Three Hyperions

[cloudsweeper]

I’ve had the Hyperion 10/68 a while, but never went down the path of using Fine Tuning Rings to change the FL – too fiddly. And I no longer bother with removing the nosepiece for an increased FL, since that produces more edge aberration.

 

I then bought the Baader Aspheric 36/72 mainly as an occasional replacement for the big ES 30/82 and the Revelation Superview 42/65 (good, but limited).

 

I like the look and the feel of the Baaders, as well as their large eye lenses and eye relief, and of course the price. The 10mm is dual-fit, so can be used conveniently with other 2” EPs (some with “permanent” adaptors). The Aspheric is essentially already a 2” fit, but has an adaptor for 1.25”, but this brings the AFOV down to about 51deg.

 

Because of the above, I decided to fill a gap (mainly in the 8SE’s range) with an 8/68, giving me:

 

Hyperion Aspheric 36/72: 6-element, 384g. (The aspheric correction is said to keep the number of elements and weight down.)

Hyperion 10/68: 8-element, 376g.

Hyperion 8/68: 8-element, 365g.

 

Much has been said about these EPs of course, so I thought I’d do a quick, subjective test on their edge-of-field performances:

 

	f/10 8SE SCT	f/5 ST120 Frac
Aspheric 36/72	Exit pupil likely to cause a little eye astigmatism at edges, and some astig. was seen with/without specs. Down to EP then, perhaps aggravated because of larger AFOV?	Eye astig. would be more pronounced due to large exit pupil. Again, astigmatism was noticed, but again, specs didn’t make any noticeable difference.
Hyperion 10/68	Sharp at edges, with/without specs.	Just a little field curvature detected, but no noticeable astigmatism.
Hyperion 8/68	Mag x254, so stars less sharp, but no noticeable deterioration at edges, with/without specs, though harder to tell!	As above.

 

CONCLUSIONS:

 

In the 8SE, there was a little astigmatism with the Aspheric, but it was not distracting, and better than with the Revelation 42mm anyway. Field Curvature was not expected in this long FL ‘scope, and astigmatism often overwhelms that anyway. So all three performed well or very well, as might be expected in a slow ‘scope.

 

As for the fast frac, the edge effects were seen at the typical point about 2/3 out from the centre. The FC was very slight, and hardly a problem in the view. And it was perhaps in no small part due to the ‘scope.

 

So the 10mm and 8mm performed well in both ‘scopes, without severe or distracting aberrations. The surprise was that the Aspheric showed astigmatism in both ‘scopes, whether specs were used or not, and although it was not severe, it indicated a poorer overall performance than with the other two Hyperions.

 

I know these tests have their limitations, and would be interested in other members’ comments.

 

Doug.