Q: LUX / SQM measurement
ESP32 mySQM+ Sky-Meter/Weather Station with loads of features
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Hi Robert,
yesterday successfully updated to the latest FW version and seems to be running very well but also in combination with the old WIN-App. Thanks a lot!
I have a question about the measurement of the SQM / LUX-value. There are 2 embedded sensors for IR and "full-spectrum" light. With this it is possible to measure IR and visible light.
I found this in a description from Adafruit:
*The best part of this sensor is that it contains both infrared and full spectrum diodes! That means you can separately measure infrared, full-spectrum or human-visible light. *
Does the sketch use only the measurement for human-visible light as I think this is the correct value for SQM measurement? I have seen that channels 0 and 1 are used for some calculation, but could not find the answer.
Cheers
Hardy
Last edit: elythomaslumber 2022-02-22
Hi Hardy
The code started off (a long time ago or at least it seems so) based on Nacho Mas example
https://github.com/indilib/indi-3rdparty/tree/master/indi-duino and the original work is done by Nacho Mas.
But of course the code used in mySQM+ now looks a lot different, and has evoled into something with different ways of handling light levels and changes in light levels compared to Nacho's code.
The code has had the advantage of having been tested in comparison with the unihedron meters, giving very similar results. I used to own a Unihedron, but sold it, and though I personally have not compared the readings myself (my unihedrom was sold before the mysqm+ was developed), there are users from the group that report this to be true.
There are 4 application notes from TAOS inc. These application notes discuss in details equations associated with the measurement of lux and its approximation to the human eye. If you are intersted please email me at yahoo or gmal and I can forward them to you. They are by nature technical notes.
Regards
Robert
Hi Robert,
not necessary to send me the notes.
A guy in a forum told me some weeks ago to use a IR filter in front of the sensor. But that information was not related to this used specific sensor.
So I had a short look into the sensor specification and have seen that the sensor uses 2 channels.
And than I was comming up with that question.
I will not use the measuring values for any science examimantion and I believe that there is no huge difference if the IR is included or not.
The measurements I did so far showing me Bortle 6-7 as I am living in an "official" Bortle 5 region. But I always had moonshine during the measurements behind my home and my sensor was loacted close to the house front (norther direction) but white walls.
I´m waiting for a moonless night and will place the detector more away from the walls. However the cloud detection is the mainfeature I will use...
Thanks also for the link to the Indi-3rd party driver!
Cheers
Hardy
That indi code would not work with mysqm+ as a different protocol is used, but could probably be modified to work I suppose.
the mySQMWeb runs on a Pi and gives all the fancy graphics etc
...fancy graphics sounds great! ;-)