Plossl v Ortho

[mickoking]

G,day cobbers.

I am in the process of updating my kit and I need an eyepiece (5-6mm) for double stars which I have recently aquired a taste for. What is better Plossl or Ortho ?

Cheers in advance.

[Starkler]

At such short focal lengths an ortho will be easier to view through than a plossl.
Both are an exercise in squinting through a tiny lens with the ortho a bit less painful.

Why not go for houghys 6mm lv in the buy/sell section ?

[janoskiss]

hehehe! What's better an orange or an apple?

Orthos have more eye relief for a given focal length. (15% more ???)
Plossls have about 10% more field of view.
Apart from that it's all about build and optics quality. You get what you pay for, more or less. ;)

[janoskiss]

Oh, 5-6mm. Orhto is better because of eye relief. Like Geoff, I woudn't bother with either. I'd just barlow my 12mm ortho (which is a sweet comfy combo).

[mickoking]

Sounds like the ortho's the go with the extra eye relief. As I will be viewing doubles the FOV is not too important. I specifically want plossl or ortho coz they are 4 element eyepieces and I want the highest definition and contrast. The 6mm LV is 6 elements ( I think) and using a barlow will add more glass to the optical path.

[janoskiss]

If you have glassophobia, then get a Huygens or Ramsden. Just 2 elements, so they are twice as good as a Plossl or ortho. :P

[mickoking]

:rofl: :rofl: :rofl: :rofl:



* Seriously, my old Meade series 3000, 16mm Plossl (4 elements) is a better performer light transmission/ contrast wise than my 13mm Nagler ( 7 elements) ;)

[janoskiss]

I can believe that. The Nagler is a bit of a light hog. :P Even the inexpensive 13mm Stratus with its 8 elements had no trouble keeping up with the 13mm T6 on how deep I could go and how faint I could see.