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Pleased to announce that our first instalment of DebrisWatch is available online. This is an ongoing collaboration between our team at Warwick and the Defence Science & Technology Laboratory (UK) investigating the population of geosynchronous (GEO) #orbitaldebris 1/ https://twitter.com/WarwickAstro/status/1302950814969933825">https://twitter.com/WarwickAs...
We used the 2.5m Isaac Newton Telescope (INT) to observe the GEO region located roughly 36000km above the equator. The region encompasses the geostationary belt, possessing unique properties that have been exploited for communications since the formative years of the space age 2/
This was the first time the INT had been used to search for artificial objects. Like many of the GEO surveys conducted in the past, we acquired images with the telescope fixed in hour angle and declination (i.e. without tracking) 3/
Astronomical images are usually taken with the telescope tracking at the sidereal rate, so that the stars of interest are point-like despite the Earth& #39;s rotation. In our images, the stars were instead trail-like, while objects of interest would appear as points or short trails 4/
Using a custom pipeline to process the images, we were able to pick out candidate GEO objects and measure their brightness. With the large aperture of the INT, we were able to probe to roughly 21st visual magnitude 5/
To put this into perspective, if we make standard assumptions regarding the shape and reflectivity of the objects, we probe to below 10cm. However, as we& #39;ll see, these assumptions are very uncertain, as we lack a priori knowledge for the majority of detections... 6/
We attempt to match our detections to known objects in the publicly-available USSTRATCOM catalogue, finding that over 80% of detections fainter than 15th visual magnitude failed to match. This is consistent with the roughly 1m cutoff for catalogued objects in GEO 7/
For the orbital tracks detected, we extract measurements of brightness over time. Light curves contain important information about the nature of an object and how it& #39;s behaving. The apparent brightness of an object will depend on its size, shape, orientation, attitude, etc 8/
We find many of our faint detections to be showing signs of tumbling. Some of them straddle the sensitivity limit of the detector; brightness variation of this kind makes it very difficult to estimate an object size, as discussed above 9/
Hopefully that& #39;s provided a quick overview. You can find the manuscript accepted for publication in Advances in Space Research here: https://www.researchgate.net/publication/343745129_DebrisWatch_I_A_survey_of_faint_geosynchronous_debris">https://www.researchgate.net/publicati... if you& #39;d like to know more! 10/
