%R 1997PASP..109.1193S
%J-1214
%T The Mount Wilson Halo Mapping Project 1975-1985. I. The UBV(RI)_MW_ Photometric System Compared with Other Standard
Systems: The Adopted Trigonometric Hr Diagram in (R-I)_MW_ and (V-I)_MW_
%A SANDAGE A.
%F contents_97_11
%K Stars
%B \begin{tex}Photometry of stars is described that defines a UBV(RI)$_M_W$ photometric system, established between 1975 and 1980
using the Mount Wilson 60-inch and 100-inch reflectors. The MW natural system has been reduced to the UBV(RI)$_C$
Cape-Cousins system by linear equations for stars hotter than M0. Strong non-linear color and magnitude equations exit
in R and I between the two systems for stars cooler than M0. The non-linearity is due to the change of the effective
wavelengths of the red passbands caused by effect of the TiO b ands combines with the substantial difference between red
response of the extended S20 cathodes used here and the GaAs cells used by Cousins (1976, 1980a,b), Bessell (1979,
1990), Landolt (1983, 1992), and others for the Cape system. We report (R-I)$_M_W$ and (V-I)$_M_W$ colors based on a
linear extension of the $_M_W$ natural system to the red for cool stars with (V-R)$_Cape$ greater than 0.8, (V-I)$_Cape$
greater than 1.8 (spectral types later than M0), as zero-pointed to the Cape system for bluer stars. Color equations are
derived between the MW, the Cape, the Kron-Eggen, and Johnson photometric systems, and also the Hubble Space Telescope
(V-I) colors as reduced to the (V-I)$_C$ Cape system by Holtzman et al. (1995). The Kron-Eggen and the Cape-Cousins R
and I systems differ in their zero points of color and magnitudes, showing that the Kron-Eggen and the Cousins systems
are not the same. The appellation of a "Kron-Cousins" photometric system used in much of the current literature is
incorrect. Preparatory to determining photometric parallaxes of local higher proper motion M dwarfs in Paper IV,
trigonometric HR diagrams are determined in V, (V-R)$_M_W$ and (V-I)$_M_W$ on the Mount Wilson system using 160
available parallax stars with parallaxes larger than 0.099 arcsec. A first appendix illustrates the difference in the
effective wavelengths of the Cape-Cousins, Kron-Eggen, and Johnson systems for cool stars, based on the observed slope
coefficients of the color equations that link them. A second appendix contains explicit color equations based on stars
in common between Bessell's (1990) definition of the Cape system for the reddest stars and the Kron-Eggen and the MW
photometric systems.
\end{tex}

%R 1997PASP..109.1215P
%J-1220
%T Photometric Monitoring of Bright Be Stars. iii. 1988-89 and 1992-95
%A PERCY J.R., HARLOW J., HAYHOE K.A.W., IVANS I.I., LISTER M., PLUME R., ROSEBERY T., THOMPSON S., YEUNG D.
%F contents_97_11
%K Stars
%B We report long-term photometric (BV) observations of 23 bright, active Be stars made in 1988 and 1989 and 1992 and
1995 with the 0.4m telescope at the University of Toronto. Cumulative light curves, including observations made earlier
at the University of Toronto, and with the Automatic Photometric Telescope Service in Arizona, are presented for several
of the stars. Many of the stars show cyclic variations of up to 0.2 in V and B on time scales of a few years, as well as
variations on time scales of about a day.

