1. GSCII Project Gauging the quality of the GSCII DB with QA_2plates: First results R. Pannunzio, R. Morbidelli, A Spagna, M. G.Lattanzi

2. Diagram of QA_2plates procedures

3. QA_2Plates First level procedures (connection with CIQA) Procedure nameLevelDescriptionStatus Input_variables Common Allows proper data transfer from the FDB to IDL (required for compatibility with CIQA) Operational Output_variables Common Declares the names of the internal variables used by the QA_2Plates procedures “ “ Define_internal_variables First Generates values for internal variables (defined in Output_variables) from the FDB values read in Input_variables “ “ Evaluate_magnitudes First Computes the magnitude ranges of the measured objects on both plates “ “ Class_index First Generates tables of indices for all combinations among objects with different classification (needed by several procedures that require classification codes) “ “

4. QA_2Plates: s econd level procedures Procedure nameLevelDescriptionStatus Write_reportSecond Write an ASCII report file with relevant statistical information on the given plates Operational ClassesSecond Generates histograms describing the relative (to the overlap plate) performance of the classifier on the source plate as a function of magnitude “ “ Plate_overlap_2platesSecond Graphic representation of the overlap area between the two plates and most relevant information on the plates themselves (location on sky, passband,...) “ “ VectorsSecond Vector representation of mean errors in position as function of position on plate (classification is also considered) “ “ TrendsSecond Plots mean positional and magnitude differences vs magnitude (object classifications also considered) “ “ Deep_histogramsSecond Generates histograms for magnitude and position differences (between the two plates) for all possible classification combinations of the matched objects “ “ Magnitude_histogramsSecond Plots histograms of positional differences as a function of magnitude bins and for all possible classifications cases “ “ Write_reportSecond Calculates and displays histograms of counts of stars, non stars, and defects as a function of magnitude for the two plates. “ “

5. QA_2Plates: Third level procedures Procedure nameLevelDescriptionStatus Make_trends Third Called by the routine TrendsOperational Make_histogram Third Called by Deep_histograms “ “ Make_vectors Third Called by Vectors “ “ Mag_make_histogram Third Called by Magnitude_histograms “ “ Mag _vectors Third Called by Vectors “ “ Write_deep_informations Third Called by Write_report “ “ Other ???…….Called by the routine Trends…………

6. Star counts

7. Magnitude equation

8. D(mag) vs mag

9. Positional error as function of plate position

10. Magnitude error as function of plate position

11. The sample of processed plates NUMBER OF SOURCE PLATES067 NUMBER OF PLATE PAIRS QAed 840 PAIRS OF GSC I-II/GSCII PLTS WITH RELIABLE RESULTS708335 PAIRS OF GSC I-II /GSCII PLTS WITH SAME COL.DIFF.AREA127059 PAIRS OF GSC I-II /GSCII PLTS WITH SAME AREA DIFF.COL.091064 PAIRS OF GSC I-II /GSCII PLTS WITH DIFF.COL.- DIFF.AREA479212 PAIRS OF GSC I-II /GSCII WITH SAME COL. AND SAME AREA011000

12. GALACTIC REPRESENTATION OF THE GSCII PLATES AT OATO Source (+) Overlap ( )

13. Results from GSCII plate pairs STARS-STARS NON STARS - NON STARS      mag      mag  MEAN VAL.GSCII ALL DATA+0.00 +0.55 -0.00 +0.49 +0.01 +0.47 +0.00 +0.72 -0.00 +0.69 +0.01 +0.59  GSCII ALL DATA+0.42 +0.20 +0.23 +0.17 +1.01 +0.20 +0.38 +0.18 +0.19 +0.17 +1.00 +0.23 MEAN VAL. GSCII SAME COL.+0.02 +0.50 -0.00 +0.44 +0.04 +0.27 +0.02 +0.67 -0.01 +0.61 +0.03 +0.32  OF GSCII SAME COL.+0.51 +0.18 +0.22 +0.15 +0.27 +0.08 +0.48 +0.20 +0.26 +0.17 +0.34 +0.12 MEAN VAL.GSCII SAME AREA+0.00 +0.38 +0.00 +0.36 +0.00 +0.54 +0.00 +0.64 +0.00 +0.63 -0.00 +0.61  OF GSCII SAME AREA +0.15 +0.16 +0.17 +0.15 +1.30 +0.20 +0.13 +0.20 +0.15 +0.20 +1.27 +0.18 MEAN VAL.GSCII DIFF.AREA - COL+0.00 +0.61 -0.00 +0.54 -0.00 +0.51 +0.00 +0.76 -0.00 +0.72 +0.00 +0.65  OF GSCII DIFF. AREA - COL.+0.44 +0.17 +0.24 +0.16 +1.04 +0.19 +0.39 +0.15 +0.19 +0.16 +1.03 +0.20

