Tessar
The Tessar is a famous photographic lens design conceived by the German physicist Paul Rudolph in 1902 while he worked at the Zeiss optical company and patented by Zeiss in Germany; the lens type is usually known as the Zeiss Tessar.
A Tessar comprises four elements in three groups, one positive crown glass element at the front, one negative flint glass element at the center and a negative plano-concave flint glass element cemented with a positive convex crown glass element at the rear.
Despite common belief, the Tessar was not developed from the 1893 Cooke triplet design by replacing the rear element with a cemented achromatic doublet. In fact, Paul Rudolph designed the Anastigmat with two cemented doublets in 1890. In 1899, he separated the doublets in the Anastigmat to produce the four-element, four-group Unar lens. In 1902, he realized that reversing the two rear elements of the Unar and returning to a cemented doublet would improve performance; he named the result "Tessar", from the Greek word τέσσερα (téssera, four) to indicate a four-element design.
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It's Okay
by: Des'reeSun is up should be feeling great,
your feeling rough got too much on your plate,
a busy day got a lot to do,
a heavy head you think you've caught the flu.
Something deep inside begins to stir,
spirit, conscience your not really sure.
It's gonna be okay...
It's gonna be okay...
Another day your late for work,
the shower's cold you ain't got no clean shirt.
A cup of tea just might do the trick,
the milk's gone off by now feeling sick.
Something deep inside begins to stir,
spirit, conscience your not really sure.
It's gonna be okay...
It's gonna be okay...
We laughed, we cried, we shared along the way,
we did some things we knew we shouldn't do.
So after all what's this life living for,
work it out or head straight for the door
It's gonna be okay...either way
It's gonna be okay...
You close your eyes, try to sleep.
Scold yourself for hours that you keep.
Drifting off will I dream tonight?
In my dreams perhaps I'll get it right.
Something deep inside begins to purrr,
spirit, conscience your not really sure.
It's gonna be okay...
It's gonna be okay...either way