Re: Light Meters

[busko at stsci_edu (Ivo Busko)]

"Wayne Jones" <waj at mnsi_net> wrote:

<snip>
> I just had a thought that if I bought that cheap light meter that George
> recomends maybe I could take measurements with the sensor both flat and
> vertical and then add them together. Would that be similar to having a
> cosine corrected light meter? If it is I think I will order one. I don't
> have even a small portion of your mathematical abilities and for me trying
> to do the math is just not any fun at all.
> 
I think so, if you average the readings instead of adding them together.
From what I could see with my crude measurements, you shouldn't be too
picky with the meter. Light levels change a lot from place to place in
the tank (in mine at least...) so you can get nly approximate or avergae
values anyway. 

> BTW I am now putting together a 6 lamp fixture which has individual
> parabolic reflectors for each lamp. I think that the main problem with past
> fixtures I have made is that the light in the tank is not evenly
> distributed. The top of the tank is much better lit than the bottom of the
> tank and this is probably true for a lot of other tanks. For instance, I
> don't think that many lawn type plants are particularily light demanding.
> They just happen to be placed at the bottom of the tank where there is not a
> lot of light. I am hoping that a better reflector design will reduce the
> drop in light intensity at the bottom of the tank.
> 

What is this reflector that you can fit 6 lamps over the tank ? The only
ones I found so far that are narrow (4") are the AHS reflectors, but even
with then its hard to cram 6 over a 24" wide tank.

> I would also like to point out that while DIY lighting is a lot of fun for
> me, I don't think I will ever be able to build a better lighting system than
> the ones that you can buy from AH Supply. The more I learn about lighting
> the more I come to appreciate what a great system they sell. I just can't
> seem to stop myself from trying to improve my setup though. Now maybe if I
> can just get a hold of some of those linear HO T5 lamps, I could go with 4
> individual reflectors, a 5' tank and ......
>
Agreed 100% on the AHS system. Hard to beat by any measure. As for the HO T5s, 
I did some research and gave up on using them. I quoted prices and availability 
of the Sylvania Pentron HO system. Lamps cost $14 apiece, but the 2-lamp 
ballast retails for $95 ! If you can find these ballasts at retail to begin 
with. I contacted a number of distributors and none carry then on stock. They 
can only special order them in cases of 20. 
 
> Wayne

- Ivo Busko
  Baltimore, MD

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