Image Intensifiers in Astronomy

www.multimediatech.cz © Multimedia Technology Group

České vysoké učení technické v PrazeFakulta elektrotechnickáKatedra radioelektroniky

Technická 2166 27 Praha 6

29/4/2011

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MAIAMeteor Automatic Imager and Analyzer

Image Intensifiers

in

AstronomyStanislav Vítek, Karel Fliegel, Petr Páta, Pavel Koten

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Outline of the talk

Motivation of our work

Description of MAIA system

Image intensifier: good for any science?

Movie

Experiences, conclusions

2/11

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Motivation of our work

Observations of faint meteor showers

Requirements for equipment

Fast enough

High gain

Affordable

Requirements for technical properties are critical

Budget → limited

Human resources → better (students)

3/11

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History

4/11

S-VHS camcorder

25 fps

Records on tapes

Jitter

No cover

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Description of camera

Mechanical componets (A) Outer cover

• Videotec HEG47K2A000• Heating with thermostat• Internal dimensions 134x88x450mm

(B) Inner cover• Model Brůna I• Parts milled from solid aluminium• Precise adjust of all components

5/11

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Description of camera

(2) Key electro-optical components (A) Outer lens

• Pentax SMC FA 1.4/50mm (K-Mount bayonet) (B) Image intensifier

• Philips (Photonis) XX1332• Aperture 50/40mm• Gain up to 60000 lm/lm• Resolution 30lp/mm

(C) Inner lens• Pentax H1214-M 1.4/12mm• Extension 250μm• C-Mount

(D) Camera• JAI CM-040GE• GigE Vision interface (8/10bpp), 1/2” progressive mono CCD• Resolution 776 x 582pix (0,45Mpix) ~PAL• Framerate 61,15fps

Black anodized inner cover

6/11

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Overall description

2 stations (Kunžak a Odřejov) ~ 210Mbps (8bpp @ 60fps, custom video format) ~ 1TB / night video sequences ~ 10 min central DB, batch data processing

7/11

Camera Camera

PC Main PC

HDD array

GigE Vision

Internet

GigE Vision

92.5km

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Image intensifier

Philips (Photonis) XX1332 Image intensifier for night vision Microchannel plate

8/11

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Electro-optical properties

Spectral sensitivity ~ 455-845nm

Non-linear! Automatic gain control

400 500 600 700 800 9000

0.2

0.4

0.6

0.8

1

Wavelength [nm]

Re

lativ

e s

en

sitiv

ity,

Sp

ect

ral t

ran

smis

sio

n [

-]

LensB=0.11

B=0.23

B=0.36

B=0.47B=0.59 B=0.71

10-4

10-3

10-2

10-1

10010

-2

10-1

100

Normalized input power [-]

No

rma

lize

d g

ain

[-]

Overall spectral sensitivity AGC

9/11

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Electro-optical properties

Spectral response of camera ~ 400-725nm

Spectrum on the output aperture of image intensifier ~ 487-571nm

Spectral sensitivity of camera Spectrum on the output of II

400 500 600 700 800 900 10000

0.2

0.4

0.6

0.8

1

Wavelength [nm]

Re

lativ

e r

esp

on

se,

Sp

ect

ral t

ran

smis

sio

n [

-]

Lens

Camera w/o lens

Camera with lens

400 500 600 700 800 900 10000

0.2

0.4

0.6

0.8

1

Wavelength [nm]

Re

lativ

e r

esp

on

se,

Re

lativ

e p

ow

er

[-]

Camera with lens

Relative power

10/11

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Electro-optical properties

Overall resolution Limited by used camera (0,24Mpix in circular aperture)

Output aperture of image intensifier

0 200 400 600 800 1000 12000

0.2

0.4

0.6

0.8

1

Spatial frequency [LW/PH]

MT

F [

-]Overall MTF

Input lens andimage intensifier

JAI CM-040GE

Nikon D700

11/11

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Experiences, Conclusions

Unprotected input aperture → Automatic iris should be designed

New system much better characteristics Not working continuously

12/11

www.multimediatech.cz © Multimedia Technology Group

České vysoké učení technické v PrazeFakulta elektrotechnickáKatedra radioelektroniky

Technická 2166 27 Praha 6

29/4/2011

v1.00

IBW

S 2

011

, K

arlo

vy V

ary

MAIAMeteor Automatic Imager and Analyzer

Thank for your attention