System Details and Calibrations of the CRL-ASI

Minoru KubotaCommunications Research Laboratory Contents

• System details of the CRL-ASI

• Calibration and data processing for the CRL-ASI

Instruments and Targets of the Alaska project

2000 ～

System details of the CRL-ASI

System diagram of CRL-ASI

Size and externals

Fisheye Nikkor

• f6 mm

• F1.4

• FOV 180o

• Weight: 5 kg

Optical system

Total transmission of fisheye lens and telecentric lens system

80 mm Bright and Precise!

PixelVision

SpectraVideo Camera Model SV512

• format: 512×512

• Back-illuminated CCD (SITe)

• O-ring Dewar

• 3-stage thermoelectric cooler (minimum temp. ~225K)

• dark current: ~0.5 electron/pixel/sec@230K

• readout noise: ~12 electron,rms@100kHz-readout

Detector (CCD camera)

Quantum efficiency of the back-illuminated CCD

Functions:

decision of observation period and sequence

filter-channel control

focus control

CCD camera control (temperature setting, exposure, data readout ..)

data saving

making QL-images and display

operation from a remote-site

Programming Language:

Visual C++, Visual Basic, and IDL

OS: Windows NT

Control software

Control panel of the CRL-ASI

SALMON is developed using a high-speed computer networks, for effective use and

display of the data observed in Alaska and for assistance in the data distribution. The

system has capabilities of quasi-real time data transfer to CRL from Alaska, real time

data displays on the world wide web.

SALMON

(System for Alaska Middle Atmosphere Observation Data Network)

Please add SALMON in your bookmark!!

http://salmon.crl.go.jp/

Calibration and Image Data Processing of the CRL-ASI

Sensitivity calibration using an integrating sphere

Aug. 1999 in NIPR, Japan

Image of the integrating sphere

It shows that luminosity (sensitivity) drops towards the edge of the image.

(mainly by vignetting)

Image data processing

WWWreal-time displayftp

[F. Kasten, Arch. Mateorol. Geophys. Bioklimatol., p206, 1966]

100 km alt.

Variation of the van Rhijn correction factor combined with atmospheric extinction versus zenith angle.

Geometry of the van Rhijn effect and atmospheric extinction

CRL-ASI Observations at Poker Flat

: ASI field-of-view for an assumption of observation altitude of 100 km.

: ASI field-of-view for 250 km altitude.

Observatory: Poker Flat Research Range (PFRR) LAT. 65.1oN、 LON.147.5oW MLAT65.5o

Observation Periods: Oct., 2000 ~ Apr., 2001 Sept., 2001 ~ Mar., 2002 Sept., 2002 ~ Mar., 2003 Sept., 2003 ~ Mar., 2004 2004 ~ ?

Target emissions, filter details, and exposure times for the CRL-ASI in 2000