Hello, i just wanted to tie this in with the conversation we were having about the accuracy of the AMTAST Quantum Par Meter.
Well, i had a full moon on a clear night last night and went out with the meter to see what it would tell me and it didn’t tell me anything. 0000 across the board. It should’ve at least read 10 PPFD right?
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I think it’s pretty well noted you shouldn’t expect to get any measurable radiometric light energy from moonlight. Even on a clear night with a full moon. This is why moonlight doesn’t interrupt photoperiod plants from flowering outside.
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Ok, i was just going off of a Dr. Bugbee video i watched where he said that on a clear night with a full moon it has 7-10 PPFD. At least thats what i thought he claimed. He was also referencing office lighting also so mabe i confused the info. It was over a year ago i watched the video.
But that does makes sense that if it doesn’t affect the plant then theres no PPFD.
Reminds me of the, if a tree falls in the forest and theres know one around to hear it does it make a sound. I still don’t get it… hahahaha
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My father in-law would use that line but said this way.
If a tree falls in the forest and theres know one around to hear it, is man still wrong?
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The riddle is deep. I know. It makes you think though.
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I doubt it. This source shows that a full moon produces an illuminance of roughly 0.1 lux. Using the table provided here and taking 4000K as the moon’s color temperature, we get:
PPFD of full moon = 0.1 lux / 277 * 4.56 = 0.00165 µmol/m^2/s.
No. The PPFD is > 0 and the radiation is measurable, but your instrument isn’t sensitive enough to do so and the PPFD is probably too low to affect the plant.
PS - If a man falls in the forest and there’s no one else to hear it, are his utterances still profanity?
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This clears it up for me thanks. I wished i was good with math like that but i am not. Thank you for doing the work and posting. I was thinking my device was way off but i am getting decent results with it so it can’t be that far off. I give it a 75% drift either direction when i take my readings. If it says 600 ppfd then i give it either i am at 675 or 525 ppfd to make up for its inaccuracies.
PS: i say it is.
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No problem – calculations like that barely qualify as “math” in my professional life.
For the AMAST or the Photone app, you should allow for a potential error of ±10%. So, if the AMAST reads 500 PPFD, the potential error is ±50 PPFD and the true PPFD is somewhere between 450 and 550. If it reads 750, the error is ±75 and the true PPFD is between 675 and 725.
When comparing AMAST readings with Photones, you should allow ±10% for both. So, for example, if one reads 900 and the other reads 1100, they agree, given the expected error range:
900 * 10% = 90; error range = 900± 90 = 810 to 990 PPFD.
1100 * 10% = 110; 1100 ± 110 = 990 to 1210 PPFD.
PS - That’s what his wife says, too! 
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Doing research. That was incorrect info that I posted hence the delete.
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@MartyMarajuanaseed…thanks my friend I’ve been waiting to see a thread dedicated to the diffuser your speaking of and I wanna thank you for checking it out. I’m definitely sold. @JPhoenixX you also helped and of course @Venturi who also recommends exactly the same. Ya’ll continue to have patience it’s a lot of reading to do on ILGM forum. Thanks again.
The Photone app is pretty accurate with the right settings and using the diffuser.
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