On7/23/99 4:59 PM, Maggie Owens wrote:

>I don't know much at all (that would be, I really know nothing) about this 
>technology, which is why I'm posting this question. (So please be gentle!)
>
>What I am wondering is
>(1) are HID lights really all they are cracked up to be? and
>(2) Is there something about them that makes them *NOT* DIR, and if so, 
>what is it and why?
>
>Thanks in advance.


Maggie -

My understanding is that the HID lights are arc lights like most stadium 
and street lights.  That means they don't use a filament that can break 
-- but it also means they take a comparatively long time to heat up and 
start arcing.  (Anyone who's seen street lights or turned on the lights 
at a night ball field or tennis court knows what I mean -- first they 
start humming and light with a very dim glow, then they get a little 
brighter/hotter, then they arc to full intensity.)

You can see the obvious downside: as long as you never turn your canister 
off underwater, you have a bright, electrically efficient light that's 
more shock resistant than filament bulbs.  If you do switch it off -- 
either by accident or on purpose -- you can't switch it back on quickly.  
Obviously, with this characteristic, they're not appropriate for 
instructing and this could be a problem in an emergency.  

That's all I can think of off the top of my head.  I'm curious to see how 
they fare in real world use.




Best regards --

Bill

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