Hesalite Crystal -- Why?

by andrema Fri 07 Jan 2011, 10:26 pm

I did a little digging prior to buying my Speedmaster and I found this interesting -- from the Omega site.

Question - Why is the Speedmaster Professional "Moon Watch" fitted with a hesalite crystal?

Answer - The Speedmaster Professional is worn by astronauts in outer space. When NASA chose this watch, they requested a hesalite crystal, which "unlike a sapphire crystal" does not break into tiny fragments on impact.This feature is very important for astronauts, as the tiny fragments of a broken sapphire crystal would pose a danger in a zero-gravity environment.

Hesalite crystal facts -- from http://omega.watchprosite.com/show-forumpost/fi-677/pi-3285826/ti-537576/s-0/

Hesalite or from other supplier could also be brandname Perspex. Both of them a PMMA sheet

Tradename Material Manufacturer

Hesalite PMMA sheet G-S Plastic Optics gsoptics.com][url=http://gsoptics.com/]gsoptics.com

Perspex PMMA sheet Lucite International [url=http://www.luciteinternational.com/]www.luciteinternational.com]www.luciteinternational.com][url=http://www.luciteinternational.com/]www.luciteinternational.com

Proporties of the materiel is:

• Exceptional light transmission with virtually no colour bias - even in thick blocks.
• Excellent resistance to outdoor weathering.
• Good resistance to impact.
• A high gloss, hard surface.
• High tensile strength and rigidity.
• Easily thermoformable with simple workshop tools.
• Easy to clean.
• Capable of being fully recycled.

by cali kid Sat 08 Jan 2011, 12:33 am

Great to find out what ive been told is true, thanks for all the info Mark!

by docrwm Sat 08 Jan 2011, 8:48 am

Mostly its because it was the highest tech available in 1967. Wink

by jimyritz Sat 08 Jan 2011, 8:59 am

That's excellent info...not being an astronaut I went with Sapphire...didn't want to be bothered w/polishing the crystal...either way, the Speedy is a sweet watch...

Mike