CASB Report August, 2001

 

Highlights for Division Meeting

·         A paper on a high-velocity black hole companion by R. P. Mignani, F. Guglielmetti, and their co-authors has been accepted by Nature for publication in the September 13 issue.  The report is based, in part, on GSC-II data.

·         Enhanced the hand-classification software to generate a training set that is measurably more representative of the real objects being classified.

 

Community Affairs and Communications

·         Hosted several tours of the plate vault and scanning facility including flight directors from JSC.

 

Project Management and Technical Infrastructure

·         CASB sends best wishes to members of its staff who are departing or transitioning. 

o        Gretchen Greene will increase fraction of time matrixed to the Independent Detector Testing Laboratory.

o        Fabrizia Guglielmetti will resume graduate studies and perform research on the ROSAT All-Sky Survey at the International Max-Plank Research School for Astrophysics in September.

o        Vicki Laidler is in transition to the ESS Science Software Group.

o        Jane Morrison is assuming a position at the Steward Observatory, University of Arizona, in October.

o        David Wolfe has joined the ESS Data Systems Team and is matrixed with CASB.

·         Ricky Smart (OATo) and Tiziana Franconieri (student in Multimedia Arts and Performance at Torino University) are visiting.  They have prepared a demo CD-ROM presenting an introduction to GSC-II that is suitable for a general audience.  CASB staff are providing additional material for the CD-ROM.

·         McLean and Greene continued supporting SDSS planning activities.

 

MISSION SUPPORT

HST Operations

·         Reviewed ten Guide Star Problem Reports (GSPRs) this period.  All the GSPRs were fine lock failures.  Filed a Bad GS Alert for each of the GSs.

·         Work is continuing on the Bright Object Tool in the VTT with the next release scheduled in the December timeframe.

 

NGST Development Studies

·         No activity

 

DIGITIZED SKY SURVEY

Plate Scanning

·         Continued scanning POSSI-O plates until the latest shipment of UKST-IR plates were available.  Scanned the UKST-IR plates the rest of the period.

 

GAMMA Microdensitometer Systems

·         Gamma 1 continues to perform well. 

·         Several attempts were made to diagnose the continuing problems with GAMMA2.  No conclusive answers have yet been found.

 

Data Compression/CD Production

·         Continued compressing scans of the POSSII-N survey.

·         Continued compressing scans of the POSSI-O survey.

 

Archive Maintenance

·         Continued planning for porting the GetImage software from VMS to NT.

·         Began migration of DSS1 from CDROM to online network storage..

·         Worked on three archive help desk requests for help/information.

·         Continued low-level rationalization of MOD archive.

 

GSC-II

 

Plate Processing and COMPASS Database

·         The GSCII database server, COMPASS, has been upgraded to Windows 2000 as well as a new version of Objectivity (6.1).  New hard disk storage (1.6TB RAID 5) was also added.

·         Planned a new database file structure and started its implementation. This should allow maximum efficiency of the new disk storage.  The file moves are going well and should be completed very shortly.

·         (OATo) Developed tools for plotting all-sky high-resolution maps of the GSC2 objects.  These can be useful for the detection of plates affected by various kinds of problems.

·         (OATo) Performed comparisons between GSC2 photometry and deep CCD catalogs. Typical errors of 0.1-0.3 mag are found.

·         (OATo) Comparisons between GSC2.2 and UCAC/2MASS give indications that the decision to select objects nearest to the plate center has reduced the effect of magnitude terms in producing systematic errors.

 

CALIBRATIONS: General

 

CALIBRATIONS: Astrometry

·         Working on understanding the systematic errors in GSC 2 positions, which are a function of magnitude and distance from the center of the plate. Using the SPM to quantify the effect.

 

CALIBRATIONS: Classification

·         Modified the XSPAM hand classification tool, hcl_mark, to select objects for hand classification based on their distance from the domain occupied by existing training set objects. For the first time, we have an approach to building training sets that is directed toward a specific and measurable goal. Adding training set objects in this way will extend the domain of the training set to occupy more of the space occupied by real objects – thus producing a more representative training set. This approach also permits the human classifier to better concentrate on the actual task of visual classification, by freeing her or him from most of the decision making over which objects to examine.

·         Created a new training set construction task, VERTRAIN, as part of the VERCLASS package. When run over an OOP file that contains hand-classified objects, it produces a FITS file containing a training set with ranked features and identifying information. This FITS file can be used by OC1 to generate a decision tree. This eliminates the need to run classify in a special "training" mode, creating a temporary OOP file for each plate with ranked values overwritten in place of raw values.  Although this task (still in development) requires a few more capabilities in order to be practically useful, it is the last missing link in the suite of software tools required to manage training sets and decision trees in a sensible way.

·         Continued modifications to VERCLASS, the versatile classification task presently in development.  The voting procedure has been modified to use the object’s distance from the training set domain for a given tree in weighting its vote.  Experiments comparing the results of weighted voting from all-tree voting indicate that that this change in voting procedure, while still affecting only 1-3% of the objects, produces changed classifications that are correct in 70-80% of the cases: a clear improvement.

·         Wrote an XSPAM utility, distance_distribution.pro, to assist in tuning the weighting function, which is an exponential of the form exp(-D/scale). It produces plots showing the distribution of training set domain distances, and up to two possible weighting functions, for each of the five trees. Experiments indicate that a scale factor of 0.017 is reasonable for most plates; 25um scans are the notable exception. This utility will need to be rerun, and the scaling factor retuned, whenever a new set of decision trees is introduced.

·         Implemented an algorithm to define the classification unreliability in VERCLASS. This value is defined to range from 0 to 1, where 0 is reliable and 1 is unreliable. Presently, the distance from the training set domain, and the weighted number of voters, are combined to produce this value. A document that discusses the unreliability in detail has been drafted. The contribution of the number of voters requires some further analysis.

