24 maja 2007Joanna Falzmann Algorithm for automatic estimation of measurements quality 1 Pi of the Sky Algorithm for automatic estimation of quality of measurements Joanna Falzmann UKSW

24 maja 2007Joanna Falzmann Algorithm for automatic estimation of measurements quality2 Pi of the Sky  Searching for optical flashes of astronomical origin  Every night thousands of pictures (frames) are taken  All data goes to the huge database  Part of this data has low quality. It’s caused by clouds, full moon…

24 maja 2007Joanna Falzmann Algorithm for automatic estimation of measurements quality3 Division into fields   Sky has been divided into fields   Astronomical coordinates gives name for each field (Right Ascention and Declination)   Example: Ra= 08h 00m Dec=20   600 fields in database   About 500 was observed at least once

24 maja 2007Joanna Falzmann Algorithm for automatic estimation of measurements quality4 Number of visible stars   Each field has characteristic number of stars on it   If we know this number we can use it for estimation of quality of fames   Plot of the number of stars on each field is automatically created every night

24 maja 2007Joanna Falzmann Algorithm for automatic estimation of measurements quality5 Clouds and High Moon Clouds Sun sets Good data Sun raises

24 maja 2007Joanna Falzmann Algorithm for automatic estimation of measurements quality6 Example of good data Good data Sun sets Good data Sun raises

24 maja 2007Joanna Falzmann Algorithm for automatic estimation of measurements quality7 Clouds and High Moon  System sees less stars that it is there  We need to build an automatic tool to select bad and good frames  Associate a „quality measure” to each frame

24 maja 2007Joanna Falzmann Algorithm for automatic estimation of measurements quality8 Building an algorithm   Finding all interesting data for each field   Number of measurements greater than 10   Creating histograms for all fields fo all nights   Analizing the histograms   Inserting characteristic number of stars to database

24 maja 2007Joanna Falzmann Algorithm for automatic estimation of measurements quality9 Histograms   Some histograms are regular – we can fit one gauss

24 maja 2007Joanna Falzmann Algorithm for automatic estimation of measurements quality10 Histograms – one gauss

24 maja 2007Joanna Falzmann Algorithm for automatic estimation of measurements quality11 Information to the database   About 50 fields in 500 of all has this regularity   Info about mean value and sigma to the database

24 maja 2007Joanna Falzmann Algorithm for automatic estimation of measurements quality12 Histograms – two gausses   Some histograms show two gausses

24 maja 2007Joanna Falzmann Algorithm for automatic estimation of measurements quality13 Histograms – two gausses

24 maja 2007Joanna Falzmann Algorithm for automatic estimation of measurements quality14 Strange events

24 maja 2007Joanna Falzmann Algorithm for automatic estimation of measurements quality15 Investigation   Histograms of about 150 fields in 500 of all are useless   We need to collect more data   For the rest we have to investigate why they have two (or more) gausses structure

24 maja 2007Joanna Falzmann Algorithm for automatic estimation of measurements quality16 Criteria   Changing criteria   More than 30 measurements of the field during one night   Cut observations from begin and end of the night   Cut measurements with full moon

24 maja 2007Joanna Falzmann Algorithm for automatic estimation of measurements quality17 Implementation  Sipmle algorithm wich will give number for each frame:  Frames with number of stars equal mean value - sigma – very good  Frames with mean value – 1 to 2.5 sigma – acceptable, but suspicious  Discard the rest