We present an updated O-C diagram of the light-time variations of the eclipsing binary (component B) in the system QZ Carinae as it moves in the long-period orbit around the non-eclipsing pair (component A). This includes new Variable Stars South members' measures from 2017 to 2019, BRITE satellite observations in 2017 and 2018, and 100 previously unpublished measures made at Auckland Observatory from 1974 to 1978. We conclude that QZ Carinae has not yet completed one orbit of the two pairs since discovery in 1971. The duration of totality of primary eclipses was measured to be 0.295 +/- 0.02 day (7.08 +/-0.48 hours), rather longer than earlier values from light curve models. Other observational findings include the shape of primary and secondary eclipses and small-scale short-term brightness changes.

The illustration above is an artist’s idea of how a CV (dwarf nova) system appears. It comprises a white dwarf star with a radius of perhaps 20,000 kilometres and a rather small normal star, usually about 10 to 30 times that size which is losing material from its surface due to gravitational interaction. The angular momentum ensures that in most cases this material forms a disc around the white dwarf star from which most will, in due course, fall onto the WD but some will be lost from the system entirely.

V1432 Aquilae is the only known eclipsing asynchronous polar. In this respect it is unique and therefore merits our attention. We report the results of a 15-year campaign by the globally distributed Center for Backyard Astrophysics to observe V1432 Aql and investigate its return to synchronism. Originally knocked out of synchrony by a nova explosion before observing records began, the magnetic white dwarf in V1432 Aql is currently rotating slower than the orbital period but is gradually catching up. The fortuitously high inclination of the binary orbit affords us the bonus of eclipses providing a regular clock against which these temporal changes can be assessed. At the present rate, synchronism should be achieved around 2100. The continually changing trajectory of the accretion stream as it follows the magnetic field lines of the rotating white dwarf produces a complex pattern of light emission which we have measured and documented, providing comprehensive observational evidence against which physical models of the system can be tested.

