This repository encloses the data reduction pipeline for the Italian PRISMA fireball network. PRISMA is the First Italian Network for the systematic Surveillance of Meteors and the Atmosphere (in Italian, Prisma Rete Italiana per la Sorveglianza Sistematica di Meteore ed Atmosfera).

PRISMA is a partner of the FRIPON international collaboration. More information about the FRIPON network is available here.

This pipeline handles all the data reduction procedures within the PRISMA network, which are mainly subdivided into the analysis of calibration data (long exposure image to determine the astrometric and photometric reduction of each camera) and meteor videos.

Introduction & Nomenclature

The PRISMA network is made of stations (nodes) consisting of a mini-PC (NUC), a network switch and the fish-eye camera itself. Each node of PRISMA is named by the following FRIPON convention:

• CODE: example ITPI01 (IT = Italia, PI = Piemonte, 01 = progressive number of the station in the region)
• NAME: example PINOTORINESE

FreeTure

PRISMA nodes are operated by an open-source software named FreeTure which handles the data acquisition on each single station and, in particular, the process of meteor detection. The camera acquires a 30 fps video stream that is triggered in livetime by FreeTure looking for meteors in the field of view (FoV).

PRISMA data are divided into two categories: captures (calibration data) and events (meteor data). The structure of these data is detailed in the Workspace page.

Events

Once FreeTure triggers a meteor, a video of few hundred of frames is saved in FITS format. The video of the meteor captured by one node is called detection. The trigger is handled by each node independently. Then, the node interacts with the central server to know if other stations in the network registered a detection at the same time.

An event is made of two or more detections of the same meteor made by different (≥ 2) nodes. The event is named by its date in the following convention: YYYYMMDDTHHMMSS_UT (e.g., 20190415T194950_UT)

Inside the event, each detection is named by adding the station NAME before the date: NAME_YYYYMMDDTHHMMSS_UT (e.g., PINOTORINESE_20190415T194950_UT)

Be aware that the date reported in the detection name might slightly differ (± 5 s) from the event date. This is due to the fact that each station may trigger the same meteor from a different starting time, or nodes may be not perfectly synchronized in time.

Captures

For calibration purposes (both astrometric and photometric) of each station, the 30 fps stream is paused each 10 minutes to acquire a long-exposure image (5 seconds) named capture, also saved as a FITS file by FreeTure. Captures are calibration images which allow detecting stars down to +4/+5 mag (depending on the light pollution of the site).

If the node is fully operative, one should expect ~144 captures / day / station. This is a continuous dataflow from each station, and accounts in reality for most of the disk-space needed for the storage of PRISMA data.

Each capture is named after the station code and the acquisition date-time, in the following convention: CODE_YYYYMMDDTHHMMSS_UT-0.fit (e.g., ITPI01_20180100T001054_UT-0.fit)