Allsky camera, Astro tools, Electronics

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…

Continue Reading

Linux system development

Simple Linux character device driver.

Character device is a one of the simplest way to communicate with module in the Linux kernel. This devices are presented as special files in a /dev directory and supports direct reading and writing of any data, byte by byte, like a stream. Actually most of the pseudo-devices in /dev is a character devices: serial ports, modems, sound and video…

Continue Reading

Allsky camera, Electronics, Linux system development

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…

Continue Reading

Astro tools, Electronics

Isolated eqmod adapter for the telescope control

There are popular and quite cheap amateur telescope mounts from different vendors: Sky-Watcher, Celestron and so on. Most of that mounts contains motors and some controller schematic. User can control this devices in different ways. One way is to use mount’s handcontroller, other way is connect to computer and use some software to control and guide the telescope. Such connection…

Continue Reading

Radio & antennas

144 MHz Yagi-Uda antenna

Yagiā€“Uda antenna is a directional and pretty effective antenna consisting of multiple parallel elements in a line, usually half-wave dipoles made of metal rods. Best-known use of this type of antenna is as rooftop terrestrial television antennas, but it is also used for point-to-point fixed communication links and for long distance shortwave communication by shortwave broadcasting stations and radio amateurs.…

Continue Reading

Astro tools, Software

Converting DSLR RAW images into scientific FITS format. Part 1: UI

FITS – is an open standard defining a digital file format useful for storage, transmission and processing of scientific and other images. FITS is the most commonly used digital file format in astronomy. Unlike many image formats, FITS is designed specifically for scientific data and hence includes many provisions for describing photometric and spatial calibration information, together with image origin…

Continue Reading