%R 1997PASP..109.1221M
%J-1232
%T Luminosities of Sx Phoenicis, Large-Amplitude Delta Scut, and Rr Lyrae Stars
%A MCNAMARA D.
%F contents_97_11
%K Stars
%B \begin{tex}Str\ddot{o}mgren $_uvby$\beta photometry of SX Phoenicis and large-amplitude \delta Scuti variables is analyzed to
determine the mean temperatures, metal abundances, and surface gravities of the stars. The mean temperatures and
fundamental periods are used in conjunction with the pulsation equation and stellar models to derive masses, radii,
surface gravities, and $M_bol$ of the variables. The stars exhibit a period-luminosity relation. With the aid of
Hipparcos trigonometric parallaxes the zero-point of the $M_v, p$ is set. We find $M_v$ = -3.725 log $P$ - 1.933. This
P-L relation is utilized to find the $M-v$ values of RR Lyrae stars or horizontal-branch stars in globular clusters and
the Carina galaxy-objects that contain both SX Phe, and RR Lyrae variables, or horizontal-branch stars. The $M_v$ values
of the metal-ppor RR Lyrae stars are found to be consistent with $M_v$ [Fe/H] calibrations derived by Sandage (1993) and
by McNamara (1997) from revised Baade- Wesselink $M_v$ values. At [Fe/H] = -1.9 $M_v$ is 0.42. Feast and Catchpole
(1997) suggestion that $M_v$ = 0.25 at [Fe/H] = -1.9 for RR Lyrae is discussed. This $M_v$ vlue is too luminous because
it makes the (T$_eff$) of RR Lyraes too high-well off any (T$_eff$) = $_f$ (color index)
\end{tex}

%R 1997PASP..109.1233G
%J-1236
%T M Subdwarf Secondaries: A Test of the Metallicity Scale
%A GIZIS J., REID I.
%F contents_97_11
%K Stars
%B \begin{tex}We present spectra of three M subdwarfs which are common proper motion companions to F or G subdwarfs of known
metallicity. The assumption that the companions have the same composition allows us to test the Gizis (1997, \aj, 113,
806) M subdwarf classification system and its correspondence to metallicity. The results are in excellent agreement with
the Gizis (1997) scale, thereby showing that the Allard \& Hauschildt (1995, \apj, 445, 433) Extended model atmospheres
agree well in the 6200 -- 7400$\AA$ region for cool metal-poor stars. We also show that the results are consistent with
the main sequences of globular clusters using the Reid (1997, \aj, in press) distance scale.
\end{tex}

%R 1997PASP..109.1237S
%J-1240
%T The Interacting Eclipsing Binary AU Monocerotis Revisited
%A SAHADE J., FERRER O., GARCIA L.G., BRANDI E., BARBA R.
%F contents_97_11
%K Stars
%B New spectrographic observations of the Algol binary AU~Monocerotis have permitted the determination of the orbital
elements of the two components of the system. They have further suggested that the image tube spectrograph that was
attached to the CTIO 1m-reflecting telescope in 1978 and 1979 was not quite suitable for radial velocity work.

%R 1997PASP..109.1241T
%J-1245
%T Orbital Periods for the Cataclysmic Binaries Vz Pyxidis, Cc Cancri, and Ah Eridani
%A THORSTENSEN J.R.
%F contents_97_11
%K Stars
%B \begin{tex}This paper gives mean spectra and reports orbital periods based on radial velocities taken near minimum light for
these dwarf novae, which are all SU UMa stars or candidates. For VZ Pyx I find $P_{\rm orb} = 0.07332 \pm 0.00003$ d (=
$105.58 \pm 0.04$ min), for CC Cnc $0.07352 \pm 0.00005$ d (= $105.86 \pm 0.07$ min), and for AH Eri, $0.2391 \pm
0.0005$ d (= $5.738 \pm 0.012$ hr). In AH Eri's case orbital frequencies differing by $\pm 1$ cycle d$^{-1}$ are
marginally possible. The period for VZ Pyx is similarly ambiguous, but Kato and Nogami's \markcite{knvz} (1997a)
superhump period and Remillard et al.'s \markcite{rem94} (1994) short time base velocity study constrain the alias
choice to a single value. For CC Cnc, a preliminary measurement by Munari et al. \markcite{mun} (1991) had indicated a
$P_{\rm orb}$ in the 2 to 3 hour period `gap', but the $P_{\rm orb}$ found here is well short of the gap. AH Eri had
been mentioned in the literature as a possible SU-UMa type dwarf nova; the long period found here makes this
classification doubtful. The average spectrum of AH Eri shows molecular absorption bands consistent with an M-type
secondary star. With the orbital periods in hand, it would now be interesting to obtain new timeseries photometry aimed
at confirming or refuting the candidate $\sim 40$ min photometric modulations in AH Eri and VZ Pyx which have been put
forth in the literature.
\end{tex}

