Mario Motta
“Microvariability of CH Cygni at Minimum”
CH Cygni is a symbiotic star system that has been shown to have multiple variable periods ranging from minutes to over 1000 days. During the annual 1999 meeting I presented data documenting the microvariability of CH Cygni. That data spanned a time that had CH Cygni at a visual magnitude of 7.4. This past summer CH Cygni dimmed to visual, and this paper will document its behavior (microvariability) at its minimum state.

John Pazmino
“The Promise for Starry Eyes”
A progress report on New York’s eradication of luminous graffiti at the end of the 20th century and the promise for starry eyes for the 21st century.

Regina Jorgenson & Vladimir Strelnitski
“Complex Variability of the Peculiar Emission-Line Star MWC349”
We'll review the results of a multi-wavelength study of the unique variable star MWC349 at the Maria Mitchell Observatory. This early-type, emission-line star is the only known natural hydrogen maser and the only known natural laser, both originating in the ionized, expanding atmosphere of an edge-on circumstellar disk. We have studied the variability of the star on the red photographic plates of the Harvard plate collection (for the years 1967-81) and monitored it for three years (1997-2000) in UBVRI (with the 31-inch CCD telescope of the Lowell Observatory in Flagstaff) and in the millimeter radio domain (with the 12-m NRAO radio telescope on Kitt Peak). We reveal several types of variability in this star: long time-scale variations with a probable quasi-period of 9.2 years and a relatively large amplitude (+/- 0.4 mag) in the red photographic domain; small-amplitude (+/- 0.07 mag) variations with a quasi-period of 1.5 years in all the observed colors of the optical domain; complex variations, with several different time scales, in the masing hydrogen recombination radio lines, and probably, slight variations of the radio continuum that correlate with those of the optical light. We will discuss possible physical mechanisms responsible for all these variations.

Ronald E. Royer
“Slow Death of SN1999em”
SN1999em in NGC1637 faded slowly. This observer wonders about the scientific value of AAVSO CCDers following supernovae into the inner-inner sanctum.

Frederick R. West
“Favorable Times Predicted for Searching for Transits of Gliese 876 by its Extrasolar Giant Planet”
The most favorable times for detecting possible transits of Gliese 876 by its extrasolar giant planet have been calculated using the spectroscopic binary orbital elements found by Marcy et al., (1998) for this star. The first transit opportunity will occur about December 11, 2000. Possible depths of transits are computed assuming radii of 70,000 km for the planet and 170,000 km for Gliese 876. Limits are found for the inclination of the planet’s orbit to the plane of the sky and on the mass of the planet for the case where no transit occurs.

David B. Williams, Marvin E. Baldwin, Peter Guilbaut, Arne A. Henden, Daniel H. Kaiser, Gilbert C. Lubcke, & Gerard Samolyk
“The New Algol-type Eclipsing Binary GSC 3002-454“
Photographic, visual, and CCD photometry indicates that the star GSC 3002-454 in Ursa Major is an Algol-type eclipsing binary, range 12.8-15.0 V, period 1.8559121 days. Secondary minimum is 0.10 V. Eclipses are total with constant light lasting 0.04 day.

Shay Holmes & N.N. Samus
“UBVRI Photometry of DE CVn”
DE CVn (RX J1326.9+4532) is a poorly studied, unusual eclipsing binary. Robb et al. (1997) have detected in R probable instability of the light curve from period to period and a deep narrow dip near the center of the primary minimum. Their conclusion that the secondary component of the system is a white dwarf and that the system is very close to us (60 pc) makes it an interesting target for a thorough photometrical study. We will present the first results of our CCD UBVRI photometry of the star with the 31-inch telescope of the Lowell Observatory during five nights in June 2000. Our most important new result is a drastic increase of the depth of the primary minimum with the decreasing wavelength - from approximately 0.1 mag. in I to approximately 1 mag in U. At least one of our observations fell on the center of the primary minimum and confirmed its narrowness and depth at long wavelengths. Our observations demonstrate obvious changes of the form of the light curve from cycle to cycle.

Kevin B. Marvel, Phil Diamond, & Athol Kemball
“The SiO Masers of TX Camelopardalis”
Observations of evolved stars with the very Long Baseline Array have shown that silicon monoxide masers are found just above the photospheres of these interesting objects. By observing many times over a few pulsation periods, researchers are now discovering complex motions in the extended photospheres of these bloated, old stars. We will present several dramatic ‘movies’ of these sources and speculate on what such observations can tell us about the physical conditions near the star.

