This image of the Sun's corona was made from a composite of eight separate photographs made by Fred Espenak from Dundlod, India during the total solar eclipse of 1995 October 24. The photos were made on Kodak Royal Gold 100 with a Nikon FE w/MD-12 motor drive, a Sigma 400mm f/5.6 APO telephoto and a Sigma 2X teleconverter. Exposures were 2, 1, 1/2, 1/4, 1/8, and 1/15 and 1/125 seconds. After development, the images were transferred to Kodak photo-CD. Wendy Carlos then used Abobe PhotoShop and a Macintosh IIfx to combine the eight images into one composite image.
The techniques used were orignally developed over a period of a dozen years, using traditional photo darkroom tools then available. Each images was masked to allow only that portain which contained real image data to contribute to the final composite. So the usual burned-out or underexposed coronal portions were removed. The good parts were graded to fit the dynamic range of final print materials, darkening the bright inner portions, while lightening the outer dim parts.
These same hand-tuned processes were adapted to computer image software, with added features, like checking that the allignment between original frames is exact, enhancing low-contrast differences, and removing glitches and grain noise. It still requires many hours and a deft experienced hand to pull it off. Observing many total eclipses gives you the memory of what the desired goal ought be: a natural portrait of what your eye and brain see during totality!
Photo ©1996 Wendy Carlos and Fred Espenak
The photos were made with a Nikon FE and a Sigma 400mm APO f/5.6 lens using a 2x Tamron converter to give 800 mm at f/11. Exposures were 1/125 s for the diamond ring shots and 1 s for the shot of totality. The photographs were made on Kodak Royal Gold 100 which was developed and digitized onto a Kodak Photo CD.
Note: The JPEG images to which the above links point contain subtle shades color and are best viewed with a 16-bit or deeper display.
Because of Yohkoh's motion relative to the path of totality, the apparent motion of the moon relative to the Sun is fairly complex. A plot of the paths in each of three orbits is available as in .pdf format.
In order to produce these movies in as timely a fashion as possible, raw images from the Yohkoh Soft X-ray Telescope (SXT) were used: background has not been subtracted, nor have "hot spots" on the CCD detector been eliminated. You see the data as they first appeared on the ground.
The SXT images used for these movies show plasma in the Sun's tenuous, outer atmosphere, the corona, at temperatures at or above 1,000,000 K.
The Yohkoh ("Sunbeam") Soft X-ray Telescope (SXT) was prepared by the Lockheed Palo Alto Research Laboratory, the National Astronomical Observatory of Japan, and the University of Tokyo with the support of NASA and ISAS (Japan's Institute of Space and Astronautical Sciences).
Note: Thanks to Jim Lemen of the Lockheed Palo Alto Research Labs, we now (1995 October 24, 22:37 UT) have much cleaner, processed images from which we have made new version of the movies below. If you downloaded the raw movies at an earlier time, you might want to take a look at the newer versions.
The following movies are now available:
Still pictures will be posted as we receive them, though it will be some days before we begin to get many ground-based images.
Also of interest: the Yohkoh eclipse planning page, with maps of the moon's location relative to the Sun from the orbit of Yohkoh.
The photograph of the solar corona was taken with a camera system developed by Gordon A. Newkirk, Jr. This specialized instrument photographs the corona in red light, 6500 A -- through a radially graded filter that suppresses the bright inner corona in order to show the much fainter streamers of the outer corona in the same photograph.
As the photograph was taken early in the eclipse, prominences on the east limb are visible. Other features of note are the polar plumes, and the non-radial nature of the southwestern streamer. An additional highlight of the SW streamer was a coronal mass ejection observed in its vicinity by the Mauna Loa Solar Observatory approximately 10 hours after the eclipse.
The High Altitude Observatory White Light Coronal camera image is available in both
formats, courtesy of the HAO eclipse team:
Click here for a larger version (JPEG, 77 Kbyte)
The image currently served in these formats has been digitally enhanced to remove stray light due to cirrus clouds.
Click here for technical information on the HAO eclipse image.
If you have the bandwidth, the patience, and a QuickTime player, we recommend the QuickTime version, not only because the resolution is better than in the MPEG movie, but also because the sound of the whooping eclipse afficionados is half the fun.