%R 1997PASP..109.1246S
%J-1250
%T CN and CH Band Strengths of Bright Giants in the Globular Cluster M10
%A SMITH G., FULBRIGHT J.
%F contents_97_11
%K Stellar Clusters and Associations
%B \begin{tex}The pattern of spectroscopic CN and CH band strengths among red giants in M10 is found to be similar to that seen in
other globular clusters. Two groups of stars, CN-strong and CN-weak, can be discerned on the upper giant branch. Spectra
obtained at Lick observatory of 10 such giants show that the CH and CN band strengths are anticorrelated, with
star-to-star differences being apparent in both the $\lambda$3883 and $\lambda$4215 CN bands. Combining the Lick data
with the [O/Fe] abundances measured by Kraft et al. (1995, AJ, 109, 2586) shows that the CN band strength is
anticorrelated with [O/Fe]. With respect to these abundance peculiarities, as well as the [Fe/H] metallicity, M10 is
similar to the clusters M3 and M13. One distinction between these clusters is the fraction of giants that show CN
enhancements; within M10 CN-strong giants are in the minority by a ratio of almost 1:2 (CN-strong :CN-weak), whereas in
M13 strong CN bands are found among a much larger percentage of giants.
\end{tex}

%R 1997PASP..109.1251C
%J-1263
%T The Symmetry, Color, and Morphology of Galaxies
%A CONSELICE C.J.
%F contents_97_11
%K Galaxies
%B \begin{tex}The structural symmetry of forty-three face-on galaxy images in the R(650 nm) and J(450 nm) bands are measured to
determine the usefulness of symmetry as a morphological parameter. Each galaxy image is rotated by $180$\deg and
subtracted from the original to obtain a quantitative value for its structural symmetry. The symmetry numbers computed
for the sample are then compared with RC3 morphological types, color \& absolute blue magnitudes. A strong correlation
between color and symmetry is found, and the RC3 Hubble sequence is found to be one of increasing asymmetry. The use of
symmetry as a morphological parameter, and the possible causes of the asymmetries are discussed.
\end{tex}

%R 1997PASP..109.1256Z
%J-1263
%T Remote Observing at the ESO NTT \& CAT Telescopes
%A ZIJLSTRA A., WALLANDER A., KAPER L., RODRIQUEZ J.A.
%F contents_97_11
%K Astronomical Instrumentation
%B Remote observing can be broadly defined as those observations carried out by an astronomer who is not physically
present at or near the telescope. At the European Southern Observatory, remote observing from the headquarters in
Germany to La Silla in Chile is offered for the 1.4m CAT and the 3.5m NTT, using a dedicated satellite link. During 1995
and 1996 the remote observing facility was successfully used for about 50\% (CAT) and 20\% (NTT) of the available
observing time. In this paper, we describe aspects related to the effiency of remote observing for scientific
observations. The support structure at ESO headquarters is described, as experienced by the observers. Observing
efficiencies are calculated: with the present system, we find that observing efficiencies are the same for local and
remote observing within the uncertainties, for most types of observations. Few projects still require local
observations. Some of the feedback provided by the observers is described.

