Instrument Overview

IR2 utilizes the atmospheric windows at wavelengths of 1.74, 2.26, and 2.32 μm; the first two suffer only CO2 absorption, while the last one contains a CO absorption band. At these wavelengths the outgoing infrared radiation originates from the altitudes 35 -- 50 km.


Definition of Product Level

Level 1b (l1b)
raw data (count value in FITS format)
Level 2b (l2b)
calibrated data (physical value in FITS format)
geometry (geo, geo4)
geometry information (latitude, longitude, local time, phase angle, incidence angle, emission angle, azimuthal angle) at the center of each pixel (geo) and at the lower-left corner of each pixel (geo4).
Level 3 (l3, l3x)
calibrated, physical values at equally spaced longitude-latitude grid in NetCDF format, derived from l2b data (l3), and pointing corrected geometry information at the center of each pixel (l3x).
Cloud Motion Vector (CMV)
CMVs at equally spaced longitude-latitude grid in NetCDF format obtained by using l3 data.

File Naming Convention

Filename is in "CAM_DATE_TIME_KIND_LEVEL_VER.EXT" format.

Name of the camera: ir2 for IR2.
date in UTC when image taken at in "YYYYMMDD" format, where YYYY is four-digit year (2010 -- 20??), MM is two-digit month (01 -- 12), and DD is two-digit day (01 -- 31): e.g., 20151211 for 2015-12-11.
time in UTC when image taken at in "hhmmss" format, where hh is two-digit hour (00 -- 23), mm is two-digit minutes (00 -- 59), and ss is two-digit seconds (00 -- 59): e.g., 123704 for 12:37:04.
kind of filter or image type: 174 for 1.74 μm filter, 226 for 2.26 μm filter, 232 for 2.32 μm filter, 202 for 2.02 μm filter, 165 for 1.65 μm filter, and drk for dark image.
level of product: l1b, l2b, l3, l3x, geo, and geo4.
version string: v10 for "version 1.0".
extension that represents file type: fit for FITS file, jpg for JPEG file, png for PNG file, lbl for PDS3 label file, and nc for NetCDF file.

Data Processing tools


When you publish your own work based on the AKATSUKI IR2 data, please refer to the following paper(s):

  1. Satoh, T. M. Nakamura, M. Ueno, K. Uemizu, M. Suzuki, T. Imamura, Y. Kasaba, S. Yoshida, M. Kimata, Development and in-flight calibration of IR2: 2-μm camera onboard Japan's Venus orbiter, Akatsuki, Earth, Planets and Space, 68:74, doi:10.1186/s40623-016-0451-z, 2016. URL

Related Papers

Please see list of publications of AKATSUKI


For questions concerning this archive:

Shin-ya Murakami, Japan Aerospace Exploration Agency, murashin _AT_
Yukio Yamamoto, Japan Aerospace Exploration Agency, yukio _AT_

For questions concerning the data:

Takehiko Satoh, Japan Aerospace Exploration Agency, satoh _AT_