Solar Images (All ftp)

Solar Images -- Boulder H-alpha film strips are scanned at 4000 pixels per inch 16-bit gray scale on a Nikon Super Coolscan 500 ED scanner (see PDF description) with a density range of 4.8. The scanner has a 3,964-pixel, two-line linear CCD image sensor. The Boulder H-alpha film strips have 12 images per day, with two overexposed images showing the solar prominences on the limb of the solar disk, and occasionally an underexposed black background image that can be used to subtract out any artifacts in the system. Daily images can be 10 seconds apart and are useful for identifying scratches, lint, speckling, and emulsion deposits or other non-solar phenomena on each individual frame.

On the daily images, North is at the top and East is on the left. No corrections are made for the solar P (position angle of axis), Bo (heliographic latitude), and Lo (heliographic longitude) angles. The file names indicate the approximate time of observation (YYYYMMDD_HHMMHFxBO, where HFx=Hydrogen, Film, sequence letter, and BO indicates the station Boulder). The user should read the actual time of observation from the clock located at the top of the image. Some offband images are available, as well as some blowup images of interesting regions of solar activity.

Some History: from SOLAR NETWORKS, a poster produced by Barbara Poppe -- The Boulder Solar Observatory is located on the NOAA campus at 325 Broadway, Boulder, Colorado. Funding shortages have not allowed a continuous solar observing program, but the site is available for special projects.


HISTORY OF THE RAZDOW TELESCOPE

In 1965, NASA was worried about sending astronauts into space, knowing that in space there were dangerous particles which come from the Sun. So they established the Solar Particle Alert Network (SPAN) to provide warnings of hazardous solar particle events. SPAN consisted of a network of solar observatories around the world so observations could be made continuously. The telescopes were designed and built by the Razdow Manufacturing Company in Newark, New Jersey.

By 1967 Boulder became one of the SPAN observatories when it received its Razdow. The telescope would be used to observe solar flares and related solar phenomena. Using a Hydrogen-alpha filter that blocks most of the light, an observer could look through an eyepiece at the Sun, and a 35-mm camera could take constant film footage of the Sun. A TV camera was also mounted to the telescope and projected the image of the Sun on a monitor located in the Space Environment Center operations room.

The Razdow telescope was a valuable part of Space Environment Center history of service for over 30 years. On September 14, 1999, the telescope was moved to this new observatory. The telescope will remain in operation here, providing the Space Environment Center Space Weather Operations with real-time imagery of the Sun.

PHOTOGRAPHING THE SUN The Razdow was equipped with a 35-mm camera for filming the full disk of the Sun. While patrolling, pictures were taken each second. Changes in the features seen here can alert observers that the Sun is about to erupt and send particles and energy our way.

SUNSPOT DRAWINGS One of the products produced at the Boulder Observatory was a daily sunspot drawing -- 1966-1991. These drawings were done by hand as Galileo did them over 400 years ago.

• Archive by year and month, 1967-1994 images;
• Documentation about the image database (WORD doc);