PDS 110 is a young disc-hosting star in the Orion OB1A association. Two dimming events of similar depth and duration were seen in 2008 (WASP) and 2011 (KELT), consistent with an object in a closed periodic orbit. In this paper, we present data from a ground-based observing campaign designed to measure the star both photometrically and spectroscopically during the time of predicted eclipse in 2017 September. Despite high-quality photometry, the predicted eclipse did not occur, although coherent structure is present suggesting variable amounts of stellar flux or dust obscuration. We also searched for radial velocity (RV) oscillations caused by any hypothetical companion and can rule out close binaries to 0.1Ms. Asearch of Sonneberg plate archive data also enabled us to extend the photometric baseline of this star back more than 50 yr, and similarly does not re-detect any deep eclipses. Taken together, they suggest that the eclipses seen in WASP and KELT photometry were due to aperiodic events. It would seem that PDS 110 undergoes stochastic dimmings that are shallower and of shorter duration than those of UX Ori variables, but may have a similar mechanism.

We report null results on a 2 year photometric search for outburst predictors in SS Cyg. Observations in Johnson Vand Cousins I were obtained almost daily for multiple hours per night for two observing seasons. The accumulated data are put through various statistical and visual analysis techniques, but we fail to detect any outburst predictors. However, analysis of 102 years of AAVSO archival visual data has led to the detection of a correlation between a long term quasi-periodic feature at around 1000-2000 days in length and an increase in outburst rate.

We report null results on a two year photometric search for outburst predictors in SS Cyg. Observations in Johnson V and Cousins I were obtained almost daily for multiple hours per night for two observing seasons. The accumulated data are put through various statistical and visual analysis techniques but fails to detect any outburst predictors. However, analysis of 102 years of AAVSO archival visual data led to the detection of a correlation between a long term quasi-periodic feature at around 1,000-2,000 days in length and an increase in outburst rate.

We report null results on a two year photometric search for outburst predictors in SS Cyg. Observations in Johnson V and Cousins I were obtained almost daily for multiple hours per night for two observing seasons. The accumulated data are put through various statistical and visual analysis techniques but fails to detect any outburst predictors. However, analysis of 102 years of AAVSO archival visual data led to the detection of a correlation between a long term quasi-periodic feature at around 1,000-2,000 days in length and an increase in outburst rate. Subject headings: Stars

We report CCD photometry and spectroscopy during 2006 outburst of the dwarf nova SDSS J102146.44+234926.3 (SDSS J1021). The photographic plates from the MAO, SAI and CrAO plate archives, which cover the position of the SDSS J1021, were inspected for the presence of previous outbursts. We also present the BVRcIc photometric calibration of 52 stars in SDSS J1021 vicinity, which have V-magnitude in the range of 11.21-17.23m and can serve as comparison stars. The large amplitude of the SDSS J1021 outburst of 7m, superhumps with a period below the ''period gap'', rebrightening during the declining stage of superoutburst, rarity of outbursts and obtained spectrum allow to classify this object as a WZ Sge type dwarf nova.

The cataclysmic variable ASAS J002511+1217.2 was discovered in outburst by the All‐Sky Automated Survey (ASAS) in 2004 September, and intensively monitored by AAVSO observers through the following 2 months. Both photometry and spectroscopy indicate that this is a very short period system. Clearly defined superhumps with a period of 0.05687 ± 0.00001 (1 σ) days (81.9 minutes) are present during the superoutburst, 5 to 18 days following the ASAS detection. We observe a change in superhump profile similar to the transition to "late superhumps" observed in other short‐period systems; the superhump period appears to increase slightly for a time before returning to the original value, with the resulting superhump phase offset by approximately half a period. We detect variations with a period of 0.05666 ± 0.00003 (1 σ) days (81.6 minutes) during the 4 day quiescent phase between the end of the main outburst and the single echo outburst. Weak variations having the original superhump period reappear during the echo and its rapid decline. Time‐resolved spectroscopy conducted nearly 30 days after detection and well into the decline yields an orbital period measurement of 82 ± 5 minutes. Both narrow and broad components are present in the emission‐line spectra, indicating the presence of multiple emission regions. The weight of the observational evidence suggests that ASAS J002511+1217.2 is a WZ Sge–type dwarf nova, and we discuss how this system fits into the WZ classification scheme.

We present multicolor CCD photometry of ASAS 002511+1217.2 for first 55 days of 2004 outburst.

We present time-series observations, spectra, and archival outburst data of a newly discovered variable star in Hercules, Var Her 04. Its orbital period, mass ratio, and outburst amplitude resemble those of the ugwz-type subclass of ugsu dwarf novae. However, its supercycle and outburst light curve defy classification as a clear ugwz. Var Her 04 is most similar to the small group of possible hydrogen-burning "period bouncers," dwarf novae that have passed beyond the period minimum and returned.