s, JAAVSO Volume 40, 2012 177 The RASNZ Photometry Section, Incorporating the Auckland Photoelectric Observers’ Group (Poster abstract) Stan Walker 272 Heath Road, Waiharara 0486, New Zealand; astroman@paradise.net.nz Presented at the 100th Annual Meeting of the AAVSO, October 8, 2011 Abstract This review traces the development of amateur photoelectric and CCD photometry in New Zealand from its beginnings in the late 1960s at Christchurch and Auckland, through the Auckland Photoelectric Observers’ Group and the RASNZ Photometry Section to its present place in Variable Stars South. For this period of over forty years the participants have been heavily involved with southern hemisphere variable star astronomy and observatories such as Carter, Mt. John, and Auckland, together with which were sponsored the highly successful photoelectric conferences, PEP 1-5. Samples of various projects are shown and described. The full text can be seen at http://www. variablestarssouth.org/index.php/community/member-publications/posters This review traces the development of amateur photoelectric and CCD photometry in New Zealand from its beginnings in the late 1960s at Christchurch and Auckland, through the Auckland Photoelectric Observers’ Group and the RASNZ Photometry Section to its present place in Variable Stars South. For this period of over forty years the participants have been heavily involved with southern hemisphere variable star astronomy and observatories such as Carter, Mt. John, and Auckland, together with which were sponsored the highly successful photoelectric conferences, PEP 1-5. Samples of various projects are shown and described. The full text can be seen at http://www. variablestarssouth.org/index.php/community/member-publications/posters Introduction to BAV (Abstract) Franz-Josef Hambsch Joachim Hübscher address correspondence to J. Hambsch, Oude Bleken 12, Mol 2400, Belgium; hambsch@telenet.be Presented at the 100th Annual Meeting of the AAVSO, October 5, 2011 Abstract The Bundesdeutsche Arbeitsgemeinschaft für Veränderliche Sterne was founded 1950 in Berlin. The intention was—and still is—to support amateurs in the systematic observation of variable stars. The history of the German workgroup, the classical working focus (maxima and minima and single estimates), and the main publications (BAV Mitteilungen and LichtenkneckerDatabase of the BAV) will be described.The Bundesdeutsche Arbeitsgemeinschaft für Veränderliche Sterne was founded 1950 in Berlin. The intention was—and still is—to support amateurs in the systematic observation of variable stars. The history of the German workgroup, the classical working focus (maxima and minima and single estimates), and the main publications (BAV Mitteilungen and LichtenkneckerDatabase of the BAV) will be described. The GEOS Association of Variable Star Observers (Abstract) Franz-Josef Hambsch J. -F. Le Borgne E. Poretti the GEOS association address correspondence to J. Hambsch, Oude Bleken 12, Mol 2400, Belgium; hambsch@telenet.be Presented at the 100th Annual Meeting of the AAVSO, October 5, 2011 Abstracts, JAAVSO Volume 40, 2012 178s, JAAVSO Volume 40, 2012 178 Abstract Groupe Européen d’Observation Stellaire (GEOS) is an astronomical association created in the 1970s to promote research among amateurs in Europe. We started in Belgium, France, and Italy, later extended to Spain, Switzerland, and Germany, and more recently, added U.S. amateurs. The basic idea was that amateurs should themselves extract scientific information from their observations (visually at first and later electronically) and publish their results. Some GEOS members have become professional astronomers and the amateurprofessional collaboration has strengthened over the years. From the beginning, it has been clear that the study of variable stars is a privileged topic where such projects can develop. Since the 1980s GEOS members have published a number of scientific papers, even in refereed professional journals. Presently, observations are mainly done using CCD cameras though visual measurements still exist. In the past decade our main development has been the creation of a public RR Lyr star maxima database. This is a unique tool for the study of RR Lyr stars, as it enables the user to follow period variations since a star’s discovery, some over 100 years ago. In parallel to the database, a project called “GEOS RR Lyr survey” was designed. Its aims include: first, add significantly more maxima timings of the brightest RR Lyr stars essentially using robotic telescopes; second, study fainter understudied stars to refine their period and find new stars which exhibit the so-called Blazhko effect; third, characterize the Blazhko effect, one of our main research topics. Other variable stars are also studied: eclipsing binaries, d Scuti stars, and so on. GEOS has a good cooperation with other variable star associations, mainly BAV and AAVSO.Groupe Européen d’Observation Stellaire (GEOS) is an astronomical association created in the 1970s to promote research among amateurs in Europe. We started in Belgium, France, and Italy, later extended to Spain, Switzerland, and Germany, and more recently, added U.S. amateurs. The basic idea was that amateurs should themselves extract scientific information from their observations (visually at first and later electronically) and publish their results. Some GEOS members have become professional astronomers and the amateurprofessional collaboration has strengthened over the years. From the beginning, it has been clear that the study of variable stars is a privileged topic where such projects can develop. Since the 1980s GEOS members have published a number of scientific papers, even in refereed professional journals. Presently, observations are mainly done using CCD cameras though visual measurements still exist. In the past decade our main development has been the creation of a public RR Lyr star maxima database. This is a unique tool for the study of RR Lyr stars, as it enables the user to follow period variations since a star’s discovery, some over 100 years ago. In parallel to the database, a project called “GEOS RR Lyr survey” was designed. Its aims include: first, add significantly more maxima timings of the brightest RR Lyr stars essentially using robotic telescopes; second, study fainter understudied stars to refine their period and find new stars which exhibit the so-called Blazhko effect; third, characterize the Blazhko effect, one of our main research topics. Other variable stars are also studied: eclipsing binaries, d Scuti stars, and so on. GEOS has a good cooperation with other variable star associations, mainly BAV and AAVSO. History of Amateur Variable Star Observations in Japan (Poster abstract) Seiichiro Kiyota Variable Star Observers League in Japan (VSOLJ), c/o Keiichi Saijo National Science Museum, Ueno-Park, Tokyo Japan; e-mail:skiyotax@gmail.com Presented at the 100th Annual Meeting of the AAVSO, October 8, 2011 Abstract Japan has about 100 years of history of variable star observing since Naozo Ichinohe, professional astronomer in Tokyo Observatory, observed d Cep in 1906. The first amateur variable star observer is Yoshihiko Kasai, who began observing variable stars in 1918. I introduce a brief history of Japanese amateur variable star observation, including topics of variable star organizations, nova and supernova hunters, collaborations with the AAVSO and the world, PEP and CCD observations. I also introduce the most active variable star observer, Hiroaki Narumi, who made over 260,000 visual estimates since 1975. VSOLJ was established in 1987 in collaborations with the variable star sections of Nihon Tenmon Kenkyu-kai (NTK) and the Oriental Astronomical Association (OAA). VSOLJ maintains a database of Japanese variable star observations (http://vsolj.cetus-net.org) and publishes the Variable Star Bulletin in English. Japan has about 100 years of history of variable star observing since Naozo Ichinohe, professional astronomer in Tokyo Observatory, observed d Cep in 1906. The first amateur variable star observer is Yoshihiko Kasai, who began observing variable stars in 1918. I introduce a brief history of Japanese amateur variable star observation, including topics of variable star organizations, nova and supernova hunters, collaborations with the AAVSO and the world, PEP and CCD observations. I also introduce the most active variable star observer, Hiroaki Narumi, who made over 260,000 visual estimates since 1975. VSOLJ was established in 1987 in collaborations with the variable star sections of Nihon Tenmon Kenkyu-kai (NTK) and the Oriental Astronomical Association (OAA). VSOLJ maintains a database of Japanese variable star observations (http://vsolj.cetus-net.org) and publishes the Variable Star Bulletin in English.

