1. Meteorological Satellites

This Web site uses observation images by the following satellites.

衛星ID	愛称	衛星名
GMS1	Himawari 1	Geostationary Meteorological Satellite 1
GMS2	Himawari 2	Geostationary Meteorological Satellite 2
GMS3	Himawari 3	Geostationary Meteorological Satellite 3
GMS4	Himawari 4	Geostationary Meteorological Satellite 4
GMS5	Himawari 5	Geostationary Meteorological Satellite 5
GOE9	(Pacific) GOES 9	Geostationary Operational Environmental Satellite 9
MTS1	Himawari 6	MTSAT-1R
MTS2	Himawari 7	MTSAT-2

The period of usage is summarized in the following. Notice that the lack of period o GMS1 between 1979 and 1981 is due to the unavailability of data, and GMS1 (Himawari 1) satellite had been operational for this period.

ID	Start	End
GMS1	1978-12-01 0:00 (UTC)	1979-12-01 9:00 (UTC)
GMS1	1981-03-01 0:00 (UTC)	1981-12-21 0:00 (UTC)
GMS2	1981-12-21 3:00 (UTC)	1984-01-21 0:00 (UTC)
GMS1	1984-01-21 9:00 (UTC)	1984-06-29 12:00 (UTC)
GMS2	1984-06-29 18:00 (UTC)	1984-09-27 0:00 (UTC)
GMS3	1984-09-27 6:00 (UTC)	1989-12-04 0:00 (UTC)
GMS4	1989-12-04 6:00 (UTC)	1995-06-13 0:00 (UTC)
GMS5	1995-06-13 6:00 (UTC)	2003-05-22 0:00 (UTC)
GOE9	2003-05-22 6:00 (UTC)	2005-06-28 3:00 (UTC)
MTS1	2005-06-28 4:00 (UTC)	2007-06-04 4:00 (UTC)
MTS2	2007-06-04 5:00 (UTC)	2007-06-06 4:00 (UTC)
MTS1	2007-06-06 5:00 (UTC)	2009-02-17 3:00 (UTC)
MTS2	2009-02-17 4:00 (UTC)	2009-02-18 10:00 (UTC)
MTS1	2009-02-18 11:00 (UTC)	2009-11-11 14:00 (UTC)
MTS2	2009-11-11 15:00 (UTC)	2009-11-12 3:00 (UTC)
MTS1	2009-11-12 4:00 (UTC)	2009-11-15 23:00 (UTC)
MTS2	2009-11-16 2:00 (UTC)	2009-11-27 3:00 (UTC)
MTS1	2009-11-27 4:00 (UTC)	2010-07-01 2:00 (UTC)
MTS2	2010-07-01 3:00 (UTC)	2010-10-07 2:00 (UTC)
MTS1	2010-10-07 6:00 (UTC)	2010-12-22 2:00 (UTC)
MTS2	2010-12-22 3:00 (UTC)	2011-08-03 0:00 (UTC)
MTS1	2011-08-03 3:00 (UTC)	2011-08-16 1:00 (UTC)
MTS2	2011-08-16 2:00 (UTC)	2011-11-01 2:00 (UTC)
MTS1	2011-11-01 3:00 (UTC)	2011-12-26 4:00 (UTC)
MTS2	2011-12-26 5:00 (UTC)	2012-10-18 2:00 (UTC)
MTS1	2012-10-18 3:00 (UTC)	2012-12-26 2:00 (UTC)
MTS2	2012-12-26 3:00 (UTC)	Present

The history of those satellites are summarized in Japan Meteorological Agency | History of Japanese Meteorological Satellites (in Japanese).

2. Meteorological Satellite Images (Photographs)

This web site uses the word "meteorological satellite images" instead of "meteorological satellite photographs" because the way the satellite takes pictures of the earth is different from the ordinary cameras with respect to the following points.

The satellite image is not taken in the same way as a photograph that is shot by closing the shutter of the camera and takes the whole picture at once. A geostationary meteorological satellite, such as "Himawari," needs more than 20 minutes to scan from the Arctic down to the Antarctic, so clouds in the Arctic and the Antarctic have 20 minutes difference in the time of shot. The time of shot at Tokyo, for example, is either 30m25s or 18m25s of every hour for GOES-9, according to the fixed point observation at Tokyo.
The satellite image takes information other than light visible to the human eye. Infrared light, for example, makes us possible to take pictures even in the night, compared to visible light which is only effective with the presence of the sun.

Those are the reasons we prefer the word "image" than "photograph." More detailed information is available in the following pages.

In terms of visible images, on the other hand, sensors work effectively only during daytime. Hence we set up the schedule of generating visible images as follows. Here JST is explained in The expression of time.