Immediately following is the complete report of the meeting of the National Solar Observatory Users' Committee which was held in Tucson on 20-21 April this year. I am very grateful to the members of the committee, especially its chairman, for their efforts in helping me in maintaining liaisons with our user community this way.
Jacques Beckers
The purpose of the Users' Committee of the National Solar Observatory is to advise the Director on issues concerning operations at the two main sites, Sac Peak and Kitt Peak, from the perspective of current and potential outside users of those facilities. The committee met in Tucson on 20-21 April 1998. In attendance were committee members T. Ayres (Chair, Colorado), T. Brown (HAO), T. Duvall (NASA/GSFC, stationed at Stanford), P. Goode (NJIT), D. Jennings (NASA/GSFC), K.D. Leka (NOAA/SEC), and R. Shine (Lockheed-Martin). E. Hildner (NOAA/SEC) was not able to attend. B. Snavely (NSF) and R. Radick (AFRL; filling in for R.Sagalyn) also were present, speaking on behalf of NSF and USAF interests, respectively. H. Jones described NASA activities, primarily support of the daily magnetograms and 1083 nm images from the KPVT. During the meeting, presentations were made concerning the current status of the Observatory and its projects, and plans for the coming fiscal year.
NSO continues to run the highly successful GONG program, and the team has hopes to upgrade the instruments with high-resolution CCD cameras and operate the network through the current sunspot cycle. The Observatory has begun development work for the recently approved SOLIS project: a cluster of long-term solar monitoring and spectral characterization instruments slated for operation through the first quarter of the 21st century. Work also is proceeding to develop an adaptive optics system for the Sac Peak VTT, building on the successful implementation of an "active optics" compensator over the past several years. The latter has been utilized to ferret out weak links in the current optics of the VTT, and has significantly improved the quality of the images by actively compensating for slowly varying telescope aberrations. A 20-actuator compensator is under development, scalable to the 80 element system needed for full image restoration on the 76cm aperture VTT. The successful demonstration of a true adaptive optics system is considered an essential step along the path toward a major new large-aperture (3-m class) ground-based solar facility. NSO/SP also is participating in the upgrade of the Air Force ISOON solar monitoring system, which will be deployed at four sites around the globe.
At Kitt Peak, the staff helps support a number of visitor instruments in addition to the normal complement of the facility. The Swiss ZIMPOL (imaging Stokes polarimeter) is one example. ZIMPOL I is in active use, exploring the so-called "second solar spectrum" (in polarized light), and a second generation instrument is under development. Another example is the GSFC 12 µm imaging spectrometer used for studies of the magnetically-sensitive Mg I high-Rydberg transitions. In addition, the 1-m FTS supports a wide range of atomic physics investigations, partially supported by grants from NSF and NASA atmospheric chemistry groups. The McMath-Pierce nighttime program is entering its second year of self-funded operations. Digital Archive use continues to expand rapidly: the 300-disk capacity CD-ROM Jukebox currently contains primarily FTS and KPVT data sets; additional acquisitions are being evaluated.
A number of upgrades to the McMath-Pierce telescope and Main spectrograph are underway. One effort is modernization of the telescope control system, with emphasis on guiding and image stabilization. The entrance port from the telescope tunnel into the main observing room has been enlarged to allow access to the entire image when observing at one of the limbs. Two schemes have been advanced to track and stabilize the Main image. The simpler of the two would be permanently installed above the Main spectrograph and serve it exclusively; while the other---more general, but more complex---scheme would operate immediately after the heliostat so that it could serve any of the observing stations (e.g., the FTS). However, since only the Main spectrograph has image rotation compensation, the utility of high-stability guiding and tracking at the other ports is debatable.
A second effort involved modernizing the "photometry" system on the Main spectrograph. The grating mechanism now is under full computer control. A major beneficiary of the upgrade will be long-slit infrared imaging. Previously, camera flatfields based on combining spectrally smeared frames had to be done laboriously by hand (literally, "turning the crank"); now, such critical observations can be done in an automated (and more reproducible) fashion.
A third major effort at the McMath-Pierce concerns the cryogenic camera system used in the Near Infrared Magnetograph (NIM 1, a long-slit grating system; and NIM 2, currently under development, utilizing a Fabry-Perot etalon). (Note: the NIM camera system also supports long-slit unpolarized infrared spectral observations with the Main spectrograph.) A controller and dewar are slated for purchase, to run one of the high-sensitivity 1K × 1K "Aladdin" InSb chips, developed at NOAO for nighttime astronomy. The implementation of new infrared spectral capabilities on the McMath-Pierce also is considered important groundwork for a future large-aperture solar facility.
Progress in the latter area---the so-called Advanced Solar Telescope---has mainly been confined to continued seeing tests at various sites using scintillometers, and further refinement of that technique. The ultimate goal of replacing the aging and outdated (although still highly productive) solar facilities at the two current NSO sites hinges on the results of the Parker Committee, whose report was not yet available at the time of the Users' Committee meeting, but is expected later in the summer (1998).
Another key issue was the selection of a new Director for NSO, to replace current Director Jacques Beckers when he steps down this fall. The search committee, chaired by Jack Thomas (Rochester), had not yet begun their deliberations at the time of the Users' Committee meeting.
The committee is encouraged by the vitality of NSO---in the face of its perennial funding difficulties---as evidenced by the high rating and selection of the SOLIS project, the stepped plan and visible progress of the AO work, and the modernization efforts at the McMath-Pierce which promise significantly improved observations at the worlds largest solar telescope. The committee strongly endorses NSO's efforts to develop the 20 Zernike AO system as an important adjunct to the AST work, seek a commitment from NOAO to acquire a 1K × 1K Aladdin device, and pursue funding for the camera upgrade and long-term operation of the GONG network. The Committee again voiced its concerns over the futures of some of the younger staff members, on whose shoulders much of the key AO and AST development work disproportionately falls. We urge the Observatory to make allowances for the negative impact of such "service work" on the productivity of these staff members at this critical stage of their careers, when considering such staff for promotion and/or tenure. The Committee also is concerned over the impact of the several development projects on the ability of the scientific staff---already thinly spread---not only to carry out the projects successfully, but also to support outside users of the facilities at the SP and KP sites. An example of the dilemma is the RISE/PSPT program, for which development and construction funds were provided, yet no operations money was secured for the Sac Peak component of the network. This presents a difficult choice for the Observatory: run the PSPT, and give up one of the other high-priority claims on the base budget; or relinquish NSO involvement in the operations of a key project that it helped initiate. We urge the Observatory to consider carefully the operations implications in any new projects in which it wishes to become involved; and to secure firm commitments for funding said operations before accepting the responsibility for such projects. In the case of RISE/PSPT, the committee firmly believes that it is the clear responsibility of the Atmospheric Sciences Division at NSF to support the operations and maintenance of the Sac Peak component of the network, and we encourage the NSO to pursue that avenue vigorously. The committee noted that one key area of support, namely online documentation for the available facility instruments (and visitor instruments, if applicable), could be improved significantly. Finally, the committee commends current Director Beckers for his successful leadership of the Observatory through the difficult period of the past several years. We sincerely hope that Beckers will continue to champion a state-of-the-art groundbased solar facility, and that his successor will embrace that vision as well.
Tom Ayres, Chair, NSO Users' Committee