BBC terminology boob?

People

In discussing the great 28" refractor the expert Greg repeatedly
mentions *sleeks* as one of the limiting factors of optical glass
production in the past.

What he really means, of course, are *striae*. Areas within the body
of the glass which have a slight difference in refractive index to the
majority of the glass. These are usually caused by stresses induced in
the glass as it cools. Optical glass annealing in the late 1800s was
not the fine art it is today and such large blanks as the 28" were
incredibly difficult to produce with perfect homogeneity.

*Sleeks* are an (almost) insignificant cosmetic surface defect as a
result of imperfect optical polishing. Though obviously undesirable
they would be invisible in the image of almost any astronomical
instrument except (perhaps) for a coronagraph.

If one is trying to educate the 'unwashed' then I do think the correct
terminology should be used. Otherwise the authority of the so-called
"expert" is undermined and nothing further he says can be taken at
face value without checking.

I know I'm a complete pedant but somebody has to make a stand! :-)

http://news.bbc.co.uk/today/hi/today...00/7972981.stm

All together now, children. Repeat after me! Striae *not* sleeks! ;-)