https://wiki.dfn.net.au/index.php?title=Finding_Fireballs&feed=atom&action=historyFinding Fireballs - Revision history2024-03-29T07:05:53ZRevision history for this page on the wikiMediaWiki 1.30.2https://wiki.dfn.net.au/index.php?title=Finding_Fireballs&diff=37&oldid=prevRobert Howie: 1 revision imported2018-08-23T17:54:25Z<p>1 revision imported</p>
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</td></tr></table>Robert Howiehttps://wiki.dfn.net.au/index.php?title=Finding_Fireballs&diff=36&oldid=prevRobert Howie: 1 revision imported2018-08-17T12:01:27Z<p>1 revision imported</p>
<p><b>New page</b></p><div>This page will contain instructions for<br />
* recognising fireballs from satellites and other night-time phenomena<br />
* downloading and viewing images from DFN observatories<br />
* processing event detection emails<br />
* initiating the data processing pipeline for triangulation and orbits<br />
<br />
=== Automated software for detecting fireballs ===<br />
The images are automatically processed on the cameras.<br />
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The software basically works be differencing consecutive images, and tries to identify lines in the pictures.<br />
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That means that it is unable to tell apart fireballs from satellites or planes.<br />
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The software logs in a file called YYYY-MM-DD_DFNXXXNNN__log_processing.txt.<br />
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In addition, each detection generates several files:<br />
* .tile.jpg : light weight compressed JPG cut-out of the detection<br />
* .pixels.txt : rough pixel coordinates of the event<br />
* .raw_pixels.txt<br />
* .radec.txt : rough astrometric coordinates of the event<br />
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=== Central server vetting ===<br />
As mentioned above, the results of the fireball detection software contain numerous false alerts (satellites, planes...), therefore the candidate events are vetted by a rough triangulation with other cameras.<br />
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=== Email alerts for human review ===<br />
Emails are sent only when a triangulation is validated by the central server.<br />
==== Valid detections ====<br />
Each email is the result of a valid triangulation between 2 cameras detected by the server. This means that if more than 2 cameras detected the event, there are going to be one email for each pair of cameras.<br />
[[File:005 2017-07-31 115327 E DSC 0401.thumb.5200.3600.tile.jpg|left|thumb|'''Fireball'''. Typical (relatively faint) fireball. Shutter breaks are clearly visible.]]<br />
[[File:12 2017-06-30 142632 S DSC 3018.thumb.masked.overkill.1200.400.tile.jpg|thumb|'''Fireball'''. Very bright fireball observed from a large distance. At first look shutter breaks are hard to resolve, but this is indeed a fireball.]]<br />
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==== False positives ====<br />
[[File:Satellite detected by a DFN camera.jpg|thumb|'''Satellite'''. The shutter breaks are hard to resolve because the apparent angular speed is much lower than that of a fireball.]]<br />
[[File:17 2017-08-10 105313 S DSC 0174.thumb.masked.6000.3200.tile.jpg|left|thumb|'''Plane'''. Low flying planes have a similar angular speed as fireballs. It is impossible to tell them apart just by looking at a tile. Planes will typically be visible on several consecutive images, and can manoeuvre.]]</div>Robert Howie