Most hobby solar sensors will show 0w/m2 at night so to measure clouds at night you need a different solution
Stuart
For the solar in a jar it does not need much modification to do this, just a black bottom to the jar is all.
For the lab flask solar in a jar method is a little more tricky to add the black bottom bit its doable.
You need a sponge that's about an inch in depth cut in a circle to match the lower half of the lab flask.
cut some aluminium foil to match the size of the sponge, glue it to the sponge, colour using a permanent
marker, it will need a few coats to get it black., make a hole in the center for the probe to fit. Now for the
tricky part and why it had to be a inch thick and foil needed, the aim is to get it up the thin neck of the flask
and it to open up once inside, that's the sponge's job, so gently scrunch up the sponge so it will fit into
the neck of the flask and push it up, give it a moment to open up some, then using a long, thin tool, gently
press the sponge to the top of the flask to open the sponge fully, you can then use sommat like a crochet
needle to gently hook the sponge using the center hole and pull it back to the bottom of the flask, then just
fit the probe and stopper and there ya have a dual solar/night cloud sensor, I used that type for a good few years up on my mast and it work well.
Also used the upside-down jar method after i moved having lost the flask, just painted the inside jar lid
black, hence upside-down method
The above will only work with weather display or other software that can setup both homemade sensors.
They also need tweaking for the summer time temps and winter time temps.
I am currently using a homemade probe in a jar method for my night cloud on my Davis setup, its not actually
a jar, its a low bowl, colour black internally, added polystyrene as a layer that covers about 1/2 the depth
paint that black, made a small hole for the Davis probe, then covered with a phone screen protector and
stuck it in place with outdoor tape and fixed in place so it didn't blow away, this too works very well once
you get the settings right, you also need to tweak during winter/summer times due to temp change.
That method to can be used as a dual solar sensor if i needed it to.
Whilst quite crude methods they work very well
See davis method graphs for day and night below
As long as the night cloud temp sensor goes about 1C below the air temp then you've got a night cloud
sensor, the 1C is so you have enough range for the few cloud types
