Orion LHD - Reviews?

[40Eridani]

Has anyone compared these to similar focal length Naglars/ES82s ?

[bladekeeper]

Hi David,

The Orion LHD are certainly attractive-looking eyepieces. I haven't read many reviews on these from forum members that I recall.

Anyway, this post should hopefully give your thread a little bump.

[Ruud]

The LHD are Long Perng eyepieces. See here:
http://www.longperng.com.tw/goods.php?act=view&no=196

Not much information there. That's a pity: the field stops would give an indication of the true fields of the eyepieces, and how much pincushion distortion they have.

The "clear apertures" of around 30 mm that Long Perng list are not the field stops of the eyepieces! For 80° eyepieces with zero excess pincushion, the field stops should be:

focal length    Ideal field stop
4mm               5.59 mm
6mm               8.38 mm
9mm               12.57 mm
14mm             19.55 mm
20mm              27.93 mm

If the real-life, measured field stops are 5% smaller than these ideal values, as is the case for many eyepiece designs, then the 80° afov of the LHD is a by pincushion distortion inflated 76° afov, showing the same true field of an ideal 76° eyepiece would, with extra pincushion distortion added.

The field stop diameters of Morpheus eyepieces are close to ideal and although they have a 76° view, they might well show the same true field as equivalent LHD 80° eyepieces.

The Morpheus have larger eye lenses too and the Morpheus are very, very nice for a better price (at least over here).

By the way, having larger eye lenses combined with a smaller afov, the eye relief of the Morpheus must be greater than that of the LHDs.

Knowing how good the Morpheus are (I have the 4.5, 6.5 and 17.5 mm and they are Delos quality) I'd say go for them and save some money.

Mind though that the Morpheus 14 mm is reported to be weak at the edge of the field, so I can't recommend that particular one.

[Lady Fraktor]

Long Perng typically makes good eyepieces but the eye lens of these is to small to produce a 80° AFOV so either they are not 80° or they do not have 20mm eye relief.
One of those two is wrong.