Notes on the NSVS catalog FORMAT 1-12 NSVS Number 13-23 ra in degrees 24-27 error in ra 28-38 dec in degrees 39-42 error in dec 43-51 NSVS magnitude 52-58 error of data around mean 59-65 amplitude (includes bad points) 66-72 average of the errors of the individual data points 73-76 number of points (chosen as NSVS ÔgoodÕ points) 77-82 criteria for S-L 83-95 period for S-L 96-104 criteria for AoV 105-117 period for AoV 118-130 chosen period for typed variables 131-133 assigned type 134-146 comments There are two catalogs: Those that have been assigned types [typed.cat; 13814 entries] and those with periods but whose light curves were never looked at [untyped.cat; 70260 entries]. The latter has nothing in columns 131-146. N.B. the NSVS observe some stars more than once. There was no effort to combine Light curves for these objects. Therefore the same star can have duplicate NSVS numbers and slightly different periods. Periods were searched from .01 -365 days for all light curves with 20 points or more. Two distinct methods were used: the string/rope (S-L) length method based on the Lafler-Kinman statistic (Clarke, D. 2002 A&A, 386, 763) and the analysis of variance method (AoV) (Schwarzenberg-Czerney, A. 1989, MNRAS, 241,153). The criteria for the S-L method was chosen as < .20 and for AoV as >20. Since each of these methods find periods in distinctively different ways, light curves that met EITHER criteria were kept. Variables looked at were inspected for each period (if they differed) and adjusted (usually by simple factions and multiples) to display the best light curve. Variables in untyped.cat were never looked at. TYPED The light curves were typed by shape. About half way through the project the 2MASS database was included and if JHK colors were available they were used to help with typing. The types used were: Eclipsing ew Ð W UMa, contact eb - Beta Lyrae, curved outside of eclipse but distinct eclipses ea - Algol, detached with flat outside eclipse rs Ð RS CVn, eb or ea types with evidence for spots Pulsating dc - dwarf cepheid ÐI have used dc to indicate RR Lyrae shaped light curves < 0.2 days ds - delta scuti rr Ð RR Lyrae periods 0.2 > rr >1.5 days. cp - cepheids periods over 1.5 day, lp = long periods such as the semi regular m - mira Others cv Ð cataclysmic variables, sinusoidal with very narrow eclipses. We did a special search for subdwarf B stars which are included in this category el Ð elliptical, low amplitude, sinusoidal variation. These may also be BY Dra-types and the variation is due to spots Ð no eclipses Counts: ew= 3896; ea=1459; eb=2294; rs=103; dc= 56; ds = 196; rr=1644; cp=721; lp= 489; m= 2851; cv=29; el= 73 Comments [columns 134-146] Ð Some types are easily confused especially for light curves with sparse data. Many ew light curves at 1/2 the period look like ds. Without more coverage some lp look like m. Is the outside variation really flat so it is an ea, or is there some curvature so it is an eb? When the choice became particularly hard, the comments lists the alternate choice. That does not mean if an alternate is not listed the type is iron clad. Other notes are: badper, badp = badperiod bp= bad point in the light curves (I gave up marking these after a while) 1/2x, .5x = period could easily be 1/2 that chosen; also 2x =period could be twice that chosen p? = period unsure, sdb= probably a sub dwarf B star algol, alg= algol type, ncb= near contact binary (I an interested in these so I mark them) calgol, CA,coola= cool Algols GS, giant = giant stars G,g,K,k =approximate spectral type from JHK colors (only occasionally marked) *, ** = stars of interest mainly cool binaries Other notes are not of much interest. Mira variables have horrible period determination since the data seldom covers one period. However they are easy to pick out, except when the data gets thin and the period searcher fails entirely. If they had JHK colors, they were checked for very red colors. Some of the time the period searcher catches the alias at one day or a fraction. It shows the large amplitude of a Mira. A few of these were marked, but are listed having a bad period How to choose between an RR Lyrae and W UMa-type? Take a spectrum! But otherwise the criteria was to try to assess the asymmetry. RR has quick rise. If it looked symmetrical then the period was doubled and it was assigned to ew or eb. If the doubling resulted in two unequal minima that was more confirmation of a ew or eb. The RR Lyrae/cepheid shaped curves were divided by period. Less than 0.2 day = dc; between .2 and 1.5 = rr; > 1.5 cepheid. Others classify the Ôdwarf cepheidsÕ as RR Lyrae. SX Phe are in this region also, and of course delta Scuti stars have similar light curves. If it was a sharp rise I favored dc so I have likely missed many delta Scuti stars mixed in with the ew and dc. In general, aliases at 1 day and at simple fractions and at multiples were excluded from any search. This missed some variables, but kept the confusion down. The data also had weaker aliases near 30 days and some of those were excluded. There are a few low amplitude, nearly sinusoidal, variable with periods > 2 days. Many of these are red. I have marked them el for elliptical and perhaps some of the bluer ones are. Some of them may be 1/2 the chosen period and cepheids or long period variables. However, they are just as likely to be BY Dra stars with spots Ðespecially the red ones.