Dumb, Dumber and Dumbist

Hans · Post by **Hans** » Fri Jun 02, 2006 9:14 pm

Here's another one. I made a board with three screws in it to rest the MBDCG plates on. I placed the subject under it and illuminated Denisyuk style from above. I could not figure out why my plates needed at least 45 minutes settling time. Some times only a hologram was visible in a thin line diagonally across the plate. Well, I have figured it out. The plates were resting with the emulsion on the screws. Because MBDCG is a relatively wet emulsion, the emulsion has a certain viscosity. The screws were slowly sinking into the gelatin under the weight of the glass. This made the glas move. I spoiled many many test plates this way. When I placed a plate upside down on the screws the settling time was not a problem anymore.

dave battin · Post by **dave battin** » Fri Jun 02, 2006 10:14 pm

yes Hans, your learning the hard way!( which is the way most of us learned)!LOL Tell us Hans what else have you discovered?

Hans · Post by **Hans** » Fri Jun 09, 2006 11:45 pm

dave battin wrote:yes Hans, your learning the hard way!( which is the way most of us learned)!LOL Tell us Hans what else have you discovered?

Oh yeah, here is another one:

In the hotel, some days ago, I decided it was a nice puzzle to figure out what the fringe spacing would be of two intersecting coherent beams of light. I made a nice drawing in my note book and started to figure out the geometry. I came with the following formula: w=L*cos(a/2)/sin(a). Where L is the wavelength of the light in meters and a is the angle of the two intersecting beams. When I opened of Saxby's book afterwards, I found a different formula: L/2=w*sin(a/2). This caused me great frustration because surely my logical reasoning could not be wrong here. I tried to re-prove my formula in three different ways. But I kept coming to the same conclusion. I WAS RIGHT!!! The frustration grew, and I was determined to post a message about this on this forum. Luckily I later noticed the little note in Saxby's book that states that sin(a)=2*sin(a/2)*cos(a/2). This was some math I forgot from high school. With that little formula it is easy to re-work my formula in to the one in the book.

If I had just bothered to put some numbers into both formula's and compared the results, it would have saved me a whole day of doing math...

Colin Kaminski · Post by **Colin Kaminski** » Sat Jun 10, 2006 2:00 am

Hans wrote:If I had just bothered to put some numbers into both formula's and compared the results, it would have saved me a whole day of doing math...

Or, if you look at it another way, you got to spend a whole day doing math! It is much better than watching TV.

glajciorz · Post by **glajciorz** » Mon May 14, 2007 9:44 pm

Hi there.

3 weeks I fired SSY1 for the rist time.

After playing with it I noticed something looking like dandruff on the OC mirror. I couldn't remove it using compressed air nor IPA.

Today I looked at the OC under the microscope.

The mirror is damaged in its volume, not on the surface.

I was wondering why and remembered that during the first day I fired SSY1 I tried to make a hole in an aluminum foil. Using short-focal-lenght concave-convex lens held very close to the laser... Tell yourself the rest of the story.

Anyway, I learned something (in a painful way), the SSY1 with damaged OC is still lasing and it's good that I bought more than one laser and need only one pair of mirrors and one q-switch for my YAGNA

greetings

Adam

glajciorz · Post by **glajciorz** » Mon May 14, 2007 10:01 pm

Another one - once upon the time I was trying to modify a gelatine in a way so it would start hardening immediately after coating without the need of additional bath. So I mixed gelatine with water, heated it to 60deg.C and after the gellatine dissolved I added 5% of formaldehyde.

And I partly succeeded - no additional bath was needed. The worse thing was that no coating was needed too, because the gelatine gelled in a bottle in 50s. After one hour of swearing and trying to get this bloody gel out of the bottle I finally threw everything in KOH/IPA bath and after 20 hours or so I could finally reuse the bottle.

greetings

Adam

John Klayer · Post by **John Klayer** » Sat Aug 14, 2010 1:32 am

Here's the latest dumb thing I did. As you know, I've been doing cave holograms. I noticed that the better results were after about an hour of laser warm up. So I got the idea to put the laser, power supply, battery and cooling fan together in one box to lower into the cave so it would be ready by the time I got done rigging the rope to get myself down. The cooling fan was too much trouble - so what could go wrong - a turned on laser, insulated against damage and thus thermaly insulated? Did I mention that I made a window in the box to make sure that both green lights were on? By the time I got to the laser it was hotter than a firecracker.