Yes, for the above plots, single point. 18 inches from the center of the fixture. Using an cosine detector (I also have a small integration sphere, fwiw) and a lab-grade spectrometer. Spectra power is numerically integrated across the spectrometer bins to determine a variety metrics such as the noted PAR, YPF, etc. e.g. “All spectrum set at 100%, open air, single point, 18” distance from center of lamp." It should be considered a “best” case type of measurement as far as intensity is concerned. The single point measurement is something of an industry standard, not really my doing.
A C++ version of the source code for the numerical calculation portion can be found here:
Not for the plots in the OP. Each set of data in the OP includes a statement on the measurement parameters.
Cosine detector. These are for measuring luminous flux and commonly used in radiometry for measuring spectral irradiance incident on a planar surface.
Misleading? Standard industry/scientific terminology and measurement techniques used throughout, to the extent of my resources.
Such data “could” be used to mislead if it is used out of context or the the measurement parameters are misstated, I suppose.
Inadequate. I assume when you say inadequate you mean “not enough information” to numerically design a grow room. E.g. PPFD over a defined area. I’d agree with that.
PPFD + PAR mapping is a desirable metric, and is correct if that is what your are referring to. It is additional work which, if someone requests it for a specific scenario, I’ll consider looking into it. In fact, I did consider spending the extra time but I have a variety of other projects that also need attention (plus, I needed to put the lamps into service). FWIW, open space, enclosed space, reflective walls, diffuse walls, etc have much more effect on the PPFD measurements than the single point, so the space would need to be well defined. Also, I’d argue that many other metrics are equally desirable, such as the actual spectral output, conversion efficiency (using the single point), and so forth.
edit: I’ve posted some additional notes on PPFD and how it relates in the thread below.
Well, this thread was not intended to provide such information. What it does provide is a piece of data for a limited set of commercial fixtures that might be useful in that scenario. Or, for whatever other considerations. It’s another tool in the toolbox.
What data is provided could be useful for making a rationale judgement as to whether the measured data, at least, lines up with the manufacturer claims. Or, it could be used to guide the tuning of the spectra in your grow environment. It’s data, not intended for use for pitching sales. The data can be useful in a variety of ways. It does require that the individual is able to interpret that data properly. As is true with most things in life.
The equipment required to measure spectra can be complicated and expensive and, as such, most do not have the resources and have little choice but to trust that the manufacturer is being truthful. And (how I feel about), making such data openly available certainly provides much more value than what many manufacturers provide for data which, in this industry, is the typical claim that the “car” has a V8 when in reality it has nothing more than a 4 cylinder.
To be thorough when evaluating a purchase, let’s see:
Cost
PAR spectra
Spectra outside of PAR
PPFD
Spectral Control (e.g. programmable spectra)
Control interface (dimming, etc)
Power dissipation / Conversion Efficiency
Waste heat elimination (passive / active)
Weight
Footprint
Safety Certifications
Environmental Sealing
Warranty
Wasn’t really the intent of this thread. It was mainly to provide spectral information on the fixtures I have access to. Perhaps adding additional fixtures as time and access allows. But, yea, we started to get into DLI and stuff…
Although, there may be a valid reason to go through the effort of compiling such information in a different thread. Just a bunch of work waiting for the value proposition.
Interesting, are you referring to their new generation of their lamps? If there is a concern about the accuracy of data on a specific fixture, we can set-up a scenario to gather our own data. That is, if the fixture is available.