On June 3rd, 2000, Suprime-Cam
obtained its best image to date, with stars appearing a
remarkable 0.3 arcsec in diameter (1/6000 the diameter of
the full Moon) all across the half-degree field-of-view.
This is close to the theoretical maximum sharpness that
can be delivered by the camera (now mounted at Subaru Telescope's
prime focus) and indicates that the repairs done a month
ago to the detached fixed point were done properly. The
excellent performance of Subaru Telescope is unchanged from
prior to the mishap.
Commenting on the exceptional image, Dr.
Satoshi Miyazaki (NAOJ), head of the Suprime-Cam instrument
team reported: "The 0.3 arcsec stellar images really
surprised me... I'm still shaking!" Even from Mauna
Kea, possibly the very best site on Earth for observing
the heavens, it's not often that the atmosphere overhead
is calm enough to show stars as sharply as Subaru Telescope
and Suprime-Cam can image them.
Note that the best images obtainable in
visible light from the surface of the Earth are somewhat
less sharp compared to the best images obtainable using
infrared light. This is why the 0.3 arcsec (visible light)
Suprime-Cam image reported here is as remarkable as the
0.2 arcsec (infrared) image previously reported.
A few days later, Dr. Miyazaki used Suprime-Cam
to obtain images of the spiral galaxy M63 (NGC5055, the
"Sunflower Galaxy"). This galaxy is relatively
nearby at a distance of approximately 24 million light-years
from Earth and is well-known as a place where many new stars
are forming. The Earth's atmosphere on this particular night
wasn't quite as stable as previously, but the images obtained
were still remarkably good, providing us with arguably the
best ground-based image ever obtained for this object. The
color image clearly shows the galaxy's tightly wrapped spiral
arms and a multitude of small reddish HII regions where
hydrogen gas is glowing due to the presence of newly formed
hot massive stars.
June 22, 2000 |
