Hyperion 5mm vs Circle T 5mm

[gooseholla]

Baader Hyperion 5mm vs Telescope House (Circle T) Orthoscopic 5mm

Both eyepieces that I ordered arrived today, so I thought that it would be a perfect chance to try them out in my Celeston 8 inch Newtonian (1000m f/5).

Here are my thoughts after a couple of hours viewing.

The Baader is a huge lump. Wouldn't want to drop it! Very hard to find the correct place to position your eye. However, when you do, it is a very comfortable eyepiece to use in 5mm and c. 22mm mode. No real eye strain at all from using it for long periods of time.

Scope was out from about 4pm. Used the Baader in 2 inch c. 22mm mode to look at the moon. First thing I noticed was that there was a blue halo around the light side of the moon. Second thing was that it only stays in sharp focus for a few seconds near the centre of the eyepiece. Quickly everything goes soft and out of focus. Viewing later, c. 8:30 at the Beehive cluster, it was a big disappointment. Only the central few stars were anywhere near sharp. As they radiated out from the centre, they started turning into streaks of light very quickly. This was disappointing – though perhaps expected – for such a wide angle lens. A 32 mm 1.25” GSO plossl would win hands down for me for viewing DSO. It was very annoying viewing the moon, watching it for ages traverse across the large field of view... whilst 95% of the time it was out of focus.

Secondly, tried the 5mm mode on the moon. In a 2 inch barrel it will not focus; it needs at least another 2 cm or so to be able to focus. So I plonked it into a 1.25” holder and it focused. Ignoring the scracth and grease/dirt marks (which I have to clean at some point) I noticed it was a good image, but not really sharp. Finding focus was hard as it has a tiny focusing point. This was even harder on Mars – it would not focus at all well. In fact I gave up trying to foucs it, as by the time I had it had moved and needed refocusing and moving...

This brings us on to the Circle T orthoscopic. Lovely eyepiece and comfy to use. Plonked it in and it focused well on the moon. The views were better than the Hyperion in my scope. Sharper and more detail/contrast. Loved it. Mars was a delight. Detail was clear, the polar cap was bright and the darker features stood out well against the surface. In the Hyperion the darker regions were hard to make out and the polar cap dull, if in fact visible – it was hard to tell that there was a polar cap there. The 22mm mode would not focus Mars – it was just a small streak of light, nothing circular about it at all.

I suspect my scope needs collimating a bit further to improve the views slightly. However, the Orthoscopic is a big hit – love it. Going to get some more hopefully. The Hyperion... Hmm.... not so sure. I suspect it might be on the 'for sale' list in the next few weeks! Perhaps it is a very good eyepiece, but it isn't in this type of scope. Purchased on a whim for £35 delivered, but I don't think that it is for me. I'm glad I didn't pay nearly £100 for it!

[John]

The Circle-T orthos are great value - I just sold a 4mm for £20 delivered !.

The narrow field of view and tight eye relief doe get tiresome after a while though and sometimes a comfy eyepiece like a Hyperion is a refreshing change.

I'd give them both some more opportunities to show what they can do before deciding which to part with.