"Loren A. Coe" wrote in message news:77S%b.425546$na.844884@attbi_s04...
Lennie the Lurker wrote:
"Loren A. Coe" wrote in message news:07A%b.405328$I06.4401672@attbi_s01...
Lennie the Lurker wrote:

also, does anyone know what a "HOM 1-1.8mm" objective would be,

THis would be roughly 100X, "HOM" means oil immersion. Combined with
10X eyepieces, roughly 100X, but won't show much without using the

yes, it says 96x (from the Ebay description).

Yeah, and pardon the missing (0), that should have been 1000X. 96X is
pretty well a standard for older AO stuff, 97X for B&L. They're
interchangeable.

drop of oil between the lens and the coverslip. THe oil corrects for
the dispersion and difraction of the glass/air intersections. the 1.8
is the focal length of the lens in milimeters.

what's with the range, 1mm-1.8? another lens is a "Planoacrho 40x/.66",
is that of particular interest/value? these are all supposed to be AO
lenses. it s/b here on Tuesday, according to the Fedex tracking site.

Ok, I'm thinking a little screwed up here. It's a 1mm focal length,
f1.8 lens. The 1.8 is also where the diaphram on the condenser should
be set for the best definition. I shouldn't say "f1.8", it's an
optical ratio, but I don't understand exactly what it is. But, like a
camera, lower numbers, brighter picture. 1.8 is pretty well standard
for oil immersions. (Older standard. newer ones have a lot more
glass.)

the 95x w/be 950x with a 10x ep, right? can that power actually be
expected to function well on this class of instrument (assuming good
condition)? i have talked to the seller and i expect the objectives
came with the microscope, so it is missing the lower (4x) objective
in favor of the 95x.

It should run to 960, and maybe even get away with using 15X
eyepieces, but usually that only runs into having a bigger image and
not as much detail. NOt having a four position objective turret, I
switch back and forth from the 4X objective to the 100X, depending on
what I need at the time. The higher power lens isn't really practical
with things that are swimming, too hard to follow them. The 96X was
not all that common, compared to the 4X or 6X. Lower powers are nice
to have at times.

there was an One-Sixty Dark Field that closed w/no bids at 175.00(res)
with three lenses marked "infinity". the seller didn't seem to want
anything to do with possible condition issues so i abstained. maybe
that was a good deal if the objectives were good.

The 160 is an infinity corrected scope, those lenses are different
from the achromats. One element of the lens is built into the scope
itself. Making a dark field is only a matter of finding a condenser,
otherwise the scope is the same. I have most of the accessories for
an older Bausch that I bought some years ago, monoc, binoc, trinoc,
darkfield, polarized, there's quite a bit available for some of them,
for others, unobtainium. Phase contrast is another that's nice, but
the objectives and the condenser have to both be for phase contrast.
It's a bear to set up the first time, too. Annular reticles in the
condenser that have to be exactly aligned with the objective. I don't
have one.

i notice most of the chinese offerings have "spring-loaded" objectives
in the higher power ranges. thanks again, especially for the advice on
picking lenses. --Loren

Swift, from Japan also has the spring loaded objectives. Beautiful
for high schools, but I'm not sure how well they relocate after being
moved. Think I paid something like $30 for a 100X Swift objective,
seemed ok, but it was for a scope I was donating. I've seen some of
the CHinese stuff, the optics aren't bad, but if you ever clean the
RT-44 out of the mechanism, you'll never get it to hold a setting.