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

• S1. Low priority program to rescan crowded fields (|b|<30) originally done with 25 mu scans. The total number of S scans includes the 2 for the LMC and SMC plus 4 others with |b|>30 performed for research or STIS BOP support. Another 30 plates have been added to replace those that were repaired before inclusion in DSS-I.
• S2. This survey is an on-going low level-of-effort collaboration between the STScI and the AAO.
• S3. Low priority scans of the POSS-I -24 deg and -30 deg zones.
• S4. Includes recent scans of better grade plates.
• S5. Low priority scans of the moderately short exposure R plates from the SERC I/SR Atlas of the Milky Way.
• S6. Includes UKST-IR plates from the SERC I/SR Atlas of the Milky Way and the Magellanic Clouds (1978-1985) and the I-Survey of the Southern Sky (1990-xx).

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

• P1. The current totals have been revised from earlier ones.