·         A small bug due to rounding error was detected in VERCLASS. Very occasionally, the ranked value (defined in the range {0,1}) of a feature for a given object will be computed to be greater than 1 by about 1e-6. This occurs when the ranked value is averaged across neighboring regions. A workaround was implemented in the tree domain code, which was otherwise excluding objects whose ranked integrated density was greater than one.

 

 

CALIBRATIONS: Photometry (GSPC-II and DSS-I and -II)

·         After reducing the data from La Palma Run 5 (June 23 to July 1) we found nights 1,3,7 and 9 to be photometric quality. The data included 15 POSS-I, 16 POSS-II, and 4 southern sequences.

 

GSC-II Science

·         A paper on a high-velocity black hole companion by R. P. Mignani, F. Guglielmetti, and their co-authors has been accepted by Nature for publication in the September 13 issue.  The report is based, in part, on GSC-II data.  The proper motion result is comparable to that obtained with the VLBA.

·         (OATo) White Dwarfs project:  processed six new fields in the summer sky and got a new list of candidates. Observed one of these targets on August 14 at TNG (La Palma); the reduction is in progress.

·         (OATo)  Preparing a paper about the rare C dwarf star that was serendipitously discovered during the WD search last spring.


 

Appendix – CASB Statistical Summary

 

SCANNING                                                                                                                                                                         

Survey

Goal

Previous Month

Current Month

Current Total

%

done

Notes

Priority

POSS-II J

897

902

0

902

   100 

         S4

1

POSS-II F

897

910

0

910

100

         S4

1

POSS-II N

897

880

0

880

98

         S4

1

AAO-SES

606

614

0

614

100

         S4

1

PPARC-ER

288

288

0

288

100

 

1

AAO-SR

118

118

0

118

100

S2

-

UKST-SR

112

50

0

50

45

S5

3

UKST-IR

894

697

36

733

82

         S6

2

SERC-J/EJ

447

443

0

443

99

      S1

           2

POSS-I E

106

106

0

106

     100

         S3

           3

POSS-I O

936

354

5

359

38

 

3

Rescans

 

34

0

34

 

 

 

 

COMPRESSION

Survey

Goal

Previous Month

Current Month

Current Total

% done

Notes

Priority

POSS-II J

897

895

0

897

100

 

           2

POSS-II F

897

897

0

897

100

 

1

POSS-II N

897

681

39

720

80

 

3

AAO SES

606

606

0

606

100

 

1

PPARC ER

288

288

0

288

100

 

1

AAO-SR

118

118

0

118

100

 

3

UKST-IR

894

697

0

697

78

 

3

POSS-I O

936

20

28

48

5

 

3

 


 

 

 

MO DISK ARCHIVING

Survey

Goal

Previous Month

Current Month

Current Total

% done

Notes

Priority

POSS-II J

897

902

0

902

100

 

4

POSS-II F

897

900

0

900

100

 

3

POSS-II N

897

833

0

833

93

 

           4

AAO-SES

606

613

0

613

100

 

3

PPARC-ER

288

288

0

288

100

 

3

AAO-SR

109

116

0

116

100

 

4

UKST-IR

894

697

0

697

78

 

5

SERC-J/EJ

894

892

0

892

100

 

 

SERC-J/REPAIR

48

48

0

48

100

 

 

SERC-J/15mu

449

449

0

449

100

 

5

POSS-I E

933

928

0

928

99

 

2

POSS-I REPAIR

198

198

0

198

100

 

2

POSS-I O

936

20

50

70

7

 

5

POSS-QV

613

613

0

613

100

 

-

SERC-QV

94

94

0

94

100

 

-

GPO/BB

88

88

0

88

100

 

-

 

 

 

 

 

 

 

 

 

GSC-II PLATE PROCESSING

Survey

Goal

Previous Month

Current Month

Current Total

% done

Notes

Priority

POSS-I E

936

931

0

931

99

 

3

POSS-QV

613

2

0

2

0

 

3

POSS-II J

897

897

0

897

100

 

1

POSS-II F

897

897

0

897

100

 

1

POSS-II N

897

232

76

         308

34

 

4

SERC-J/EJ 

     894

829

0

829

93

 

1

South-F

894

894

0

894

100

 

1

UKST-IR

894

168

66

234

26

 

4

South-SR

116

116

0

116

100

 

2

South-QV

94

94

0

94

100

 

2

 

 

GSC-II COMPASS DATABASE LOAD (no.objects = 998,402,801)

Survey

Goal

Previous Month

Current Month

Current Total

% done

Notes

Priority

POSS-I E

936

23

0

23

2

 

3

POSS-QV

613

2

0

2

0

 

3

POSS-II J

897

897

0

897

100

 

1

POSS-II F

897

899

0

899

100

 

1

POSS-II N

897

27

0

27

3

 

4

SERC-J

894

709

0

709

79

 

1

South-F

894

742

0

742

83

 

1

UKST-IR

894

2

0

2

0

 

4

South-SR

116

116

0

116

100

 

2

South-QV

94

90

0

90

96

 

2

 


 

 

GSPC-II OBSERVATIONS

Survey

Goal

Previous Month

Current Month

Current Total

% done

Notes

Priority

POSS-I

584

588

15

603

100

P1

1

POSS-II

314

255

16

271

86

 

1

SERC

894

885

4

889

99

 

1

 

GSPC-II REDUCTIONS

Survey

Goal

Previous Month

Current Month

Current Total

% done

Notes

Priority

POSS-I

584

588

15

603

100

P1

1

POSS-II

314

255

16

271

86

 

1

SERC

894

902

4

905

100

 

1