- I'm a relative newbie and just buying my first eyepieces for a 16" dob
I'm building. I received in the mail today a 6mm lens (not for the dob,
but for a 120mm refractor I bought used) that I bought used from
Astromart. It is a Smart Astronomy SA Long Eye relief lens with about
55 degree field of view. To look at it, it appears to have never been
used. But, when I hold it up and look thru it toward the light, I see
what appear to be 'flaws' in the glass. I've cleaned the glass outside
and made sure there is nothing like dust on the outside. My question:
is it 'normal' to see flaws in optical glass that appear like flaws in a
diamond or something? They appears as dark steaks, more or less.
"Where the people fear the government, you have tyranny; where the government fears the people, you have liberty." - Thomas Jefferson
- From: "Steve" <svanos2@...>
> is it 'normal' to see flaws in optical glass that appear like flaws in aSimple answer, Steve - no, it's not normal to see flaws such as you
> diamond or something? They appears as dark steaks, more or less.
describe. Even an old eyepiece should not have marks that appear between the
lenses, although it's possible for the exteriors of the eye lens and field
lens to develop minute scratches from too aggresive cleaning.
Lily Lake, Illinois