SP-466 The Star Splitters
 

7

NEW PERSPECTIVES IN ASTRONOMY

 

[79] The data from the HEAOs have opened wide a new window on the universe, allowing us to see the universe from a new perspective, the high energy perspective. As discussed in the chapters to come, because of these three observatories we have increased our understanding of such diverse phenomena as flare stars, newly formed stars, exploding stars, collapsed stars, black holes, the center of our galaxy, other galaxies, clusters of galaxies, and quasars. We have been able to apply this knowledge to questions ranging from the origin of the elements to the size of the universe.

The HEAOs, especially the Einstein Observatory, have changed astronomy in another way. As Herb Gursky pointed out, "Astronomers traditionally have looked to ground-based optical information as the key to astronomical understanding. With Einstein that has changed." The reasons for this change are (1) virtually every known astronomical object, from stars to quasars, has been found to emit measurable X-rays; (2) the quality of data, in terms of spatial and spectral resolution, is comparable to that obtained in the optical region; (3) many phenomena are seen that are invisible with optical telescopes; and (4) large numbers of astronomers have access to the Einstein data as part of a guest observer program.

From the beginning, one of the goals of Riccardo Giacconi and the other members of the Einstein Observatory consortium was to bring X-ray astronomy into the mainstream of astronomy. To do this they not only had to build an observatory that would collect data with a quality of that comparable to the large optical telescopes, they also needed a broad segment of the astronomical community to have access to and contact with the data. To this end, the HEAO scientists and NASA agreed to institute a guest observer program. According to this program, which was administered by Fred Seward of Smithsonian, 20 percent of the observing time for the first year was reserved for guest observers, with an increased percentage reserved for guests after the first year. Over 400 guest observers from over 50 different institutions were accommodated in this way. Thus, in Gursky's words, "Einstein became a universal facility both from the point of view of the range of astronomical phenomena that it can investigate and the vast number of individuals that have access to it. Thus not only the fact but the perception has changed," namely, that astronomy is best done by looking at the universe over a wide range of wavelengths.

The launch dates, the dates on which they ceased operation, and the dates of reentry into the atmosphere are listed in the following table for the....


[
80]

The Gamma Ray Observatory, now under construction and scheduled for launch near the end of the 1980s, will carry gamma ray telescopes that will surpass those of previous gamma ray detectors by an order of magnitude or better.

The Gamma Ray Observatory, now under construction and scheduled for launch near the end of the 1980s, will carry gamma ray telescopes that will surpass those of previous gamma ray detectors by an order of magnitude or better.

 

....three HEAO spacecraft. Although the spacecraft no longer exist, the analysis of the data from the HEAO missions will continue for years, and important new results will be discovered as astrophysicists mine the rich lore of the HEAO data banks. Rather than attempt a complete survey of the scientific results from the HEAOs, I will give a sampling of the results that should impart the flavor and scope of the new discoveries and their impact on our understanding of the universe. Hundreds of scientists from many different institutions have contributed to the work described below; because of their large number, I have regrettably found it impractical to mention them individually by name or to cite their papers. For these important details I refer the reader to the books and journals listed under Additional Reading at the end of the book.

 


[
81]

The Advanced X-Ray Astrophysics Facility has been designated as the highest priority new project in U.S. astronomy for the 1980s by the Astronomy Survey of the National Academy of Sciences.

The Advanced X-Ray Astrophysics Facility has been designated as the highest priority new project in U.S. astronomy for the 1980s by the Astronomy Survey of the National Academy of Sciences. The facility would be launched by the Space Shuttle and be resupplied in orbit. It should have a lifetime of 10 to 15 years. With a 1.2 meter diameter mirror and improvements in the focal plane instrumentation, it should be a hundred times more sensitive than the Einstein Observatory. (Courtesy Harvey Tananbaum)

 

Launch, Termination, and Reentry Dates for HEAO Missions

Mission

Launch

Ceased operation

Reentry

.

HEAO A

12 Aug. 1977

9 Jan. 1979

14 May 1979

HEAO B

13 Nov. 1978

26 Apr. 1981

25 Mar. 1982

HEAO C

20 Sep. 1979

30 May 1981

7 Dec. 1981


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