Excelsis - Display Vote

Orion Expanse Wide-Field 6mm

Like in my review of the Expanse 9mm, I wanted to replace my venerable 6mm UO ortho with something with longer eye relief. I didn't think the Expanse would be good enough, so I did a side-by-side comparison with the 6mm Vixen LV and 6mm UO ortho.

Surprisingly, the Expanse has held its own quite admirably on deep sky and planets. It's images were nearly as bright as the ortho and brighter than the Vixen. It was sharp over just about 80% of the field - but this is actually a wider usable field than in the 45 degree FOV's of the the ortho and LV. Eye relief is generous, though not as long as the LV, but eye placement was trickier. As with the 9mm, its contrast was not as good as either the ortho or the Vixen.

What did this mean in practical terms? The Expanse did well on deep sky, particularly nebula like the Swan, Dumbell and Ring and also did well on globulars and open clusters. Contrast and sharpness was not as good as the LV, but the images were significantly brighter and the FOV much wider. The wider FOV and brighter image nearly equalled the LV.

The Expanse's on-axis planetary performance was also quite good. Both the ortho and the LV are supposed to be much better planetary eyepieces, but the Expanse wasn't far behind them. The Expanse equaled the ortho in brightness and beat it in eye relief, making it easier to catch those moments when seeing cleared. It's images were brighter than the LV with similar eye relief. The only drawback was a little off-axis ghosting. In the end, the Expanse's brightness and comfortable eye relief meant that I could see equal detail on Jupiter and Mars, even though it had a little less contrast.

Now the big knock - on the Moon, the 6mm Expanse falls apart. Ghosting was so severe (much worse than in the 9mm Expanse) that it was completely useless for lunar observing. If this is your only high power eyepiece and you want to look at the Moon, forget it.

Bottom line - I was planning to keep the 6mm and 9mm LV's, but I'm going to hang onto the Expanses into the fall to test them on Jupiter and Saturn. Until then, at $49 new and $40 used, the Expanse is a bargain unless you frequently look at the Moon. Again, if lunar observing is one of your favorites, skip the Expanse line.

Overall Rating: 7
Optics:7 Value:8
Weight: 6 (Veritable Vote)
Date: 07/21/2003 01:29:16 am PST
By: PJBilotta
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=258110

How do the Expanse EPs perform in fast scopes?  I have an 8&quot; f5 scope.  My daughter's scope is a short tube 4.5&quot; scope (f4.4).

Thanks.

Jeff Roseberry

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