%R 1997PASP..109.1264M
%J-1268
%T Stardial: An Autonomous Astronomical Camera on the World Wide Web
%A MCCULLOUGH P., THAKKAR U.
%F contents_97_11
%K Astronomical Instrumentation
%B We describe the use of an autonomous astronomical camera, called ``Stardial,'' for undergraduate instruction.
Stardial\footnote{The name ``Stardial'' derives from the fact that like a sundial, Stardial is a stationary device
placed outside 24 hours a day, and that both depend on and make evident the rotation of the Earth. A sundial operates
with sunlight, while Stardial operates with starlight. There the similarity ends.} delivers images of the night sky
nearly in real-time to the world wide web (www.astro.uiuc.edu/ stardial/). The world wide web (WWW) interface is robust,
inexpensive, and accommodates many students asynchronously with respect to the instructor(s). The guiding philosophy is
to provide students with authentic astronomical data so that they may learn about science by doing it themselves.
Students respond favorably to the opportunity to learn from their own experiences with authentic data, complete with its
irregularities and its surprises. Stardial has been operational for one academic year (1996-97) at the University of
Illinois at Urbana-Champaign. In this paper we describe Stardial's instrumentation, some of the curriculum based upon
Stardial's unique data, and the experiences of students who have used Stardial. We conclude with possible research
topics using Stardial data and with a brief look to the future of remote laboratories.

%R 1997PASP..109.1269W
%J-1277
%T Recontructing Flat Fields from Non-Uniform Background Illumination Sources
%A WILD W.
%F contents_97_11
%K Astronomical Instrumentation
%B Precision CCD photometry over large fields-of-view and detection of very faint or diffuse objects demand great care
in the acquisition of flat-field frames. Variations in the illuminated field, either in the sky or with locally
illuminated dome screens, will introduce spatial variability, or gradient structure, in the flat field frame. This is a
concern for the Hubble Space Telescope which cannot make use of twilight or dome flats. The physics of generating
flat-field frames must account for the characterisitics and structure of the CCD, the instrument and telescope optics,
and the illumination source. Recognizing that small angular displacements of the CCD, telescope, and instrument, with
respect to the external light source (dome, sky, etc.) yields a corresponding linear translation of the image on the CCD
with respect to the true flat-field function, we can derive a functional equation that can be solved and hence enables a
flat-field frame to be generated that is indepenedent of the illumination source. This equation can be generalized to
two-dimensions approximating an elliptic partial differential equation relating the offset CCD measurements to the
flat-field function. This technique may benefit faint deep-field photometric wide field-of-view observations, the HST,
and cameras on spacecraft and planetary landers.

%R 1997PASP..109.1278S
%J-1284
%T Trends in Astronomical Publication Between 1975 and 1996
%A SCHULMAN E., FRENCH J.C., POWELL A.L., EICHHORN G., KURTZ M.J., MURRAY S.S.
%F contents_97_11
%K Astronomical Sociology
%B Trends in astronomical publication have traditionally been studied by examining the few thousand papers published in
a few selected journals within a few selected years. With the development of comprehensive bibliographic databases such
as ADS and SIMBAD, publication trends can now be studied using tens of thousands of papers published in a number of
refereed astronomy journals. The ADS has extensive bibliographic information on almost every paper published in seven
major astronomy journals over the past two decades; the SIMBAD database can be used to verify critical bibliographic
information such as the number of authors and the length of the papers. Here we present results of a study of
astronomical publication trends using 76,000 papers published in A\&A, A\&AS, AJ, ApJ, ApJS, MNRAS, and PASP between
1975 and 1996. Two trends are particularly interesting: the fraction of single-author papers has decreased by about a
factor of three in the last twenty years, while astronomical papers with more than fifty authors have become
increasingly common since 1990.

