Video detection of meteorites and fireballs

The objective of the project is to build a video capture station of meteorites and fireballs for the observatory.

The elements of the system are basically:

  • High sensitivity CCTV camera

  • CCTV lens

  • Video capture, to obtain the composite video signal from a PC through USB

  • 12VDC source to power the camera

  • Twilight detector

  • Weatherproof housing.

Camera

Watec 902H, very compact device with analog output on composite video, high sensitivity, 12V power supply, 1/2" sensor, connector for CS mount lenses. The camera was purchased by eBay at a very good price (about $ 60). The operation is correct although many "hot pixels", of the order of 40, can be seen in the night images. This disfigures the images and makes it difficult to differentiate the true stars but does not affect the recording of the meteorite videos.

Lens

After performing several tests, an 8mm lens has been chosen that provides a field of about 30º and allows to see stars from approximately the fourth magnitude, which gives us a good sensitivity for the purpose of meteorites and fireballs.

 

Video grabber

EZCAP has been selected for its price (around € 15) and driver compatibility.

Power supply

Among the sources of 12V that accumulated from unused equipment, I selected a source that would allow to exchange the type of plug, with the idea of ​​installing it without plug and solder directly to the interchangeable connector the network cable.

Twilight detector

It allows to keep the camera off during the day to avoid damaging the sensor due to the incidence of sunlight. If the camera is to be used only as a night camera, it is advisable to turn it on only at night, and the twilight light detector is a simple and economical solution (less than € 30).

Weatherproof housing

There are many options to intergrate all the elements (camera, source and twilight detector) in a weatherproof housing. In my case, I took advantage of a housing of a damaged outdoor dome camera to carry out the assembly.

The camera has been fixed in a profile so that it has the possibility of adjusting the altitude.

In the photo you can see the power supply on the right, and the twilight detector on the left.

The crepuscular detector has been cut some unnecessary plastic parts to reduce the size and get the photoelectric cell visible from the outside and therefore receive light when it is day.

Detail of the support in which an L-piece has been used and fixed by means of a camera fixing accessory that usually comes between GoPro-type camera accessories.

Detail of the power supply with interchangeable plug, which has been removed from the plug and soldered directly the network cable, then protected by a heat-sealing gun.

Detail of the twilight detector where the position in which the photoelectric cell is located can be seen.

The equipment was installed in a window facing south, near the PC. It was fixed with a drill in the center, so that you can easily adjust the desired azimuth. The altitude was set at about 40º in order to avoid the buildings in front of the window, although it is also adjustable by removing the transparent plastic dome.

Software

The software selected for the video capture is UFOCapture, program of detection and recording of movement from the video of the camera very easy and intuitive to use, and at the same time very complete in the parameters that allow to configure the detection intervals (I have it configured depending on the ortho and sunset), sensitivity, duration, speed, and other variables that allow to discriminate the type of events that you want to capture.

UFOCapture can be downloaded and used free of charge for a month and after that it is necessary to buy a license that is around € 200.

In the capture of the software the trace of a meterito is shown. The image generated by the program helps to distinguish the type of event captured, although logically it also records the video corresponding to this trace.

The small squares of the image are the hot pixels, which in the trace are indicated because they have been configured as a mask in order to better differentiate the stars of truth from the false stars that generate these points in the image.