Re: Pix of A. pellucida

I think that it is beyond the limits of classical LM. Much is placed
on NA for resolution, and for good reason. However, in the AP
respect, Lamda (wavelength) is more important...not to denigrate NA.

Hmmm. I understand resolution as a function of N.A. *and* wavelength. I
isolated the shortest wavelength I had a detector for (soft UV) *and*
used the highest N.A. I could get (1.4). The rest was about contrast.
Can wavelength be MORE important? Maybe from a SEM perspective...?

Let's be clear. For A. Pellucida under SEM or LM specifically. SEM is
the only way to get useful images of the pores themselves. It is
waaaaaaaaay beyond the limits of classical LM. You win that one hands
down!

But once the pore morphology is known (we establish they are uniformly
round for example) then LM can achieve measurements accurate to 10nm or
better.

I used astrometry s/w. Given very well calibrated images (bias, dark
and flat frames are essential) the location and 'diameter' (magnitude)
of a star in a digital image can be calculated to 1/100th of a pixel! I
found that it works equally well on diatom pores and the delta
positions yield direct measurements of pore centre spacing to near-nm
resolution. However, I'm not sure if 'magnitude' can be scaled as pore
diameter to the same resolution. Your images and measurements could
establish that. Of course, proper confirmation would need the same
samples as you - before you ruin them with (what I perceive as)
horribly destructive observation techniques ;-)

Note: there's probably dedicated s/w catering for all this and more,
but I already had the astrometry s/w (for it's intended purpose) and
didn't look further; so I know nothing about microscopy equivalents.

Anyway, this just shows the near-nanometre scale is not the *sole*
preserve of you SEM jockeys! Resistance continues. We are not yet
absorved [sic] ;-)

Cheers
Beats

PS. Do you put specimens 'under' a SEM? Is that the phrase you use? If
so; "hahahahahahaha" ;-)

.

Relevant Pages

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