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1) Each line has four fields separated by space character(s) [May be variable in number]. The four fields represent the name of the object, the observed date in UT (Universal Time), the magnitude, and the observer's name or code.
2) The name of the object should not be omitted in every lines, otherwise line- oriented tools like grep in UNIX would miss the observations. The variable star name has the 3-letter constellation code in upper case letters, immediately (without placing spaces) followed by its name in the constellation. The examples are: DRAAG for AG Dra, CYGSS for SS Cyg, HERalpha for alpha Her, AQLnova1995 for Nova Aql 1995 etc. Although the conventional names like AG Dra or Nova Aql 1995 are, of course, much more familiar to most observers, they have difficulties in that they have different number of space characters which have always posed a problem in automatic data selection. From experiences in archiving the VSOLJ data, the name in the present rule has been found to work very well (placing the constellation at the beginning also enables simple sorting to get a order which are familiar to variable star observers; simple sorting of the data written in conventional names would result a notoriously unfamiliar order of objects).
Standard expression of Greek letters
3) The observed time should be written in UT (UTC here). This preference is because JD (Julian Date) seems to be less familiar outside variable star specialist group, and because expression in UT would be more easily checked. We recommend observers to write the year in four digits, the month in two digits and the day and its fraction, like 20000720.123 which means 2000 July 20.123 UT. Please write the year and month in each line of observations; otherwise they would become difficult to find in automatic selection. Previous formats using the last two digits of the year (like 000720.123) is still acceptable, but the above Y2K-compilant format is more recommended.
4) The decimal point in magnitudes can be only omitted when the observations are given to a precision of 0.1 mag (as in most frequently reported visual observations). Observers are recommended to always use decimal points to correctly describe the magnitudes. When reporting upper limit observations ("fainter than" estimates), add "<" immediately before the magnitude (avoid placing a space between them). An uncertainty symbol (":") can immediately follow the magnitde (avoid placing a space between them).
Bad examples: 6 for 0.6, 923 for 9.23
Avoid truncating zeros (as in usual scientific expressions) when there can be a loss of siginificant digits. (Avoid writing 9.1 for 9.10, when 9.10 has the proper siginificant digits; some spreadsheet macros automatically does this job, beware). The same is true for UT expressions.
5) Use an apropriate system symbol for non-visual observations. This symbol should immediately follow the magnitude (or immediately follow the uncertainty symbol, if exists). The symbol must be no longer than three letters, and must be only composed of alphabets (upper/lower case sensitive). Use the predefined symbols whenever possible.
Symbols:
U : (Johnson) U-band (either photoelectric or CCD)
B : (Johnson) B-band (either photoelectric or CCD)
V : (Johnson) V-band (either photoelectric or CCD)
Rc : Kron/Cousins R-band (either photoelectric or CCD)
Ic : Kron/Cousins I-band (either photoelectric or CCD)
Rj : Johnson R-band (either photoelectric or CCD)
Ij : Johnson I-band (either photoelectric or CCD)
R : unspecified R-band (either photoelectric or CCD)
I : unspecified I-band (either photoelectric or CCD)
The definition/preference of R and I bands are different from
authos/generations. In order to avoid any confusion, use
suffix "c" or "j" whenever possible. "unspecified" R or I
band observations may be treated as "unspecified systems" by
later researchers.
u : Stoemgren u-band (either photoelectric or CCD)
b : Stoemgren b-band (either photoelectric or CCD)
y : Stoemgren y-band (either photoelectric or CCD)
Other standard infrared bands (J, H, K, Ks, L, M, N etc.) can be
similarly used. Use "p" instead of prime (use zp for z').
p : unspecified photographic
r : unspecified red (mostly photographic) magnitude
(conventional usage)
C : unspecified unfiltered CCD
CR : unfiltered CCD, zero-point adjusted using an Rc-band
or equivalent comparison star(s)
There are some usages of CV system (unfiltered CCD, zero-point adjusted using a V-band or equivalent comparison stars), but this can be only applied to CCDs with a peak sensitivity close to that of the V band. In most commercial CCDs, the system CR will be more adequate. When there is an uncertainty of the system definition, simply leave the system as C.
Don't use CR or CV to represent CCD R-band observation or CCD V-band observation. You don't need to add CCD or C preceding the system symbol.
In reporting CCD observations (especially when the systems are described in C, CR, CV), please specify your system setup (CCD name, filtered or unfiltered). Simple CV magnitude reports can be confused with (unintentional) CCD V-band observations (note CV is a misuse for a CCD V-band observation, but is sometimes confused).
[NOTE: There are some system symbols historically registered in the VSOLJ database (e = T-Max+PO0; f = Tri-X+PO0; m = unfiltered T-Max; s = reserved for step observation; t = unfiltered Tri-X), which had better to be avoided for describing other systems.]
6) Observer's code (three alphabets, case-sensitive). Usually assigned by the observer's organization. When there is no preassigned code, please ask the VSNET administrator to issue a code. The organizaion name may follow the observer's code after a single dot (.), such as Kat.VSOLJ, SXN.AAVSO.
7) Any supplementary description can follow these fields.
The full lines would become like this:
CYGSS 20000102.456 11.0 Xyz /* write the name, year, month in every line */
GEMU 20020103.234 <14.5 Abc /* example of upper limit observation */
GEMU 20021212.123 14.1: Bcd /* example of an uncertainty symbol */
CEPdelta 20021201.12345 4.12V Cde /* V-band observation */
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