T5s vs. MH... What would be the ultimate faceoff?

[Sanjay]

OK.. time to start thinking about the testing, now that the semester will finally be over next week.

I have been mulling a few ideas on how to make the testing easier to do. I cannot see spending hours testing the fixtures and collecting the data.

One idea was to build a simply XY robot, but that would still require manual recording of the data.

A simpler idea that was presented to me by one of my colleagues at work was to use a CCD camera and take a picture of the light distribution (essentially giving us 1000s of data points in one shot), and using some image processing software to extract the data. I kind of like this idea since it would make it a lot easier to collect the data. Unfortunately, right now I do not know much about the camera's and filters taht could be used todo this. May have to start looking at some optics catalogs.

Anyone with experience in imaging with CCDs and image processing willing to help do this ?

sanjay.

[hahnmeister]

I dont see how that would work because the camera is a passive sensor, and the light that the fixture makes will most likely not be reflecting to converge at any point... so the sensor readings would vary depending on any point. I mean, you are using a surface to make a grid, a surface that reflects (otherwise it would be black). But the if some rays reflect towards the sensor, and others dont, the data would be incorrect, right? Wouldnt the surface be like a mirror? And if so, a camera wouldnt work then, right? You would have to find a surface that would converge all of the light towards the camera... otherwise, its like you are trying to take readings from a reflector(reflection) of a reflector that would neither converge or diverge the light.

The only way I would see this working is if the surface was somehow polarized to converge the light (but that would diminish rays of light that are at more of an angle), or a large photofilm. If you used some large photosensitive surface/film, a 'polaroid' of sorts, you could capture a photo of the reflector... but then you have time to deal with.

The Lego robot in Germany is designed to auto log the data, so if you were to make one just like it, you could bypass the manual input part.

I dont know if you have something like this at PENN St., but at Milwaukee School of Engineering, they have a Lego League, and Im sure they could come up with the design for the data capturing/logging. I was thinking something along the lines of a 68HC11 controlled legobot.

[Sanjay]

There are devices commercially available to do things like this.

http://www.pro-lite.uk.com/Light/Rad.../Radiant2.html

sanjay.

[The Grim Reefer]

It looks to me like setting up a new system of measuring the output is going to be a project in it's own right. I know from my days fixing fax and digital copiers the CCD's have to be calibrated (white Balanced) to correct for inconsistancy in the lamp output along it's axis but also in the way the lens captures the light. You would have to come up with a way to solidly illuminate your whole test target evenly just to get a baseline.

I think measuring the output on a 3" grid is plenty accurate enough for us to gain an understanding of the light distribution of the two systems.

[Wetline]

Everyone appreciates the vast amount of time that you have invested into the MH testing, as well as the planned testing of the T5 bulbs!

What is the next step in the testing of the T5's or when would you estimate any results to be announced?

Thank you again for what you have done for the reef hobby.

[SeanT]

Any test data yet?

[Sanjay]

OK.. after evaluating some of the options on how to make the data collection easier on me, I have decieded to use one of the industrial robots in our lab to help me in positioning the sensor at the various grid positions.

After playing with the robot today, to get a sense of the work envelope, it seems I will be able to work with a max grid of about 48" X 30".

I have not yet finalized at what distance from the light fixture should the readings be taken. Right now I am thinking that most people would run the fixtures about 3" from the top of water, which would rougly put the lamp centers at around 6" off the water. So using 6" plus some standard tank depths (18", 24" and 30") I am thinking of taking 3 sets of reads at distances of 24",30",and 36".

Since I wont have the time to redo this, I have to make sure what I do will be useful.

If I can figure out how to get the robot to talk to the data logger, I may even be able to automate the whole process, making it easier to collect the data.

sanjay.

[jamesdawson]

Your the best Sanjay!

You may want to consider testing them a little closer though. Perhaps at 12", 18" and 24" or 18", 24" and 30".

James

[Ti]

ooo robots!

[hahnmeister]

See you at Foster and Smith Sanjay.