14. Results of generic pair of plates  0 – 0  3 – 3  MEAN of ALL GSCII PAIRS +0.00  of ALL GSCII PAIRS +0.42+0.38 MEAN of PAIRS WITH SAME COLOR +0.02  of PAIRS WITH SAME COLOR +0.51+0.48 MEAN of PAIRS WITH SAME AREA +0.00  of PAIRS WITH SAME AREA +0.15+0.13 MEAN of PAIRS WITH DIFF. AREA AND COLOR +0.00  of PLTS WITH DIFF. AREA AND COLOR +0.44+0.39

15. Percentage of outliers

16. Comparison GSCI + GSCII and GSCII plates (  case ) stars – stars

17. Comparison GSCI + GSCII and GSCII plates (  case ) stars – stars

18. Comparison GSCI + GSCII and GSCII plates (  case ) nostars – nostars

19. Comparison GSCII plates (  case ) stars/stars and non stars/non stars

20. Comparison GSCII (  ) star-star case

21. Comparison GSCII (  ) non star-non star case

22. Comparison GSCII (  ) star-star case, same color

23. Comparison GSCII (  ) star/star and non-star/non-star case same color

24. Comparison GSCII (  ) star/star case same area/diff. color and same color/diff. area

25. Comparison GSCII (  ) non-star/non-star case same area/diff. color and same color/diff. area

26. Comparison GSCII (  ) star/star and non-star/non-star same area/diff. color

27. Comparison GSCI + GSCII and GSCII plates (  magnitude) star–star

28. Comparison GSCI + GSCII and GSCII plates (  magnitude) non-star/non-star

29. Comparison GSCII plates (  magnitude) star/star and non-star/non-star

30. Comparison GSCII (  mag.) star/star case same color/diff. area and same area/diff. color

31. Comparison GSCII (  mag.) non-stars/non-stars case same color/diff. area and same area/diff. color

32. Comparison GSCII plates(  mag ) star/star and non-star/non-star same color – diff. area

33. Comparison GSCII plates(  mag ) star/star and non-star/non-star diff. color – same area

34. Comparison GSCII plates(  ) star/star and non-star/non-star

35. Comparison GSCII plates (  and  ) star/star

36. Comparison GSCII plates(  ) star/star and non-star/non-star same color and different area

37. Comparison GSCII plates(  ) star/star and non-star/non-star different color and same area

38. Comparison GSCII plates(  ) star/star diff. color/same area and same color/diff. area

39. Comparison GSCII plates(  ) non-star/non-star diff. color/same area and same color/diff. area

40. Comparison GSCII plates(  mag ) star/star and non-star/non-star

41. Comparison GSCII plates(  mag ) star/star same color/diff. area – diff. Color/same area

42. Comparison GSCII plates(  mag ) non-star/non-star same color/diff. area – diff. Color/same area

43. 1.THIS IS A FIRST SYSTEMATIC ASSESSMENT OF GSCII DATA QUALITY BASED ON A LIMITED NUMBER OF PLATES. THESE ARE DISTRIBUTED AROUND THE GALACTIC PLANE AND THE GALACTIC POLES. 2.AS EXPECTED, THE ASTROMETRY IN BOTH COORDINATES IS BETTER FOR THE STAR/STAR CASES THAN FOR THE NON-STAR/NON-STAR ONES 3.THE  (  ) IS ON AVERAGE BETTER THAN  (  ) IRRESPECTIVE OF CLASSIFICATION 4.THE ASTROMETRY IS GENERALLY BETTER FOR PLATE PAIRS HAVING SAME AREA AND DIFFERENT COLOR IRRESPECTIVE OF OBJECT CLASSIFICATION 5.THE PHOTOMETRY APPEARS VERY CONSISTENT IRRESPECTIVE OF CLASSIFICATION. ON PAIRS OF EQUAL-BANDPASS PLATES THE AVERAGE ERROR (IN THE DIFFERENCE) IS ~0.3 MAG Summary Notes

44. Summary Notes (continues) 6.AS EXPECTED, THE MEAN VALUES IN ,  AND (  mag) ARE CENTERED AROUND THE NULL VALUE 7.MORE INTERESTING, THE DEVIATIONS OF ,  AND (  mag) FROM THEIR MEAN VALUES SHOW THE EXPECTED BEHAVIORS FOR THE DIFFRENT CLASSES OF PLATE PAIRS (SAME AREA, DIFFERENT AREA, SAME BANDPASS, DIFF. BANDPASS, ETC.) 8.THIS GLOBAL QA DOES ALLOW THE DETECTION OF ANOMALOUS PLATES, AS IT WAS THE CASE FOR G039 (S020) 9.THIS TYPE OF ANALYSIS NEEDS TO BE RE-RUN ON A REPRESENTATIVE SET OF PLATES IN THE PRODUCTION DB AT ST ScI

45. First comparison to 2Mass The following figure shows the results of matching GSC2.1.1 data to the 2MASS catalog. The area matched is approximately 30 arcmin in radius and corresponds to a region close to the lower edge of a second generation survey plate. The left panels show the one-dimensional residuals as function of magnitude for the two bandpasses J and F. The rightmost panels show the residuals in distance. Averaging over the whole magnitude range provided the following results: 0.3 +/- 0.5 in RA (on the sky) and 0.5 +/- 0.13 in DEC.

46. First comparison to 2MASS data