URL to check your PAR meter

[Delps8]

I contacted Apogee last week with questions about the accuracy of my PAR meter. The customer service rep gave me this URL which takes you to a page that allows you to compare the PAR reading that you're getting against the output from the sun.

It's well worth the 5 minutes or so that it takes to run the test.

 

[Delps8]

Glad to see that growers are getting something out of this. I tested Photone early last year and passed. I did another set of tests, just four readings, a few weeks ago. Photone was much higher than my Apogee but, when I put the data in Excel, it turns out that Photone was consistently 16% high. That's pretty cool.

I contacted the programmer at Photone with my results. He and I have traded email about his app and one of the issues we discussed was that the readings could be close if you put in the margin of error in my iPhone sensor + the MOE in the Apogee. That's why I contacted Apogee.

When I ran the clearsky test, I found that my MQ 500 is reading 2.4% high which means that, uncalibrated, Photone is reading really high on my iPhone XS Max. I'm pretty sure that I can calibrate out the variance on Photone but it's still a moot point for me. The hassle of putting on a diffuser and hoping that it's in the right place plus being able to use the wand with the MQ 500 make Photone interesting to me from an engineering perspective (30+ years as a software engineer including Apple) but it's not part of my grower's toolkit.

 

[NewToTHC]

Don't understand the time of day entry?. Say it is 1:30pm, what would the decimal equivalent the calculator is asking for?

 

[Delps8]

Don't understand the time of day entry?. Say it is 1:30pm, what would the decimal equivalent the calculator is asking for?

It's 24 hour time, expressed in decimals. 1 PM is 13 hours + 30 minutes is 05. hours =13.5.

 

[NewToTHC]

Thanks, will give it a try on my Android phone lightmeter app and see what the comparison is, certainly better than a wild guess.

 

[Sunasun]

Don't understand the time of day entry?. Say it is 1:30pm, what would the decimal equivalent the calculator is asking for?

Just take your minute amount and divide that by 60 to get the decimal.

Ex. 15 minutes = 15/60 = .25
30 minutes. = 30/60 = .50
45 minutes = 45/60 = .75

 

[On the Fence]

That's great for outdoor grows. My meter app lists many spectrums it tests and natural daylight is one. I use 3500K high output with 10% red and calibrated it according to light mfg par reading at 24". There is a correction factor to input till you get the correct reading at said distance.
Apogee referred me to Migro for the Bluetooth Meter to use with the PPFD app for android. Love it!

 

[Delps8]

That's great to hear. Thanks for the update.

 

[Delps8]

Since the original posting, I've learned that Apogee has an iOS app that has the same functionality as the web page but, as it launches, it fills in the position and weather data for your. Search for "Clear Sky Calculator" in the App Store.

 

[NewToTHC]

Appears to be available for Android phones as well.