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 36 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.
* Low Resolution (JPEG 115KB)
* High Resolution (JPEG 663KB)
Image Caption (TEXT)
Title: 0.3 arcsec Stellar Image Size with Suprime-Cam
Object Name: Spiral Galaxy (M63, NGC 5055)
Telescope: Subaru Telescope / Prime Focus
Instrument: Suprime-Cam
Filter: B (0.45micron), V (0.55micron), H alpha (0.65micron)
Color: Blue (B), Green (V), Red (H alpha)
Date: UT2000 June 10
Exposure: 45 sec (B), 15 sec (V), 30 sec (H alpha)
Field of View: 5.0 x 6.6 arcmins
Orientation: North up, East left
Position: RA(J2000.0)=13h15m49.1s
          Dec(J2000.0)=+42d01m43s (Canes Venatici)
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