%R 1997PASP..109.1285E
%J-1285
%T Spectroscopic and Photometric Analysis of Novae: A New Classification Method
%A ESENOGLU H.
%F contents_97_11
%K Dissertation Summaries
%B \begin{tex}This study deals with the relationship between the absolute visual magnitude at maximum and the rate of decline (MMRD
or $M_v$ -- $t_3$) for classical novae. Considering the most reliable data including the nebular expansion parallax
method for 24 galactic novae, we find that there are two distinct kinds of galactic novae. Slopes of very fast and fast
novae were found from a least-squares fit to their MMRD relation. The values of these two slope angles are similar. A
similar result was found for moderately fast and slow novae, whose mean slopes differ by only a small amount. Therefore
very fast novae can be grouped with fast novae, and moderately fast novae can be grouped with slow novae, so that we
have only two separate novae groups. These two groups of novae are distinguished from each other by the Eddington
luminosity. Our conclusions agree well with those of Duerbeck (1981, PASP, 93, 165), based on the light curves of
approximately 100 galactic novae. Considering numerical nova model calculations (Livio 1992, ApJ, 393, 516), it seems
that there is a good agreement between the observed and the theoretical MMRD relation. Moreover, we applied the same
classification method to novae in M31 (Massimo and Livio, 1995, ApJ, 452, 704), and found the same two separate groups.
We also determined expansion parallaxes for QZ Aur, V1974 Cyg, FH Ser, XX Tau, RW UMi, and QU Vul, and expansion
velocities for Nova Aql 1995, V1974 Cyg and FH Ser. These results were found from H-alpha imaging and spectroscopic
observations made by the author and A.Bianchini and T.Iijima (University of Padova), using the 1.82- and 1.22-m
telescopes at the Ekar and Asiago Observatories. When we compare our images with those in the literature, we can obtain
expansion parallaxes for QU Vul, QZ Aur, V1974 Cyg, and RW UMi. Shell diameters in the light of H-alpha for QU Vul, QZ
Aur, V1974 Cyg and RW UMi were found to be 0.82, 0.83, 0.76 and 2.94 arcsec, respectively (epoch 1994-5). The literature
gives nebular expansion parallaxes for 22 galactic novae. To these we can now add expansion parallaxes for QZ Aur and QU
Vul, thus increasing the number to 24. Two high-dispersion spectra of FH Ser and N Aql 1995, and a low-dispersion
spectrum of V1974 Cyg, give the following expansion velocities: $425 \pm 25$, $675 \pm 25$, and $1600 \pm 100$ km/s,
respectively. 
\end{tex}

%R 1997PASP..109.1286M
%T The Circumstellar Environment of Evolved Stars as Revealed by Studies of Circumstellar Water Masers
%A MARVEL K.B.
%F contents_97_11
%K Dissertation Summaries
%B \begin{tex}This dissertation presents the results of a multi-epoch very long baseline interferometric (VLBI) study of water
masers located in the extended atmospheres of seven evolved stars. The research was performed using the Very Long
Baseline Array and Very Large Array of the National Radio Astronomy Observatory. Water masers are found to exist in the
atmospheres of evolved, oxygen-rich stars where a population inversion of the rotational transition at 22 GHz can be
maintained by collisional pumping. The masers are identified as individual pockets or filaments of gas, which have good
velocity coherence and may be imaged using radio interferometry. Stellar winds are initiated in these sources by dust
formation and acceleration of the gas through momentum coupling. The typical wind speeds in the region of the water
masers are 10 to 20 \kms. The water masers in several evolved stars (VY CMa, VX Sgr, S Per, U Her, IK Tau , RX Boo and
NML Cyg) have been observed at three epochs and exhibit proper motions consistent with the assumed source distances and
the measured outflow velocity in the water maser region. Estimates of the distance to the sources using statistical
approximation are in agreement with the currently accepted distances to the stars. The following stars had reliable
distances determined using proper motion data: S Per ($2.3 \pm 0.5$ kpc), VY CMa ($1.4 \pm 0.2$ kpc), VX Sgr ($1.4 \pm
0.3$ kpc). An upper limit for the distance of NML Cyg was obtained ($ 3.5$ kpc). The remaining stars had too few maser
detections (RX BOO, IK Tau) or were not strong enough at all epochs (U Her) to self-calibrate using the VLBA. A detailed
kinematic model was used to describe the flow motions of the gas in the maser region. The regions are found to be
complex and not well modeled by uniform radial outflow, radial outflow with rotation, or radial outflow with
acceleration. The reasons for this are explored and include the probable presence of anisotropic velocity fields induced
through non-uniform dust formation near the star.
\end{tex}