We systematically surveyed period variations of superhumps in SU UMa-type dwarf novae based on newly obtained data and past publications. In many systems, the evolution of the superhump period is found to be composed of three distinct stages: an early evolutionary stage with a longer superhump period, a middle stage with systematically varying periods, and a final stage with a shorter, stable superhump period. During the middle stage, many systems with superhump periods of less than 0.08 d show positive period derivatives. We present observational characteristics of these stages and give greatly improved statistics. Contrary to an earlier claim, we found no clear evidence for a variation of period derivatives among different superoutbursts of the same object. We present an interpretation that the lengthening of the superhump period is a result of the outward propagation of an eccentricity wave, which is limited by the radius near the tidal truncation. We interpret that late-stage superhumps are rejuvenated excitation of a 3:1 resonance when superhumps in the outer disk are effectively quenched. The general behavior of the period variation, particularly in systems with short orbital periods, appears to follow a scenario proposed in Kato, Maehara, and Monard (2008, PASJ, 60, L23). We also present an observational summary of WZ Sge-type dwarf novae. Many of them have shown long-enduring superhumps during a post-superoutburst stage having longer periods than those during the main superoutburst. The period derivatives in WZ Sge-type dwarf novae are found to be strongly correlated with the fractional superhump excess, or consequently with the mass ratio. WZ Sge-type dwarf novae with a long-lasting rebrightening or with multiple rebrightenings tend to have smaller period derivatives, and are excellent candidates for those systems around or after the period minimum of evolution of cataclysmic variables.

We report precise measures of the orbital and superhump period in 20 more dwarf novae. For 10 stars, we report new and confirmed spectroscopic periods-signifying the orbital period P-o-as well as the superhump period P-sh. These are GX Cas, HO Del, HS Vir, BC UMa, RZ Leo, KV Dra, KS UMa, TU Crt, QW Ser, and RZ Sge. For the remaining 10, we report a medley of P-o and P-sh measurements from photometry; most are new, with some confirmations of previous values. These are KV And, LL And, WX Cet, MM Hya, AO Oct, V2051 Oph, NY Ser, KK Tel, HV Vir, and RX J1155.4-5641.Periods, as usual, can be measured to high accuracy, and these are of special interest since they carry dynamical information about the binary. We still have not quite learned how to read the music, but a few things are clear. The fractional superhump excess epsilon[= (P-sh - P-o)/P-o] varies smoothly with P-o. The scatter of the points about that smooth curve is quite low, and can be used to limit the intrinsic scatter in M-1, the white dwarf mass, and the mass-radius relation of the secondary. The dispersion in M-1 does not exceed 24%, and the secondary-star radii scatter by no more than 11% from a fixed mass-radius relation. For the well-behaved part of epsilon(P-o) space, we estimate from superhump theory that the secondaries are 18% +/- 6% larger than theoretical ZAMS stars. This affects some other testable predictions about the secondaries: at a fixed P-o, it suggests that the secondaries are (compared with ZAMS predictions) 40% +/- 14% less massive, 12% +/- 4% smaller, 19% +/- 6% cooler, and less luminous by a factor of 2.5(7). The presence of a well-defined mass-radius relation, reflected in a well-defined relation, strongly limits effects of nuclear evolution in the secondaries.