[IslandCrow]

I'd like to see a 12 or 18" reading as well if it's possible. It would give a bigger delta to show light attenuation from the mid/top of the aquarium down to the sandbed. I think most people keep their more light demanding corals within about 12" or so of the surface, so it would be very worthwhile data.

[The Grim Reefer]

Realistically the T5's should be at least 4" above the water but then again most people have sand beds too. I think if it were me I would add 4" to the popular depths and call it good. 22, 28 and 34" is going to give us plenty of data to make a well educated guess as to the PAR on tanks in between those sizes.

One other test you might be able to add with little time of hastle would be to measure peak PAR running 2, 4 and 6 lamps at each depth just to see how much adding more lamps add to the intensity.

[horkn]

Originally posted by The Grim Reefer
Ok, 1 more post and then stay out

I measured the Aquactinics reflectors against Ice Cap's with a slight advantage going to the Aquactinics reflectors. On the other hand Aquactinics use WH ballasts, not the best for T5.

I do have to add that using WH ballasts does work just fine.

I ran my 3 original 39w t5ho bulbs for 0ver 2 years (like 27 months) all driven by a wh5, and the bulbs looked better at the endcaps than bulbs in a teklight that had less months on them.

I do suspect the ballasts in the tek lights are sub par for t5ho use, even making the WH ballasts look to be a better choice than whatever they are running.

sanjay, you should test a WH ballast in running your t5 tests as well -although maybe not for a MH vs t5ho battle

[hahnmeister]

The Tek ballasts are universal triads if I remember correctly. Thats up there with Advance, Sylvania, etc...

[MarineGirl411]

Any news yet????

[horkn]

Originally posted by hahnmeister
The Tek ballasts are universal triads if I remember correctly. Thats up there with Advance, Sylvania, etc...

I just find it funny that with an instant start on the WH, and programmed start -if they are triads on the teklights- that the bulbs on teklight look worse for wear on the ends of the bulbs with a lot less run time than my bulbs that ran for over 2 years on a wh5.

esp after all the guys here on RC said that the WH ballasts would prematurely wear out t5ho bubs with their instant start.


Jon, I still have those 3 bulbs if you would like to run them on your par and spectro meter, for the hell of it....

[The Grim Reefer]

I think the issue with the Teks is heat, not the ballasts.

[horkn]

Grim, I bet you are right.

I forgot about that issue

[hahnmeister]

horkn, which 3 bulbs are they...? Sorry: I be busy lately...

[jamesdawson]

H

[insanefishguy]

Just out of curiousity, what size tank is that hahn? I have been thinking about setting up a 40breeder with a single 175 halide and wondered what the lighting coverage would look like.

[hahnmeister]

That tank with the light mover is a 125g, aka 120XL according to ELOS. 48x30x21"h. The previous pics on the other pages with light levels listed are 40Bs.

[The Grim Reefer]

Thats a cool tank Hahn, I'd like to do something like that with a big ol carpet anemone in the middle someday.

[rEd86]

Sanjay,

I am thrilled that you are taking the time to do this. I am going to be purchasing a new light system for my 180 and have struggled on which direction to go. (not that there's a bad choice necessarily, I think it's more a matter of personal preference) It will be good to see some data to validate what many people have been saying.

Like many others, I am curious about the process you use for this. I have read many of your posts here on Reef Central, as well as on your site:

http://www.reeflightinginfo.arvixe.com

Since you have been doing this so long, I wasn't sure if much has changed. (for example, do you still use the LiCOR LI-1800/12 portable spectroradiometer with a standard cosine receptor?)

In addition to the various depths, how many different points do you measure at each depth? What robotic arm will you be using to assist in speeding up the process?

Forgive me if the answers to these questions are posted somewhere – I couldn’t find them. If they are just point me in the right direction.

The tech geek in me always loves to learn about this stuff.

TIA.

--Ed

[thriceanangel]

I believe that he is going to be using something like this:

http://www.pro-lite.uk.com/Light/Ra...e/Radiant2.html

I don't even know what that is but he's using it.