Re: [ATM] [ ] making Foucault tester

["Bob May" <rmay@nethere.com>]

Depending upon the d mLED, the light may be guassian in naturre
of enough variability to affect the readings.  Polishing off the
lens is a good idea as the lens is intended to make the light
more directional than it would otherwise be.  I most prefer the
LEDs that are frosty in appearance as these tend to be more even
in their light output and throw the light to a much more wide
angle.  The clear LEDs 9may be colored) are the ones that do the
narrow beams and those need badly to have the lens on the end
cleaned off.  You don't need to go far if you happen to get one
and you shouldn't as there is a wire that loops around the diode
and hits the diode in the center.  Just grinding off the end with
some fine sandpaper is usually enough.  The KE will cut the light
source properly and make for a nice l9ight.
Remember that it used to be that you'd put a ground glass screen
between the light source and the slit to make the light even in
intensit7y and the light source optically right behind the slit.
This was done in the days of light bulbs and flames (if you go
bak that far!) so that the light was even in its distributition.
Bob May

rmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net


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