Upgrade plan of the MOA 1.8-m telescope

F. Abe

MOA collaboration

19 Jan. 2009, 13th Microlensing Workshop @ Paris

Discovery of Neptune

• In 1846, a mathematician of Observatoire de Paris, Le Verrier predicted a new planet

• Independent prediction was made by Adams, UK

• Then, Neptune was discovered by Galle at Berliner Sternwarte as per their predictions

Urbain Jean Joseph Le Verrier

John Couch Adams

Predictions were essential

Discovery of OGLE 2005-BLG-390Lb

Beauliu, et al., 2006

Unpredictable

Discovery of MOA 2007-BLG-192Lb

Bennett, et al., 2007

Single lens light curve

MOA high-cadence observations

OGLE observations

Real time　 detection of anomalyOGLE 2007-BLG-368/MOA 2007-BLG-308

Sumi, et al., this WS

Short timescale events(MOA 2006-BLG-98)

Kamiya, et al., this WS

tE ~ 1day

Caused by very low-mass star(?):Free-floating planets (?)Brown dwarfs (?)

Current MOA telescope & CCD Camera

• Installed at Mt. John, Observatory, NZ in 2004

• Aperture: 1.8 m• FOV: 2.18

degree^2• Seeing > 1.5”• 1 observation/hour

4 corrector lenses2 degree image circle

Plan of upgrade to get wider FOV

Sako et al., 2008

Optical design (by A. Rakich): Requirements & compromise

• Requirements– FOV: as wide as possible– Primary mirror: use present mirror– No aspheric lens– No special low-dispersion glasses

• Compromise– Replace corrector lenses– Throw out short wavelength (U, B)– Circular effective area

New corrector lenses (4 degree)

By A. Rakich

f/2.964 deg~ 12 deg^2

f/2.912 deg.

BK7BK7 BK7 BK7 BK7

FQ

Vessel Window

3-4 layer coating

All spherical surfaces

Spot diagram (I)

30μm ~ 1.16”

4degreeImage circle~12deg^2

Spot diagram (V)

Target FOV: ~ 10 deg^2

Possible CCD layout

Image circle4 degree in diameter

CCD chip3cm x 6cm0.33°x 0.66°

Total: 52 chips11.3 deg^2

5-6 observations/hourFactor 5 improvement

Honeycomb scan

Honeycomb survey (example)

1 2 3

6 45

7 8 9

Seamless survey can be made without overlap

CCD chips & Electronics

• Current CCDs– E2V CCD4882– 2k X 4k, 3cm x 6cm– Back illuminated– QE: > 90% (500nm), ~30%

(900nm)

• Astronomical Research Camera Gen III

• Hamamatsu CCDs– S10892-01– 2k X 4k, 3cm X 6cm– Back illuminated, 　 full de

pletion (developed by LBNL)

– QE: ~90% (600-850nm) >80% (900

nm)– Factor 2 improvement

• Astronomical Research Camera Gen III

for SUBARU HSC

Time schedule

R&D, cost estimate

Proposal

Lenses

Observations

2009 2010 2011 2012

Oct 30 Apr 1

Camera

Blanks

CCDsetc.

Polishassemble

AssembleTests

Tests Science

InstallationJuly

High quality alert: ~ 2013

Summary• High-cadence observations using wide FOV are

essential in new generation microlensing planet search

• MOA Group is planning to upgrade existing 1.8-m telescope to get ~ 10 deg^2 FOV

• Design of the new optics has been done. • Technical studies of the CCD camera are going t

o start to solve several problems• After several technical studies and cost estimat

e, we will submit the first proposal in this October.

• If it’s approved, observation will be started in the 2012 bulge season

Merci de votre attention