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Re: Software problem in time-series photometry > time-series photometry by certain software data reduction packages, such as > AIP4WIN. I'm a AIP4WIN user myself too, and did a quite detailed analysis of > the photometry accuracy of this package, before switching over from my > previous software tool to AIP4WIN. Yes, I presume that this is the reason why AIP4WIN is popularly used by our observers. > As a important side remark : you mention that you have encountered the > photometry problems quite frequently in the past weeks/months. Given the > amount of photometry data produced with AIP4WIN in VSNET campaigns, and > given the effects that the introduced errors have (e.g., systematic > appearance of hump-like features), then how does all of the above relate > to the recent announcements you have been making regarding short-term > variations in f.i. superhump periods of outbursting dwarf novae ? > Are some of these findings to be revisited, as a consequence of the above ? Quite frequently met problems. Having known that this happenes more frequently than would be expected, I try to examine the reported data as precisely as possible, and try to make a contact with the observer when the data don't look real. This is particularly true when there are simultaneous observations. There may have been, in some cases, that the software problem would have produced wrong results -- this probably needs to be verified particularly if the reported phenomenon matches my description of the observed systematic trends. Speaking of recent data, some data sets on NSV 09923 produced systematically faint magnitudes, which was not confirmed by an independent obseravation. The noise in O-C's in some stars were from systematic effects, since we were sometimes able to check them with later reported data (this is particularly true when raw images become available). In eclipsing dwarf novae, some data sets give unusually deep eclipses, some of which were not confirmed to be real by a comparison with other simultaneous data. They may be only remarkable detections of problems, but I don't know whether the same problem more frequently affected the data to a lesser degree. Regards, Taichi Kato
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