We report the results of a worldwide campaign to observe WZ Sagittae during its 2001 superoutburst. After a 23 yr slumber at V = 15.5, the star rose within 2 days to a peak brightness of 8.2, and showed a main eruption lasting 25 days. The return to quiescence was punctuated by 12 small eruptions, of ∼1 mag amplitude and 2 day recurrence time; these “echo outbursts” are of uncertain origin, but somewhat resemble the normal outbursts of dwarf novae. After 52 days, the star began a slow decline to quiescence. Periodic waves in the light curve closely followed the pattern seen in the 1978 superoutburst: a strong orbital signal dominated the first 12 days, followed by a powerful common superhump at 0.05721(5) day, 0.92(8)% longer than Porb. The latter endured for at least 90 days, although probably mutating into a “late” superhump with a slightly longer mean period [0.05736(5) day]. The superhump appeared to follow familiar rules for such phenomena in dwarf novae, with components given by linear combinations of two basic frequencies: the orbital frequency ωo and an unseen low frequency Ω, believed to represent the accretion disk’s apsidal precession. Long time series reveal an intricate fine structure, with ∼20 incommensurate frequencies. Essentially all components occurred at a frequency nωo - mΩ, with m = 1, …, n. But during its first week, the common superhump showed primary components at nωo - Ω, for n = 1, 2, 3, 4, 5, 6, 7, 8, 9 (i.e., m = 1 consistently); a month later, the dominant power shifted to components with m = n - 1. This may arise from a shift in the disk’s spiral‐arm pattern, likely to be the underlying cause of superhumps. The great majority of frequency components are redshifted from the harmonics of ωo, consistent with the hypothesis of apsidal advance (prograde precession). But a component at 35.42 cycles day−1 suggests the possibility of a retrograde precession at a different rate, probably N = 0.13 ± 0.02 cycles day−1. The eclipses permit measuring the location and brightness of the mass‐transfer hot spot. The disk must be very eccentric and nearly as large as the white dwarf’s Roche lobe. The hot‐spot luminosity exceeds its quiescent value by a factor of up to 60. This indicates that enhanced mass transfer from the secondary plays a major role in the eruption.

We report photometry of the helium-dominated cataclysmic variable HP Librae during 1995-2001. The main photometric signal varies between 1118.89 and 1119.14 s, on a timescale of a few years, and displays a waveform characteristic of "superhumps." After subtracting the main signal, we found a weak residual signal at s, which we interpret as the underlying orbital period of the binary. The full amplitude of this 1102.70+/-0.05 putative orbital variation is just 0.005 mag, the weakest orbital signal yet found in a cataclysmic variable (CV). The 1119 s signal of HP Lib is a superb match to the well-studied 1051 s superhump of AM CVn, the "mother of all helium CVs." The superhump shows no change in amplitude or waveform on any timescale and no essential change in period on timescales shorter than similar to3000 cycles. Such great stability makes the star a promising test case for detailed studies of the underlying spiral structure in the disk, the likely cause of superhumps. Comparison of orbital and superhump periods for the family of AM CVn stars supplies evidence that these stars are evolving toward longer orbital period.

We report 1992–1999 photometry of the helium‐rich cataclysmic variable V803 Centauri. In its high brightness state at V = 13, the star shows a strong periodic signal with P = 1618 s; this resembles the superhumps associated with many dwarf novae. However, it is unusual because the superhump appears to endure through all brightness states, including the very faint state at V = 17. The star also becomes occasionally stuck in a “cycling state,” in which the brightness varies in the range 13.4–14.5, with a period of 22 ± 1 hr. This appears to be the recurrence pattern of “normal” dwarf nova outbursts. Thus the underlying physics is probably that of a dwarf nova, but with an accretion disk dominated by helium. Reckoned as a dwarf nova, V803 Cen presents an interesting test for accretion disk theory, because it appears to display two timescales for eruption recurrence: 0.94 day at V = 14.5 and ∼5 days at V = 17.2. This is roughly consistent with the general idea that recurrence time scales inversely with accretion rate.