Appendix 2 — Committees of the AAVSO

For more information on any program, please contact the committee Chair (listed on a separate sheet in the new member package), visit the "Observing Programs" section of the AAVSO website or contact AAVSO Headquarters. In general, all questions, correspondence, requests for charts, and submission of data for any of these committees should be sent directly to the committee Chair.

A brief description of each program follows:

Charge-Coupled Device (CCD)
The developing technology of Charge-Coupled Devices (CCDs) plays an important role in the AAVSO's mission of monitoring variable stars. A CCD camera contains a light-sensitive silicon chip that produces an electrical signal, which in turn is processed and displayed on a computer monitor. When mounted on your telescope, the result is a digital image of the star field you are observing.

CCD image of FO Per by R. Zissell.

Since they are about 30 times as sensitive as the best photographic emulsions, CCDs make it possible to obtain fainter observations of variable stars, thus complementing the AAVSO visual and photoelectric programs in a significant way. The data obtained can easily be stored for future analysis.

Gary Walker's telescope with CCD.

Standard equipment for CCD observing is a moderate- or large-aperture telescope, a CCD camera, appropriate red-blocked BVRI filters, and CCD reduction software.

The AAVSO has prepared special charts for CCD observing of several stars in its visual observing program which are very faint at minimum. These charts may be obtained free-of-charge from Headquarters or downloaded from the AAVSO website.

CCD observers also participate in the AAVSO International High Energy Network and Exoplanet Transit Search Programs. For more details on these programs and other information relative to CCD observing, please visit the CCD Observing Program section of the AAVSO website.

Photoelectric Photometry (PEP)
If you have a good 6 or 8 inch telescope with a reliable clock drive, and a photoelectric photometer with appropriate filters, you are encouraged to participate in the AAVSO PEP Observing Program. A photoelectric photometer is an electronic device you can make or buy that converts a low-intensity light signal into an electronic pulse. The pulse is then amplified and displayed as a number from which the magnitude of the object you are observing can be determined very precisely.

Kevin Krisciunas' 6" reflector with Photoelectric Photometer

To ensure standardized observing of stars in its PEP Observing Program, the AAVSO has developed special PEP finder charts which are available from the chart section of the AAVSO website or from the Chair of the committee. An AAVSO PEP Chart Catalog is also available from the website or from AAVSO Headquarters. Please visit the PEP Observing section of the AAVSO website for more information.

Eclipsing Binary (EB) and RR Lyrae
Visual observation of eclipsing binary and RR Lyrae stars is a valuable contribution that interested observers can make (see Chapter 3 for a description of these types of stars). These stars need far more observations on a continuing basis than can be made by professional astronomers. One reason for the importance of making these observations is that many of these stars, especially eclipsing binaries, undergo period changes which need to be tracked.

Special techniques are required for observing EB and RR Lyrae stars, and advance planning is essential to acquiring useful data. For example, with eclipsing binaries, it is only necessary to observe them just before, during, and after an eclipse takes place. Also, since the eclipses often occur in just a matter of hours, the time of each observation must be recorded much more accurately than with regular variable star observations. Charts and more information on observing techniques can be obtained from the committee Chair or found on the AAVSO website.

Solar
The main activity of the AAVSO Solar Observing Program is the monitoring of sunspots, from which the American Relative Sunspot Numbers (Ra) are computed. This program, started in 1944, produces an independent sunspot index.

Photo of sunspot group by Art Whipple

The AAVSO Solar Observing Program also includes the work of a smaller group of observers who monitor very low frequency radio stations for sudden enhancements of their signals (Sudden Ionospheric Disturbances or SIDs), and thus detect solar flares indirectly.

Each month, both the computed values of the American Relative Sunspot Numbers and of the SIDs, are forwarded to the National Geophysical Data Center (NGDC) of the National Oceanic and Atmospheric Administration (NOAA).

For more information, please visit the Solar Program section of the AAVSO website.

Elizabeth Eggleston and Celestron with solar filter

Nova Search
The Nova Search Program of the AAVSO was established in the early 1930's with the belief that a serious stargazer can render valuable contributions to astronomy with a systemized visual search for and discovery of novae in the Milky Way. Those regions in our galaxy where novae are most likely to occur have been divided into areas. An observer who is interested in searching for novae is assigned specific areas, but once you have searched these, you can go on to other areas, thus encouraging a thorough coverage of the sky. In addition to searching specific areas, an observer can also add a "dome search" to his program. This is a naked eye scan of the whole visible sky, whose purpose is to catch a bright nova among the brightest stars (down to 3rd magnitude) of the constellations.

The standard equipment for the AAVSO Nova Search is a good atlas, such as the AAVSO Variable Star Atlas, and a pair of 7 x 50 binoculars.

At the end of each month, the observer uses special forms to report the dome and area searches and faintest magnitudes checked. Potential discoveries are verified by an experienced observer. If an object is verified as "new," the AAVSO Director is contacted immediately. Upon having the discovery confirmed, he/she contacts the Central Bureau for Astronomical Telegrams at the Smithsonian Astrophysical Observatory, to alert the astronomical community via the International Astronomical Union Circular.

Supernova Search

AAVSO Supernova Search committee chair, Robert Evans, presents Nova Award to Samantha Beaman, April 1996.

Standard equipment for this search is a telescope capable of making useful observations of galaxies (usually "seeing" 14th magnitude stars, at least), and a collection of reference charts and photos showing the normal appearance of all the galaxies which the observer is currently monitoring. Negative galaxy observations and observations of supernovae should be reported to AAVSO Headquarters.