Weird Russian ortho

[markse68]

I picked up this Lomo microscope ortho on eBay- incredibly cheap I think I paid £15 for a pair of them! And it’s a bit special! Well different at least  it’s a 12.5x which (250 /x) makes it a 20mm. It has a really small field stop- must be no more than 30 deg. It’s like looking through a McDonald’s straw but it’s oh so sharp and contrasty and completely free of any colour fringing or any detectable distortion or aberration! Earlier this evening it held its own against all the other eps giving lovely views of the moon and Venus in the Telementor. I don’t know if it’s actually sharper or if it’s an illusion brought on by the narrow fov but I keep going back to it. Daft huh! 

The plan is tonight to try it on Jupiter and Saturn with the 8” dob. I’ll compare it barlowed against some 10mm eps including the BCO, and unbarlowed against an 18mm ortho. What fun! 

Edited May 24, 2020 by markse68

[John]

That and the Zeiss look like microscope eyepieces to me.

I've heard that they can work very well in scopes though and Lomo, like Zeiss, can produce really nice optics.

 

[markse68]

Yes they are John! The more modern Zeiss on the left isn’t an ortho though- in fact it doesn’t look to have much glass at all yet has a pretty wide field sharp almost to the field stop. It maybe a plossl 🤷‍♂️

Edited May 24, 2020 by markse68

[Louis D]

2 hours ago, markse68 said:

Yes they are John! The more modern Zeiss on the left isn’t an ortho though- in fact it doesn’t look to have much glass at all yet has a pretty wide field sharp almost to the field stop. It maybe a plossl 🤷‍♂️

Possibly an aspheric 3 element.

[markse68]

Well that wasn’t very conclusive 😂 The little Lomo didn’t disgrace itself against the BCO or the others and the small field framed the planets nicely but a wider field makes life easier with the dob so this one will stay with the telementor I think. Jupiter had a very interesting moon pattern last night- 3 moons clinging tightly to its limbs and the fourth a long way off looking on