Casper H. Hossfield
“The Wolf Number Mystery”
During World War II The Interservice Radio Propagation Laboratory, IRPL, asked the Department of Terrestrial Magnetism, DTM, of the Carnegie Institute of Washington, CIW, to set up a small group of sunspot observers to duplicate the Zurich Sunspot Relative Number preliminary index, RZ, that IRPL was then using to calibrate nomograms they used to predict the best frequencies for shortwave radio communication. In 1882 Zurich had changed their system of counting to counting all of the spots and small pore groups. They then multiplied these larger sunspot counts by a scale factor, 0.60, each day to reduce the new RZ index to the original Wolf scale, which was 1.00 by definition. This then, was the RZ index IRPL was using to calibrate their nomograms. The DTM mistook Zurich's scale factor, 0.60, for an observatory constant thinking it reduced Zurich's sunspot counts to Wolf Numbers. Because DTM wrongly assumed RZ was still a Wolf Number index they then computed observatory constants against RZ for their three DTM observers, The US Naval Observatory, Mount Holyoke Observatory and Neal Heinz, an expert sunspot observer. These three observers then counted only the larger sunspot groups the way Wolf would have counted. This Wolf number index, based on the wrong system of counting, was later turned over to the National Bureau of Standards, NBS. The fact that it was a Wolf number index, and not based on the new Zurich system of counting that produced the preliminary RZ index that IRPL was then using, and had been using for over ten years, and the index IRPL actually wanted duplicated, was never noticed by NBS. Later, responsibility for producing this index, still based on the wrong system of counting only the larger sunspot groups, was transferred to the National Oceanographic and Atmospheric Administration, NOAA. It was not noticed by NOAA either, that it was based on the wrong system of counting. Today 56-years later NOAA still publishes sunspot numbers that they call Wolf Numbers, which of course they are. But they are still based on the wrong system of counting. They are not the preliminary RZ index that was based on a count of all of the spots that IRPL was using to make their forecasts and wanted duplicated in 1945. I trace the long history of this unbelievable mistake using published documents by the principals involved. These documents can all be found in the library and archives of the American Association of Variable Star Observers, AAVSO.

Philip A. Dombrowski
“Secrets in Starlight: The Strange Case of R Coronae Borealis”
This high school science project attempts to provide an explanation for the varying light output of 1544+28A R Coronae Borealis. Using my own visual data in conjunction with published spectroscopic data, the star's reason for variability was explored.

Visual analysis of the behavior of R CrB was achieved from 85 observations collected over a period of 331 nights using instruments ranging in size from 7x50 binoculars to a 12" Schmidt-Cassegrain telescope.

Through research and data collection, I have determined that R CrB is an old star that has finished fusing hydrogen into helium, and now fuses helium into carbon. The fusing of helium into carbon forms dust (carbon) clouds. The variable density of the cloud yields changes in the brightness of R CrB.

The value of investigating the nature of R CrB was an attempt to develop a sound explanation of what is happening astrophysically by incorporating all of the measurable properties and changes in starlight. By applying our understanding of astrophysics, the understanding of stellar evolution is further developed. From this study alone, it has been determined that R CrB is an ancient star undergoing rapid adjustment to maintain stability in its fusion process.

Courtney Peterson, N.N. Samus, Shay Holmes, & Karyn Singer
“Lost Variables in Sagittarius and Cygnus Recovered on Nantucket Plates”
Mass discoveries of variable stars in modern automatic surveys make it very important to find out accurate positions for all variable stars known previously. Some of the "old" variable stars have only rough coordinates and no finding charts ever published. The existing collections of sky photographs make it possible to recover such "lost" variable stars. We will present our results on the recovery of eight "lost" variable stars, NY Cyg, VW Sgr, GW Sgr, GZ Sgr, HK Sgr, HT Sgr, HU Sgr, and HW Sgr, using plates of the Maria Mitchell Observatory collection. For the stars recovered, we will present accurate coordinates, improved classification and light elements. In one case, that of HW Sgr, we were able to reveal a definitely variable star approximately in the published position, but the character of its variability is in complete disagreement with the earlier data. Either the star was misclassified by the discoverer or the discoverer's position for HW Sgr is grossly in error, and we actually found another variable.

Ronald E Zissell
“What Magnitude is that Galaxy?”
The magnitude system that we use to rate the brightness of stars has major problems when applied to extended area objects such as galaxies or comets. The S10 brightness system gives a more realistic measure of an objects visibility in the telescope.

