How to measure par ?

Blue brother

Blue brother

Well-Known Member
got some dual arcs coming in the next couple days and I want to know if there is any way of reading the spectrum of light at various points around the room, I hope someone understands what I mean lol. I'd like to be able to know if there were any spots where inconsistencies in the spectrum would occur due to the light from each arc not being mixed up properly.

Thanks in advance for ur replys dudes
 
Red1966

Red1966

Well-Known Member
Even a PAR meter (pretty expensive) won't give spectra specific data. There are devices that can do that, but you're talking thousands of dollars. I think it's called a spectrometer?
 
Blue brother

Blue brother

Well-Known Member
I done abit looking around and apparently they use something called a diffraction grate to further break down the spectrum. I dunno why but I thought I might be able to use a glass prysm lol.
 
Blue brother

Blue brother

Well-Known Member
Haha how cool, how will I be able to take different measurements at different points of the spectrum though?
 
auswolf

auswolf

Well-Known Member
Blue brother said:
Haha how cool, how will I be able to take different measurements at different points of the spectrum though?
Click to expand...
Yes the link I posted uses software, you just have to calibrate with a cfl.
Here's the spectrum of 430w hps, it also has the bulb dimmed to 250w to show
the effect on spectrum.image.jpg
Simple as taking a photo with your phone.
 
Blue brother

Blue brother

Well-Known Member
hyroot said:
http://www.apogeeinstruments.com/mq-200-quantum-separate-sensor-with-handheld-meter/

http://www.apogeeinstruments.com/ps-300-uv-to-near-infrared-range-spectroradiometer/
Click to expand...
Am I right in thinking the first link will just tell me the amount of total par at a said point? Where as the second will show me the total amount of radiation and the way in which its distributed between the different wavelengths?.

I need to be able to see if the light from what is essentially two different light sources is being mixed consistently.

Hypothetically I could have identical par readings at 2 different points in the room but The spectrum could still have different content at said point. I.e a blue area and an orange/red area.
 
L

LurchLurkin

Active Member
Just rent a PAR meter from a fish place. It's something like $20 a week with a couple hundred deposit which you get back when you return the meter.

A spectrometer will only tell you what wavelengths you have.

A PAR meter will tell you how much light you have that the plant can use.


US government study on cannabis found it can handle 2000microeinsteins per meter at 80F with 1200ppm co2
 
Blue brother

Blue brother

Well-Known Member
LurchLurkin said:
Just rent a PAR meter from a fish place. It's something like $20 a week with a couple hundred deposit which you get back when you return the meter.

A spectrometer will only tell you what wavelengths you have.

A PAR meter will tell you how much light you have that the plant can use.


US government study on cannabis found it can handle 2000microeinsteins per meter at 80F with 1200ppm co2
Click to expand...
A par meter won't work for my needs.
A par measurement will be like saying there's 3kg of food in my cupboard. What I wanna know is how much spaghetti I have, how much pasta sauce, how much bread etc.

Thanks though
 
L

LurchLurkin

Active Member
No you don't. PAR means photosynthetic active radiation, it ONLY measures light that plants can use.

You're thinking of a lumen meter, lumen is for visible light, not all of which a plant can use.

If you look at the light, is it cool or warm? Cool for veg, warm for flower. Then a PAR meter will tell you how much light is there that a plant can use.


A spectrometer might tell you that you have 680nm light and not a lot of 420nm...so you have lots of red and little blue... You can tell that by looking at it.
 
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