Q. When was the "Hinode" satellite (SOLAR-B) launched?

A. It was launched at 6:36 am, September 23, 2006 (Japan Standard Time).

Q. Where was "Hinode" launched from?

A. It was launched from Uchinoura Space Center in Kagoshima Prefecture. It was the last scientific satellite that the Institute of Space and Astronautical Science launched with a M-V rocket.

Q. How big is "Hinode"?

A. "Hinode" is ~1.6 m long, 1.6 m wide, and 4 m high. If you set the satellite vertically, its height is more than twice the height of an adult. In addition, the length of the extended solar panel is 10 m.

Q. What is the difference between "Hinode" and "Yohkoh"?

A. "Yohkoh" mainly observed the Sun with X-rays, while "Hinode" observes with visible light and extreme-ultraviolet rays in addition to X-rays.

Q. What are the distinguishing characteristics of "Hinode" as a solar observation satellite?

A. The main characteristics are the high spatial resolution and the long term stability of the magnetic field observations.

Q. How high do you mean when you say "high spatial resolution"?

A. The spatial resolution of the Solar Optical Telescope (SOT) is 0.2 - 0.3 arcseconds (depending on the observation wavelength). It can capture phenomena on the solar surface whose scale is around 140 - 210 km. In terms of eyesight, this corresponds to about 6000/20 vision. This is about 300 times finer detail than the human eye can distinguish. Also, the X-Ray Telescope realizes an unprecedented high spatial resolution of about 1 arcsecond (corresponding to about 700 km on the solar surface).

Q. How long is the expected lifetime of "Hinode"?

A. The design lifetime was 3 years, however it has been operating for 10 and a half years as of March, 2017. We expect to continue collecting valuable solar data for several more years.

Q. Does "Hinode" go around the Sun?

A. No, it goes around the Earth. It is important that it orbits outside of Earth's atmosphere. Ground-based observations are affected by atmospheric fluctuations and can't observe ultraviolet rays and X-rays which are absorbed by the atmosphere.

Q. The distance from "Hinode" to the Sun isn't that much different than the distance if you observed from the Earth, so why can "Hinode" take such beautiful images?

A. It can take beautiful images because it takes pictures from outside of the Earth's atmosphere, so it isn't affected by atmospheric fluctuations. Also, it has a big mirror for a spaceborne telescope enabling high spatial resolution, making it possible to take beautiful images, even from a distance.

Q. How high does "Hinode" fly above the Earth?

A. It flies at an altitude of ~ 680 km.

Q. How long does "Hinode" observe? How many hours are there when "Hinode" cannot observe the Sun because it is in the shadow of the Earth?

A. "Hinode" orbits in a Sun-synchronous polar orbit. This orbit is only a little off from the day/night terminator, and passes over the North Pole and the South Pole. Therefore, most of the time "Hinode" can observe the Sun, but there are times that it cannot observe the Sun because it goes into the Earth's shadow for a few hours a day for 2 months of the year because the Earth's daily rotation axis is tilted.

Q. Who made"Hinode"?

A. The National Astronomical Observatory of Japan (NAOJ) and Japan Aerospace Exploration Agency (JAXA) collaborated to make"Hinode."The mission instruments for solar observation were made by collaborations among the U.S.A., U.K., and Japan.

Q. When did the "Hinode" project begin?

A. Voluntary studies started just after Yohkoh's launch (~ 1993). The "Hinode"project officially started in 1998, however it took more than 8 years until the launch in 2006.

Q. How many people are involved in "Hinode"?

A. All told, nearly 300 people are involved in operating "Hinode" at NAOJ, JAXA, various companies, and around the world.

Q. What does "Hinode" look at on the Sun?

A. It observes visible light, extreme ultraviolet rays, and X-rays emitted by the Sun. The solar atmospheric layers such as the photosphere, chromosphere, and corona emit different wavelengths of light, so you can see each atmospheric layer by changing the wavelength of light you observe. Through spectro-polarimetric observations of the spectral lines emerging from the photosphere, the magnetic field can be measured. Also by performing spectroscopy on the extreme ultraviolet emission lines from the transition region and corona, we can measure the plasma velocity along the depth (line of sight) direction. With these observations, we are trying to solve the mysteries of solar physics, such as the reasons why the corona is very hot and how solar flares occur.

Q. Can "Hinode" see inside the Sun?

A. No. "Hinode" cannot see inside the Sun directly. However, the research to probe the solar interior using helioseismic methods is ongoing.

Q. Does "Hinode" observe objects other than the Sun?

A. No. It doesn't usually observe other objects. However, other things like the Moon, Mercury, Venus, or comets have come into the field of view of Hinode's telescopes and been observed as they go near the Sun or pass in front of it.

Q. Can you see the solar images observed by "Hinode" in real time?

A. "Hinode" sends observed data when it passes over the ground based receivers, this is called a 'downlink'. You can never watch in real time because there is always the downlink time lag.

Q. Do you recommend any books to learn more about the Sun?

A. We recommend the following book:
Edward G. Gibson: The Quiet Sun, University of California Libraries (January 1, 1973)

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