 inch and give up the light gained by them.  Amazing views. 

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Mike's 2" EPs are the Orion branded version of what's sold here as StellaLyra  (Long Perng) 80° LER/UWA. I have the 20mm and it's superb.

The best Morpheus is said to be the 17.5mil. I can't confirm this as I'm already sorted for that f/l, but I can say my 12.5, 9 and 6.5 are excellent.

Edited by cajen2
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