Archive for March, 2020

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Allskypi Camera System Project

Mar08
by catz on March 8, 2020 at 11:31 and modified on March 8, 2020. at 17:35
Posted In: astronomy, tech


The allskypi camera system is pretty much operational, subject to a few additional tweaks in the upcoming days. This is the first report giving background details:

allskypiCameraproject20200308v2

Many thanks to the original project creator: https://www.instructables.com/id/Wireless-All-Sky-Camera/

Future upgrades includes: dark frame image processing out hot pixels, a wider angle lens for more sky coverage, more text annotations onto the images, and possibly some active cooling of the housing to reduce the camera sensor temperature.

pi@allsky1pi:~/allsky $ cat settings.json
{
“width”:”0″,
“height”:”0″,
“exposure”:”90000″,
“maxexposure”:”90000″,
“autoexposure”:”1″,
“gain”:”50″,
“maxgain”:”200″,
“autogain”:”0″,
“gamma”:”50″,
“brightness”:”50″,
“wbr”:”53″,
“wbb”:”90″,
“bin”:”1″,
“delay”:”1000″,
“daytimeDelay”: “60000”,
“type”:”1″,
“quality”:”95″,
“usb”:”30″,
“filename”:”image.jpg”,
“flip”:”0″,
“text”:”text”,
“textx”:”15″,
“texty”:”30″,
“fontname”:”0″,
“fontcolor”:”255 255 255″,
“smallfontcolor”:”0 0 255″,
“fonttype”:”0″,
“fontsize”:”0.7″,
“fontline”:”1″,
“outlinefont”:”0″,
“latitude”:”44.4N”,
“longitude”:”76.77W”,
“angle”:”-6″,
“time”:”1″,
“darkframe”:”0″,
“showDetails”:”1″
}

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Allskypi camera sensor temp review

Mar04
by catz on March 4, 2020 at 09:36 and modified on March 4, 2020. at 11:12
Posted In: astronomy, tech


Allskypi is an allsky camera system with a ZWO ASI 120MC camera and wide angle lens protruding out into a 4″ transparent dome, with the remainder of the camera and the raspberry pi beneath it in the housing.

The dome was condensing and frosting, so we added a heater inside the dome.

Now the sensor temperatures are higher than we would like, but the condensing and frost problems seem to be fixed.


The holes in the lid were drilled pre-dome-heater, hoping to have hot air from inside the housing rise up into the dome.

Now perhaps the holes are allowing hot air from the domeheater to infiltrate back into the housing and heat up the camera sensor.

I plotted the temperatures of the sensor, air and dew from our nearby weather station and got this below.

So looking at this graph, what more can be done to lower the camera sensor temperature (which causes more hot pixels in a 60 second exposure)?

Idea 1) plug the holes in the lid to stop airflow from dome to housing

Idea 2) add vent holes at the top of the housing, below the lid and dome, to allow hot housing air to escape.

Idea 3) build some kind of airconditioner.. ie a Peltier cooler, to cool air inside the housing.

Idea 4) add a spacer between the bottom of the camera and its mount for better air flow.
Come warmer air temps in the summer, the sensor temp will definitely get too high… already in the last two weeks it has hit 15C!

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