Tiffany Llenos & Mark Daranciang
“Na Hoku O Mililani - The Stars of Mililani”
Mark Daranciang and Tiffany Llenos, high school juniors, describe how the TOPS Summer Program, sponsored by the Institute for Astronomy (University of Hawaii and Mauna Kea Observatories), introduced them to the delights of variable star observing. They contribute data to the AAVSO from the Pacific region and are embarking on an ambitious project to involve other Mililani residents in variable star astronomy.

Christopher B. Sande, Wayne H. Warren Jr., & David A. Tracewell
“Recent Enhancements to and Future Plans for the SKY2000 Star Catalog”
Our continuing efforts to improve the NASA SKY2000 satellite attitude determination star catalog, previously known as SKYMAP, to make it into a modern, high-quality comprehensive source of stellar data, have allowed us to complete Version 3 of the SKY2000 catalog (June, 2000). The present version of the catalog contains 299,160 entries and is reasonably complete to visual magnitude 9. As with previous versions of the SKY2000 and SKYMAP catalogs, the most important data in the catalog are astrometry and photometry, because this information is essential for spacecraft attitude determination and control. Accurate information on multiplicity, spectral-type and luminosity class, and variability are also required to predict what the star trackers will detect. The SKY2000 Version 3 catalog marks the global replacement of the Henry Draper (HD) spectral type data, as well as the global replacement of the photovisual (ptv) and photographic (ptg) magnitude data. During this process, 4,684 entries had HD or HD Extension (HDE) identifiers added, for a total of 210,062 entries with HD/HDE identifiers. A planned global replacement of variable-star names/identifiers and variability data was not carried out because of resource constraints, but 311 variable-star names/identifiers were added during analysis, bringing the total number of entries with variable star names or identifiers to 2,575.

The next planned update to the SKY2000 catalog will include a global replacement of variable-star names/identifiers and variability data. Catalogs to be utilized will include, but are not limited to, the General Catalogue of Variable Stars (GCVS) and the New Catalog of Suspected Variable Stars (NSV). Completion of this updated version of the SKY2000 catalog is anticipated in spring, 2001. We intend to eventually utilize the AAVSO database to incorporate the highest quality data periods and amplitudes, particularly for long-period variables, but this may not be possible for the next enhancement.

This paper describes the current status after recent enhancements of the SKY2000 catalog and outlines plans for future improvements. This edition (SKY2000, version 3) and future editions of the catalog will be made available at Goddard's Flight Dynamics Web site: http://cheli.gsfc.nasa.gov/dist/attitude/skymap.html.

George Hawkins
“Chart Making for the AAVSO CCD Program”
The AAVSO CCD observing program currently includes charts for 39 CVs and LPVs with minima too faint for visual observations. In this talk, I report on the status of making CCD charts from photometric sequences observed at Mt. Holyoke and Lowell observatories. I discuss how the CCD charts are made, including data reduction, selecting comparison stars, and the automatic IDL program that makes the charts. I will also comment on future plans for an automatic program that can make charts for any part of the sky on demand, using pre-existing images or star catalogs, and a database of photometric standards. CCD light curves of a few stars in the program will be shown and compared to visual observations.

David Turner
“Characteristics of the Variable Star P Cygni Determined from Cluster Membership”
Available observational evidence suggests that the variable B2 Oe supergiant P Cygni is a likely member of the sparse anonymous cluster in which it lies, and is perhaps also associated with the spatially adjacent cluster IC 4996, which may be a companion cluster to the P Cygni cluster. If P Cygni is indeed a cluster member, as argued by radial velocity and reddening data, then its intrinsic properties are much better established empirically than has been the case previously. Evidence for high luminosity of P Cygni is confirmed by a derived absolute magnitude of Mv = -8.46±0.03, which translates into log (L/L¤) = 5.59±0.05 for an effective temperature consistent with the star’s derived space reddening (EB-V = 0.53±0.02). More surprising is an age for the associated cluster of 8 (±1) X 106 years, which corresponds to a turnoff point mass of 20.4 M¤. By inference, P Cygni, as a post main-sequence object, should have a mass of no more than about 20-25 M¤, as compared to estimates of ~30 M¤ derived in previous studies. The implied progenitor to P Cygni was therefore a main-sequence O-type star of spectral type 07-08, or possibly a massive binary system, given that the star’s present luminosity is very close to the upper limit for a single star evolution at an age of 8 million years. The possibility that P Cygni represents a merged binary system is consistent with the star’s membership in a dynamically evolved open cluster.