Wider, better, but . . . looking through the new Hyperion Zoom

Bottom line; Testing three zoom eyepieces this morning, it was obvious that if you pay more, you get more – but as is frequently the case with optical quality, what you get isn’t that much more and what you pay is.

(If that image looks familiar it's because I took a preliminary look at these three here. )

The three 8-24mm zooms I was looking through this morning were a Celestron ($63 new), a Vixen ($120 used), and a Baader planetarium Hyperion, ($180 used.) Actually the new price on the Vixen and the Hyperion are roughly the same, but I have seen the Vixen for much less. Prices quoted are what I paid.

Quality rating – sucked out of my thumb - I would give the Hyperion the edge, but I would be hard pressed to tell the difference between it and the Vixen. Maybe I just want it to be better because I paid more. ;-) The Celestron falls off a bit in quality, especially in terms of edge of field sharpness, but nothing I couldn’t live with, especially if I were on a budget.

What really gives the Hyperion the edge is the larger FOV at both low and high power. It seems to come close to its claims of a 50 degree fov at low power and a 68 degree fov at high power. I didn’t do any measurements, but I did practical tests under the stars.

My test instrument was an 80mm, F7.5 Orion 80ED, mounted on a binocular parallelogram mount and used straight through – no diagonal. (This is my intended major use for the Hyperion and why the extra fov means something to me. )

Click to enlarge image.

I tested the FOV on one of my favorite asterisms, the Coathanger. Plain and simple, it fit in all three zooms at the lowest power, but the you strained to fit it in the Celestron and Vixen, whereas it fit comfortably with plenty of breathing room in the Hyperion. This pretty much matches the simulation I see in Starry Nights when I pump in the specifications for the eyepieces. (See above image. Celesteron and Vixen about thesame, so I used just Celestron.)

I did a similar test with the Double Double in Lyre and Vega. With the Hyperion I could just fit both in the low power FOV – well, a little room left over, but not much. In the Celestron and Vixen they couldn’t quite fit – you get Vega, but not the Double Double. That’s also a good example of why I want the wider field – finding things. Anyone can get Vega in view. As you search for the Double Double – a little tricky simply because of the orientation of the scope and flipped image – it’s nice to be able to simply put Vega at the edge of the fov and circle around it until you stumble on the Double Double.

BTW – I can not split it with the 8mm setting – shows some elongation, but no clean split. One of these nights the air wll be still enough, however, where that may be possible.

OK – last category – mechanics. The Hyperion is hand grenade. It's roughly the same height as the others, but about 55mm wide vs 40 mm wide. Unlike the other two it has click stops for the major setting at 24, 20, 16, 12, and 8. That would, in theory, make it useful for binoviewing. But I have my doubts because it is so wide. The person I bought it from was selling a pair because he had bought them for binoviewing, but when he loaded them in the binoviewer he found his nose didn’t fit between them! No kidding. (I have heard other people with the same complaint with other eyepieces they've tried to use for binoviewing. )

What I found interesting was the different distance between each click stop. From 24 to 20mm, it’s a long, long twist. I measured ut to be about 30 mm. From 12 to 8 mm you hardly twist it at all! (about 5 mm.) This is not so on the Vixen and Celestron, though they do not have click stops and the sizes shown onthe barrell may or may bot be an accurate representation. The differences aren’t exactly the same, but there’s no dramatic change. But this shows obviously as you start to zoom. With the Hyperion nothing much seems to happen at first, then things start to happen faster and faster.

With all of the zooms you also have the counter-intuitive business of the FOV getting wider as the power is increased. Ok - it isn't really getting wider - that is a higher power isn't wider than alower power - but it does get proportionately wider since the apparent fov moves from 40 to 60 in one case and from 50 to 68 in the case of the Hyperion. Doesn't bother me - what you see is what you see - but it may bother people who are really wrapped up in the numbers.

As soon as you know it’s there, who cares? And I’m not sure why we care about the click stops at all. I mean, zoom in until you are satisfied with the view, then stop. Framing an astronomical object is similar to framing a work of art or any other scene and no numbers make things fit better. I find them an interesting curiosity, however, and I guess I would find them useful if I were using the zoom simply as a test eyepiece to help me know which size fixed eyepiece I wanted to use. Then, of course, I have observed with people who just absolutely have to know what power they're using. I seldom give it much thught. What works, works - and on any given night with any given observer and with any given eyepiece and telescope what works is going to vary. (OK - some dya I may want to say I could see detail at such and such a power, but couldn't see it at a lower power - maybe ;-)

Aside from that, the mechanical operation of both the Hyperion and the Vixen are delightfully smooth. The Celestron, as I’ve mentioned before, feels a bit gritty, but this roughness doesn’t seem to adversely impact performance.

Can you find happiness with the Celestron? If they’re all like the one I have, I would say yes – especially if you’re on a budget, or you simply want to use the zoom casually – or maybe try a zoom for the first time. If money isn’t a significant issue, go for the Hyperion, especially if the wider field is critical to you, such as being used on a scope without clock drive or goto capability. Found a good used price for a Vixen (I saw one go recently for $90 on AstroMart), grab it. It deserves the reputation it has as a real nice example of a zoom.

BTW - the business of wide field isn't all that intuitive either. When you look at the chart above there doesn't look like there's much difference. That actually represents about a 50 percent increase in the amount of sky you're seeing. Like wu ith objective diamter, area is a deceptive number that sometimes catches you off guard when you're dealing with a linear diameter instead.