"Een nieuwe blik op sterrenkunde"

"Panoramische camera's en het Astro-Wise systeem"

Gijs Verdoes Kleijn

Kapteyn Astronomical Institute, University of Groningen

Human vision: data load

• Eye: – resolution ~5/60deg– Field of view 90^2deg– 2x2 pixel sampling per resolution element – Pixels: 2160^2– Dynamic range: 1e3-1e5: 2^16– One image ~9Mbyte– One image/sec for 70years: 18Pbyte– Costs 18Pbyte (0.33euro/Gbyte)~ 6million euro

Brain does something smart…….

Astronomical vision: data load

• Camera on telescope: – Resolution through atmosphere ~1/3600deg (atmospheric

blurring)– Whole sky: 41e3 deg^2– 2x2 pixel sampling per resolution– Pixels: ~(1.5e6)^2 – Dynamic range: 2^16– One image full sky: 4Tbyte– One full sky/sec for 70years: 8.4e6 Pbyte (was 18Pbyte for eye)– Further data increasing ’ factors: HST 1/10 of atmospheric

resolution; time-resolution; wavelength resolution– Data decreasing factor: depending on depth of exposure: lots of

dark area

Something smart to deal with large datasets is crucial!

The history of the Universe

The big questions (according to me)• Dark matter/energy: (In what form/Where) is ~90% of the

matter? What is dark energy?• Structure formation: how do objects exactly form?

Structure

Galaxy ClustersGalaxies

Black holesStars

Planetary systems

Cooling

Expansion

+Gravity

Collapse

Astronomical science which uses large-area imaging

because it is• Needle in the hay-stack objects• Subtle effects requiring large number statistics

Galaxy clusters PlanetsSupernovaQuasars & Gamma Ray Bursts

AsteroidsLensing

The OmegaCAM panoramic camera

• 16k x 16k mosaic of 32 CCDS: – Each CCD 2k x4k

• Field of view: 1deg^2• pixel size 0.21 arcsec / 15μm. • 330 to 1000 nm • Starting operations end 2006

USM

Padova

1deg

1deg

HST

VLT Survey Telescope (VST) at Paranal, Chile

Artist’s impression

Very Large Telescope (VLT) VLT Survey Telescope (VST)

OmegaCAM vision: data load

Vast amount of data• Single image 550 Mbyte (~200 screens

for full resolution) • Sole instrument: OmegaCAM

observes equivalent of Southern sky in ~3 years (30 min exp, 300 nights/year)

• Many filters & science programs• Of order 10 Tbyte of raw

data/year with time-varying atmosphere, instrument & telescope performance

Vast amount of data• Single image 550 Mbyte (~200 screens

for full resolution) • Sole instrument: OmegaCAM

observes equivalent of Southern sky in ~3 years (30 min exp, 300 nights/year)

• Many filters & science programs• Of order 10 Tbyte of raw

data/year with time-varying atmosphere, instrument & telescope performance

Panoramic image processing and analysis: the classical way

• Image cleaning of instrumental effects– examples: varying pixel sensitivities; cosmic

rays; image distorsions; correction for extinction of light (in atmosphere and

instrument)•

• Derivation of astronomical parameters– examples: size galaxy, color star, brightness

supernova

• Analysis of results– Comparison to theory; statistics

• Image cleaning of instrumental effects– examples: varying pixel sensitivities; cosmic

rays; image distorsions; correction for extinction of light (in atmosphere and

instrument)•

• Derivation of astronomical parameters– examples: size galaxy, color star, brightness

supernova

• Analysis of results– Comparison to theory; statistics

Panoramic image processing and analysis: the Astro-Wise way

• Image cleaning of instrumental effects– examples: varying pixel sensitivities; cosmic

rays; image distorsions; correction for extinction of light (in atmosphere and

instrument)

• Derivation of astronomical parameters– examples: size galaxy, color star, brightness

supernova

• Analysis of results– Comparison to theory; use statistics

• Image cleaning of instrumental effects– examples: varying pixel sensitivities; cosmic

rays; image distorsions; correction for extinction of light (in atmosphere and

instrument)

• Derivation of astronomical parameters– examples: size galaxy, color star, brightness

supernova

• Analysis of results– Comparison to theory; use statistics

Databas

e

The architecture of the Astro-Wise system

Parallel Computing

DatabaseAll OmegaCam

images

Astro-Wise is on-line: you can use it whenever there is internet

www.astro-wise.org/portal

An test-case of Astro-Wise system use

Asteroids

10000

Ecliptic~plane in which planets move

Observations

Asteroids on images• Cross-correlating >3e5 known asteroids with

images:– Code: PyEphem+Astro-Wise – (~1day on Linux box)

• Analysis is student project

To take advantage of state-of-the-art technology to better understand how the Universe came about and evolved you need a team of :

1deg

1deg

HST

-experts

-experts

-experts

-experts

To take advantage of state-of-the-art technology to better understand how the Universe came about and evolved you need a team of :

1deg

1deg

HST

-experts

-experts

OmegaCEN at the Kapteyn Astronomical InstituteOmegaCEN director: professor Edwin Valentijn

Contacts for more info:

• Astro-Wise, OmegaCEN– Gijs Verdoes Kleijn

• Astronomy at RUG in general:– Student advisor: Leon Koopmans– Education advisor: Greta de Vries