In the mailing list, emphasis has been put on finding new variables from TASS data. I have been looking at DS23 the other way, i.e. how many of the known variables show up as variables (WS > 1) in the data ?
There may be a number of obvious reasons why a designated variable appears to be a non-variable in the data: the position of the variable is not accurate enough (resulting in misidentification), it may be too faint, the amplitude may be too small, or it may not be varying at the time of the observations (EA's outside of eclipse, slowly varying stars like Mira's which were not observed long enough, etc.), or the variable turns out not be a variable at all ! Taken these reasons into account, one may then get some idea of the efficiency of the observation and reduction procedure (a topic for the engineering paper?).
I have tried to match GCVS stars (December 2001 version from the GCVS website) with the results from wsv3.pl on DS23. Stars separated by not more than 1' and not too faint were declared a match. Positions for some stars in the GCVS are in error by 3' and more (although not as many as used to be), so not all stars from DS23 which are designated variables will appear (I think e.g. XY Tau may be one of those). Also, it means that there may be misidentifications.
The lists below give the star number from the collected.big file, average V and I magnitude, WS-statistic, the distance to the designated star in arc seconds, and the designated star with type, magnitude and period details (when available). Here is the list:
32894 9.60V 9.45I 879.74 7 RW Mon EA/SD 9.26-11.51V 1.90609412 36488 10.53V 9.33I 277.57 14 BE Mon DCEP 10.19-10.88V 2.705510 55692 11.31V 10.88I 174.29 2 AG CMi EA/SD 10.9-11.9P 1.6645438 50325 9.37V 8.72I 127.53 13 UY Mon DCEPS 9.22-9.62V 2.39813 68187 12.33V 10.00I 29.60 3 ST CMi SRB 13.2-14.4P 190.: 32115 12.29V 11.09I 18.45 31 WW Mon DCEP 11.97-12.92V 4.66231 33718 13.07V 10.08I 5.85 7 V624 Mon LB 12.6-13.3V 33822 10.76V 9.73I 5.60 34 NS Mon EW/DW 10.6-11.1P 0.9399163 47151 12.15V 9.65I 3.86 55 IT Mon LB 13.5-14.8P 31133 10.85V 9.65I 3.29 25 CS Mon CEP 10.71-11.30V 6.7317 79409 12.02V 11.51I 1.80 1 AL CMi RRAB 12.-13.P 0.55050 42124 11.81V 11.04I 1.55 55 BF Mon M 13.5-<15.5P 283. 29407 12.30V 9.45I 1.29 11 V622 Mon LB 14.8-15.5B 35795 9.68V 9.33I 1.00 11 V588 Mon DSCTC 9.66-9.72V 0.11 25586 12.36V 12.05I 0.98 47 V538 Mon EA: 14.-15.5P 36069 10.28V 9.76I 0.95 23 V589 Mon DSCTC 10.27-(0.05)V 0.124 45778 12.12V 11.70I 0.83 14 FV Mon EA/SD 11.5-13.9P 7.51880 24713 12.17V 11.97I 0.62 48 GM Mon RRAB 13.5-14.5P 26801 11.58V 10.47I 0.60 46 DP Mon S: 13.8-15.0P 33810 10.61V 10.12I 0.46 6 NS Mon EW/DW 10.6-11.1P 0.9399163 66071 12.27V 12.04I 0.45 5 RY CMi EA/SD 11.9-14.9P 3.265211 30347 12.82V 12.19I 0.33 14 VX Mon EA/SD 12.8-14.3P 1.62967 57177 10.63V 10.06I 0.25 0 BX CMi EA 10.81-11.48V 40170 11.55V 11.16I 0.17 30 IS Mon EA/SD 11.5-13.5P 4.04761 58058 11.23V 10.61I 0.11 1 WX CMi M 11.0-15.8P 420.1 50762 9.93V 9.73I -1.41 14 V680 Mon RR 9.6-10.1P 31395 12.72V 9.39I -2.97 4 V587 Mon SRB 11.9-13.4:V 400.:
Most stars with WS < 1 are EA's. FV and IS Mon were not in eclipse at the time of observation, according to the GCVS ephemeris. RY CMi should have been in mid-eclipse at JD 2452264.77, at the moment observations started (no eclipse on the other 5 nights - perhaps check a more recent ephemeris ?). For VX Mon mid-eclipse occured at JD 2452287.68, again just before observations started (no eclipse on the other night). For V538 Mon and BX CMi, a period is not known. V589 Mon is a low amplitude delta Scuti, and so variability detection is near its limit. However, the data themselves clearly show the variability and the timescale fits the GCVS period (there are only two nights of observations, not enough to determine a period). WX CMi is a Mira which should have been near its minimum according to AAVSO predictions, so there may be a misidentification despite the very small "error" in position (I should probably check the AAVSO chart). DP, GM and V538 Mon are on the faint site, and the positions do not match very well (this should be checked further with identification charts, if they exist). Also, there are two possible candidates for NS Mon, probably the star 33822 is the right one (the one with the highest WS value, and not 33810, the one with the smallest distance to the GCVS position).
All in all, apart from obvious reasons and some things which still have to be checked, (e.g. I haven't checked on the negative WS stars), the criterion WS > 1 is very efficient indeed !