Autonomous Allsky camera with Raspberry PI. Part 3: shooting night sky in FITS using QHY5-IIM camera

This is a third part of the Allsky cycle.

Please read previous articles to get complete information about this project:

Part 1. Autonomous Allsky camera with Raspberry PI: overview.
Part 2. Autonomous Allsky camera with Raspberry PI: powering and lightning protection

This time I will show my utility and script for shooting night sky and processing of the images.

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Autonomous Allsky camera with Raspberry PI. Part 2: powering and lightning protection

This is a second part of the Allsky cycle and I want to describe powering and protection of this device.

Please read first part to get basic information about this project.

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Autonomous Allsky camera with Raspberry PI. Part 1: overview.

Allsky (or weather) camera is one of the most important part of the modern observatory.
It’s very important to monitor sky condition during night observations, especially when observatory is remote controlled or should be fully automatic. Different vendors provides different solution. But all they are share the same problems: very high prices, lack of autonomy (PC is required) and lack of useful sensors like a temperature, sky temperature and so on. So, to build complete system you need: camera itself, PC, weather station, cloud sensor. Full price and complexity of this system is very high.
But this not a Jedi path, right?
With this article I’m starting the cycle of the materials dedicated to fully autonomous device, based on Raspberry PI. This device contains two cameras and a lot of sensors.

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Connecting HTU21D temperature/humidity sensor to the Raspberry PI using simple C i2c interface

Previously in my projects I’m always used well known DHT22 (AM2302) temperature/humidity sensors. But I found that this sensors is not very stable and subject to hungs. In my case this device is worked about two weeks and then stops responding untill power rebooted. This is absolutely unacceptable on some distant and autonomous devices. After some googling I found that I’m not alone and some peoples also expirienced such problem.
I’ve decided to replace this sensors to something more reliable and more accurate. My choice fell on HTU21D from the Measurement Specialties. HTU21D is a quite reliable and precise sensor, much newer than DHT and uses standard i2c bus instead own 1-wire protocol. I2C interface was a determinative and in this article I want to describe connection of this device to the Raspberry PI in details.

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Connecting MLX90614 infrared thermometer to the Raspberry PI

MLX90614 is a cheap and popular infrared thermometer from Melexis. This device is made in different version for different purposes.
You can get generic purpose version with 0.5 accuracy or for medical purposes with accuracy up to 0.2.

Also you can choose voltage you needed: 3.3v or 5v versions is available.
With MLX90614 you can distantly measure temperature of the objects, even temperature of the sky. This enables a wide range of tasks in science and technics.
In this article i’ll show how to connect this device to the Raspberry PI microcomputer via i2c bus.

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