HyperatlasCoregistered Federated Imagery
Roy WilliamsBruce BerrimanGeorge DjorgovskiJohn GoodReagan Moore
Caltech CACRCaltech IPAC
Caltech AstronomyCaltech IPAC
San Diego Supercomputer Center
Image Federation
Multispectral Imagery
Crab Nebula.3 channels: radio in red. optical in green, and X-ray in blue.
Moffet Field California. 224 channels from 400 nm to 2500 nm
2MASS-SDSS fusion
Red at 1.2 um (2MASS J), Green at 0.75 um (SDSS i), Blue at 0.47 um (SDSS g).
Image Federation
detection
Stacking allows detection of faint sources. A 1-sigma detection in each of many bands becomes a 3-sigma detection.
Images of the same galaxy taken several days apart are automatically subtracted from one another, and remaining bright spots may be supernova candidates. (NEAT project)
Image subtraction allows detection of narrow-line features that are not also wide-band (eg Hα but not R-band)
Multiwavelength Sky
• Sociology of EM spectrum• “Xray astronomy”, “Radio astronomy”
• Essentially multiwavelength objects• Can only be seen in different bands• Quasars discovered by Radio/Optical fusion• Gamma ray bursts in Gamma/optical
Time Federation
• Palomar-Quest survey• 50 Gbyte/night to Caltech/Yale• Searching for transients
– asteroids, plutinos
– catalysmic variables
– lensing events (MACHO)
– cataclysmic galaxies
– quasar transients
– Deep catalogs– Average sky– Maximum sky– Time correlated sky (deep periodics)
Atlasmaker:Principle Components
SDSS (5 channel) SDSS+2MASS (8 channel)
ExampleNGC 4125 at 50 Mpc
2MA
SS
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fusion
Images and Pages
Image• Big data
Page• Map: sphere → plane• FITS-WCS header• small data
An atlas is a collection of pagesHyperatlas is an attempt to standardize atlases
HyperatlasStandard naming for atlases and pages
TM-5-SIN-20Page 1589
Standard Scales:scale s means 220-s arcseconds per pixel
SIN projection
TAN projection
TM-5 layout
HV-4 layout
Standard Projections
StandardLayout
Hyperatlas is a Service
All Pages: <baseURL>/getChart?atlas=TM-5-SIN-200 2.77777778E-4 'RA---SIN’ 'DEC--SIN' 0.0 -90.01 2.77777778E-4 'RA---SIN‘ 'DEC--SIN' 0.0 -85.02 2.77777778E-4 'RA---SIN‘ 'DEC--SIN' 36.0 -85.0...17312.77777778E-4 'RA---SIN‘ 'DEC--SIN' 288.0 85.017322.77777778E-4 'RA---SIN‘ 'DEC--SIN' 324.0 85.017332.77777778E-4 'RA---SIN‘ 'DEC--SIN' 0.0 90.0
Best Page: <baseURL>/getChart?atlas=TM-5-SIN-20&RA=182&Dec=621604 2.77777778E-4 'RA---SIN‘ 'DEC--SIN' 184.61538 60.0
Numbered Page: <baseURL>/getChart?atlas=TM-5-SIN-20&page=16041604 2.77777778E-4 'RA---SIN' 'DEC--SIN' 184.61538 60.0
ImplementationsbaseURL = http://mercury.cacr.caltech.edu:8080/hyperatlasbaseURL = http://virtualsky.org/servlet
Various TM Atlases
20 degree
10 degree
5 degree
Various HV Atlases
Google Sky
Renders all data to single CAR (Mercator) projection
-- Good for Jpeg, not for FITS…..
Hyperatlas Services
Questions:Who does resampling of images and why?What science is in images that is not in catalogs?
Hyperatlas Serviceshttp:nvo.caltech.edu:8080/hyperatlas
Transparent Code
int ndec = 1 + (int)(180/delta + 0.5);double ddec = 180.0/(ndec-1);int nra;double dra;for(int i=0; i<ndec; i++){
dec = -90 + i*ddec;
// This prevents gaps in the rings near the polsif(dec<0) dech=dec+0.5*ddec;else dech=dec-0.5*ddec;
nra = (int)((360/delta) * Math.cos(dech*Math.PI/180)) + 1;
if(i==0 || i==ndec-1) nra=1;dra = 360.0/nra;for(int j=0; j<nra; j++){
v = new Vector3d(dra*j, dec);points.addElement(v);
}}
Projects
• 2MASS hyperatlas at SDSC complete• SDSS DR5 starting• Palomar-Quest also building HA• Nesssi services make HA tiles