MH bulbs and alligntment of the center

[Spar]

was looking closely at my MH bulb's that I have had for several months now, and noticed the center area where the bulbs have that shark-egg looking piece that the light starts-up at (sorry, best analogy I could come up with for a piece I have no idea what to call) is at an angle where what I would call the top or bottom is facing the sides of the hood rather than facing straight up and down.

think there would be more efficiency if it were facing straight down?

let me know if this is so butchered up with lack of lingo and I will just take a pic to explain it

 

[melev]

As far as I know, the orientation of the contents of the bulb make no difference at all as long as it works.

 

[Serk]

Here's a decent article on some research that was done on this subject:

http://www.advancedaquarist.com/2002/3/review

IMHO, it might make a difference, but if it does, it's bulb by bulb, and generally very minimal... And there isn't a hard and fast "Put it pointing here" rule...

 

[Spar]

nice article! pointing the focal point up towards the reflectors seems like the best idea to me.

i am still confused by what he meant in the different orientations. if the nipple is facing down, then which way would the higher intensity of light be aimed?

and how the heck do you find articles like this so easy? :lol:

 

[Serk]

@Spar wrote:

I hafta be honest I haven't re-read this particular article, but I think some of the original theory in discussion of the nipple wasn't that they produced focal point, but that the "dust" in the bulb itself that produces the different colors would pool in the nipple if it was pointing down instead of being suspended evenly throughout the bulb when the plasma was formed, causing the color to shift.


@Spar wrote:

Google is your friend... I just Googled on "metal halide nipple" and that article was the first link...

:wink:

 

[melev]

I asked Sanjay Joshi about the nipple thing specifically, and he told me it was a myth.

 

[mwolek]

The bulb is sealed and shouldn't get 'dust' in it...?

 

[Serk]

@mwolek wrote:

I was referring to the "stuff" inside the bulb itself, the stuff that's 'sposed to be in there...

Of course, thinking further about it, once the plasma arc is created, I'm sure things are tumultuous enough in there that it prolly doesn't really matter...

 

[washingtond]

I am using 4 XM 10K SE bulbs and have found that the nipple position of the bulb does make a difference with the coloration of the light. I have found that a 2 to 3 o'clock position gave the bluest color while the noon to 1 o'clock position was pretty yellow.